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[PATCH] bcache: set max writeback rate when I/O request is idle

by Coly Li

Commit b1092c9af9ed ("bcache: allow quick writeback when backing idle") allows the writeback rate to be faster if there is no I/O request on a bcache device. It works well if there is only one bcache device attached to the cache set. If there are many bcache devices attached to a cache set, it may introduce performance regression because multiple faster writeback threads of the idle bcache devices will compete the btree level locks with the bcache device who have I/O requests coming. This patch fixes the above issue by only permitting fast writebac when all bcache devices attached on the cache set are idle. And if one of the bcache devices has new I/O request coming, minimized all writeback throughput immediately and let PI controller __update_writeback_rate() to decide the upcoming writeback rate for each bcache device. Also when all bcache devices are idle, limited wrieback rate to a small number is wast of thoughput, especially when backing devices are slower non-rotation devices (e.g. SATA SSD). This patch sets a max writeback rate for each backing device if the whole cache set is idle. A faster writeback rate in idle time means new I/Os may have more available space for dirty data, and people may observe a better write performance then. Please note bcache may change its cache mode in run time, and this patch still works if the cache mode is switched from writeback mode and there is still dirty data on cache. Fixes: Commit b1092c9af9ed ("bcache: allow quick writeback when backing idle") Cc: stable(a)vger.kernel.org #4.16+ Signed-off-by: Coly Li <colyli(a)suse.de> Cc: Michael Lyle <mlyle(a)lyle.org> --- drivers/md/bcache/bcache.h | 9 +--- drivers/md/bcache/request.c | 42 ++++++++++++++- drivers/md/bcache/sysfs.c | 14 +++-- drivers/md/bcache/util.c | 2 +- drivers/md/bcache/util.h | 2 +- drivers/md/bcache/writeback.c | 98 +++++++++++++++++++++++++---------- 6 files changed, 126 insertions(+), 41 deletions(-) diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index d6bf294f3907..f7451e8be03c 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -328,13 +328,6 @@ struct cached_dev { */ atomic_t has_dirty; - /* - * Set to zero by things that touch the backing volume-- except - * writeback. Incremented by writeback. Used to determine when to - * accelerate idle writeback. - */ - atomic_t backing_idle; - struct bch_ratelimit writeback_rate; struct delayed_work writeback_rate_update; @@ -514,6 +507,8 @@ struct cache_set { struct cache_accounting accounting; unsigned long flags; + atomic_t idle_counter; + atomic_t at_max_writeback_rate; struct cache_sb sb; diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c index ae67f5fa8047..fe45f561a054 100644 --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -1104,6 +1104,34 @@ static void detached_dev_do_request(struct bcache_device *d, struct bio *bio) /* Cached devices - read & write stuff */ +static void quit_max_writeback_rate(struct cache_set *c) +{ + int i; + struct bcache_device *d; + struct cached_dev *dc; + + mutex_lock(&bch_register_lock); + + for (i = 0; i < c->devices_max_used; i++) { + if (!c->devices[i]) + continue; + + if (UUID_FLASH_ONLY(&c->uuids[i])) + continue; + + d = c->devices[i]; + dc = container_of(d, struct cached_dev, disk); + /* + * set writeback rate to default minimum value, + * then let update_writeback_rate() to decide the + * upcoming rate. + */ + atomic64_set(&dc->writeback_rate.rate, 1); + } + + mutex_unlock(&bch_register_lock); +} + static blk_qc_t cached_dev_make_request(struct request_queue *q, struct bio *bio) { @@ -1119,7 +1147,19 @@ static blk_qc_t cached_dev_make_request(struct request_queue *q, return BLK_QC_T_NONE; } - atomic_set(&dc->backing_idle, 0); + if (d->c) { + atomic_set(&d->c->idle_counter, 0); + /* + * If at_max_writeback_rate of cache set is true and new I/O + * comes, quit max writeback rate of all cached devices + * attached to this cache set, and set at_max_writeback_rate + * to false. + */ + if (unlikely(atomic_read(&d->c->at_max_writeback_rate) == 1)) { + atomic_set(&d->c->at_max_writeback_rate, 0); + quit_max_writeback_rate(d->c); + } + } generic_start_io_acct(q, rw, bio_sectors(bio), &d->disk->part0); bio_set_dev(bio, dc->bdev); diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index 225b15aa0340..d719021bff81 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -170,7 +170,8 @@ SHOW(__bch_cached_dev) var_printf(writeback_running, "%i"); var_print(writeback_delay); var_print(writeback_percent); - sysfs_hprint(writeback_rate, dc->writeback_rate.rate << 9); + sysfs_hprint(writeback_rate, + atomic64_read(&dc->writeback_rate.rate) << 9); sysfs_hprint(io_errors, atomic_read(&dc->io_errors)); sysfs_printf(io_error_limit, "%i", dc->error_limit); sysfs_printf(io_disable, "%i", dc->io_disable); @@ -188,7 +189,8 @@ SHOW(__bch_cached_dev) char change[20]; s64 next_io; - bch_hprint(rate, dc->writeback_rate.rate << 9); + bch_hprint(rate, + atomic64_read(&dc->writeback_rate.rate) << 9); bch_hprint(dirty, bcache_dev_sectors_dirty(&dc->disk) << 9); bch_hprint(target, dc->writeback_rate_target << 9); bch_hprint(proportional,dc->writeback_rate_proportional << 9); @@ -255,8 +257,12 @@ STORE(__cached_dev) sysfs_strtoul_clamp(writeback_percent, dc->writeback_percent, 0, 40); - sysfs_strtoul_clamp(writeback_rate, - dc->writeback_rate.rate, 1, INT_MAX); + if (attr == &sysfs_writeback_rate) { + int v; + + sysfs_strtoul_clamp(writeback_rate, v, 1, INT_MAX); + atomic64_set(&dc->writeback_rate.rate, v); + } sysfs_strtoul_clamp(writeback_rate_update_seconds, dc->writeback_rate_update_seconds, diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c index fc479b026d6d..84f90c3d996d 100644 --- a/drivers/md/bcache/util.c +++ b/drivers/md/bcache/util.c @@ -200,7 +200,7 @@ uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done) { uint64_t now = local_clock(); - d->next += div_u64(done * NSEC_PER_SEC, d->rate); + d->next += div_u64(done * NSEC_PER_SEC, atomic64_read(&d->rate)); /* Bound the time. Don't let us fall further than 2 seconds behind * (this prevents unnecessary backlog that would make it impossible diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h index cced87f8eb27..7e17f32ab563 100644 --- a/drivers/md/bcache/util.h +++ b/drivers/md/bcache/util.h @@ -442,7 +442,7 @@ struct bch_ratelimit { * Rate at which we want to do work, in units per second * The units here correspond to the units passed to bch_next_delay() */ - uint32_t rate; + atomic64_t rate; }; static inline void bch_ratelimit_reset(struct bch_ratelimit *d) diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c index ad45ebe1a74b..72059f910230 100644 --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -49,6 +49,63 @@ static uint64_t __calc_target_rate(struct cached_dev *dc) return (cache_dirty_target * bdev_share) >> WRITEBACK_SHARE_SHIFT; } +static bool set_at_max_writeback_rate(struct cache_set *c, + struct cached_dev *dc) +{ + int i, dirty_dc_nr = 0; + struct bcache_device *d; + + mutex_lock(&bch_register_lock); + for (i = 0; i < c->devices_max_used; i++) { + if (!c->devices[i]) + continue; + if (UUID_FLASH_ONLY(&c->uuids[i])) + continue; + d = c->devices[i]; + dc = container_of(d, struct cached_dev, disk); + if (atomic_read(&dc->has_dirty)) + dirty_dc_nr++; + } + mutex_unlock(&bch_register_lock); + + /* + * Idle_counter is increased everytime when update_writeback_rate() + * is rescheduled in. If all backing devices attached to the same + * cache set has same dc->writeback_rate_update_seconds value, it + * is about 10 rounds of update_writeback_rate() is called on each + * backing device, then the code will fall through at set 1 to + * c->at_max_writeback_rate, and a max wrteback rate to each + * dc->writeback_rate.rate. This is not very accurate but works well + * to make sure the whole cache set has no new I/O coming before + * writeback rate is set to a max number. + */ + if (atomic_inc_return(&c->idle_counter) < dirty_dc_nr * 10) + return false; + + if (atomic_read(&c->at_max_writeback_rate) != 1) + atomic_set(&c->at_max_writeback_rate, 1); + + + atomic64_set(&dc->writeback_rate.rate, INT_MAX); + + /* keep writeback_rate_target as existing value */ + dc->writeback_rate_proportional = 0; + dc->writeback_rate_integral_scaled = 0; + dc->writeback_rate_change = 0; + + /* + * Check c->idle_counter and c->at_max_writeback_rate agagain in case + * new I/O arrives during before set_at_max_writeback_rate() returns. + * Then the writeback rate is set to 1, and its new value should be + * decided via __update_writeback_rate(). + */ + if (atomic_read(&c->idle_counter) < dirty_dc_nr * 10 || + !atomic_read(&c->at_max_writeback_rate)) + return false; + + return true; +} + static void __update_writeback_rate(struct cached_dev *dc) { /* @@ -104,8 +161,9 @@ static void __update_writeback_rate(struct cached_dev *dc) dc->writeback_rate_proportional = proportional_scaled; dc->writeback_rate_integral_scaled = integral_scaled; - dc->writeback_rate_change = new_rate - dc->writeback_rate.rate; - dc->writeback_rate.rate = new_rate; + dc->writeback_rate_change = new_rate - + atomic64_read(&dc->writeback_rate.rate); + atomic64_set(&dc->writeback_rate.rate, new_rate); dc->writeback_rate_target = target; } @@ -138,9 +196,16 @@ static void update_writeback_rate(struct work_struct *work) down_read(&dc->writeback_lock); - if (atomic_read(&dc->has_dirty) && - dc->writeback_percent) - __update_writeback_rate(dc); + if (atomic_read(&dc->has_dirty) && dc->writeback_percent) { + /* + * If the whole cache set is idle, set_at_max_writeback_rate() + * will set writeback rate to a max number. Then it is + * unncessary to update writeback rate for an idle cache set + * in maximum writeback rate number(s). + */ + if (!set_at_max_writeback_rate(c, dc)) + __update_writeback_rate(dc); + } up_read(&dc->writeback_lock); @@ -422,27 +487,6 @@ static void read_dirty(struct cached_dev *dc) delay = writeback_delay(dc, size); - /* If the control system would wait for at least half a - * second, and there's been no reqs hitting the backing disk - * for awhile: use an alternate mode where we have at most - * one contiguous set of writebacks in flight at a time. If - * someone wants to do IO it will be quick, as it will only - * have to contend with one operation in flight, and we'll - * be round-tripping data to the backing disk as quickly as - * it can accept it. - */ - if (delay >= HZ / 2) { - /* 3 means at least 1.5 seconds, up to 7.5 if we - * have slowed way down. - */ - if (atomic_inc_return(&dc->backing_idle) >= 3) { - /* Wait for current I/Os to finish */ - closure_sync(&cl); - /* And immediately launch a new set. */ - delay = 0; - } - } - while (!kthread_should_stop() && !test_bit(CACHE_SET_IO_DISABLE, &dc->disk.c->flags) && delay) { @@ -715,7 +759,7 @@ void bch_cached_dev_writeback_init(struct cached_dev *dc) dc->writeback_running = true; dc->writeback_percent = 10; dc->writeback_delay = 30; - dc->writeback_rate.rate = 1024; + atomic64_set(&dc->writeback_rate.rate, 1024); dc->writeback_rate_minimum = 8; dc->writeback_rate_update_seconds = WRITEBACK_RATE_UPDATE_SECS_DEFAULT; -- 2.17.1

7 years, 5 months

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[PATCH 12/12] can: xilinx_can: fix power management handling

by Marc Kleine-Budde

From: Anssi Hannula <anssi.hannula(a)bitwise.fi> There are several issues with the suspend/resume handling code of the driver: - The device is attached and detached in the runtime_suspend() and runtime_resume() callbacks if the interface is running. However, during xcan_chip_start() the interface is considered running, causing the resume handler to incorrectly call netif_start_queue() at the beginning of xcan_chip_start(), and on xcan_chip_start() error return the suspend handler detaches the device leaving the user unable to bring-up the device anymore. - The device is not brought properly up on system resume. A reset is done and the code tries to determine the bus state after that. However, after reset the device is always in Configuration mode (down), so the state checking code does not make sense and communication will also not work. - The suspend callback tries to set the device to sleep mode (low-power mode which monitors the bus and brings the device back to normal mode on activity), but then immediately disables the clocks (possibly before the device reaches the sleep mode), which does not make sense to me. If a clean shutdown is wanted before disabling clocks, we can just bring it down completely instead of only sleep mode. Reorganize the PM code so that only the clock logic remains in the runtime PM callbacks and the system PM callbacks contain the device bring-up/down logic. This makes calling the runtime PM callbacks during e.g. xcan_chip_start() safe. The system PM callbacks now simply call common code to start/stop the HW if the interface was running, replacing the broken code from before. xcan_chip_stop() is updated to use the common reset code so that it will wait for the reset to complete. Reset also disables all interrupts so do not do that separately. Also, the device_may_wakeup() checks are removed as the driver does not have wakeup support. Tested on Zynq-7000 integrated CAN. Signed-off-by: Anssi Hannula <anssi.hannula(a)bitwise.fi> Cc: Michal Simek <michal.simek(a)xilinx.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl(a)pengutronix.de> --- drivers/net/can/xilinx_can.c | 69 +++++++++++++++--------------------- 1 file changed, 28 insertions(+), 41 deletions(-) diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index cb80a9aa7281..5a24039733ef 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -984,13 +984,9 @@ static irqreturn_t xcan_interrupt(int irq, void *dev_id) static void xcan_chip_stop(struct net_device *ndev) { struct xcan_priv *priv = netdev_priv(ndev); - u32 ier; /* Disable interrupts and leave the can in configuration mode */ - ier = priv->read_reg(priv, XCAN_IER_OFFSET); - ier &= ~XCAN_INTR_ALL; - priv->write_reg(priv, XCAN_IER_OFFSET, ier); - priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK); + set_reset_mode(ndev); priv->can.state = CAN_STATE_STOPPED; } @@ -1123,10 +1119,15 @@ static const struct net_device_ops xcan_netdev_ops = { */ static int __maybe_unused xcan_suspend(struct device *dev) { - if (!device_may_wakeup(dev)) - return pm_runtime_force_suspend(dev); + struct net_device *ndev = dev_get_drvdata(dev); - return 0; + if (netif_running(ndev)) { + netif_stop_queue(ndev); + netif_device_detach(ndev); + xcan_chip_stop(ndev); + } + + return pm_runtime_force_suspend(dev); } /** @@ -1138,11 +1139,27 @@ static int __maybe_unused xcan_suspend(struct device *dev) */ static int __maybe_unused xcan_resume(struct device *dev) { - if (!device_may_wakeup(dev)) - return pm_runtime_force_resume(dev); + struct net_device *ndev = dev_get_drvdata(dev); + int ret; - return 0; + ret = pm_runtime_force_resume(dev); + if (ret) { + dev_err(dev, "pm_runtime_force_resume failed on resume\n"); + return ret; + } + + if (netif_running(ndev)) { + ret = xcan_chip_start(ndev); + if (ret) { + dev_err(dev, "xcan_chip_start failed on resume\n"); + return ret; + } + netif_device_attach(ndev); + netif_start_queue(ndev); + } + + return 0; } /** @@ -1157,14 +1174,6 @@ static int __maybe_unused xcan_runtime_suspend(struct device *dev) struct net_device *ndev = dev_get_drvdata(dev); struct xcan_priv *priv = netdev_priv(ndev); - if (netif_running(ndev)) { - netif_stop_queue(ndev); - netif_device_detach(ndev); - } - - priv->write_reg(priv, XCAN_MSR_OFFSET, XCAN_MSR_SLEEP_MASK); - priv->can.state = CAN_STATE_SLEEPING; - clk_disable_unprepare(priv->bus_clk); clk_disable_unprepare(priv->can_clk); @@ -1183,7 +1192,6 @@ static int __maybe_unused xcan_runtime_resume(struct device *dev) struct net_device *ndev = dev_get_drvdata(dev); struct xcan_priv *priv = netdev_priv(ndev); int ret; - u32 isr, status; ret = clk_prepare_enable(priv->bus_clk); if (ret) { @@ -1197,27 +1205,6 @@ static int __maybe_unused xcan_runtime_resume(struct device *dev) return ret; } - priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK); - isr = priv->read_reg(priv, XCAN_ISR_OFFSET); - status = priv->read_reg(priv, XCAN_SR_OFFSET); - - if (netif_running(ndev)) { - if (isr & XCAN_IXR_BSOFF_MASK) { - priv->can.state = CAN_STATE_BUS_OFF; - priv->write_reg(priv, XCAN_SRR_OFFSET, - XCAN_SRR_RESET_MASK); - } else if ((status & XCAN_SR_ESTAT_MASK) == - XCAN_SR_ESTAT_MASK) { - priv->can.state = CAN_STATE_ERROR_PASSIVE; - } else if (status & XCAN_SR_ERRWRN_MASK) { - priv->can.state = CAN_STATE_ERROR_WARNING; - } else { - priv->can.state = CAN_STATE_ERROR_ACTIVE; - } - netif_device_attach(ndev); - netif_start_queue(ndev); - } - return 0; } -- 2.18.0

7 years, 5 months

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[PATCH 11/12] can: xilinx_can: fix incorrect clear of non-processed interrupts

by Marc Kleine-Budde

From: Anssi Hannula <anssi.hannula(a)bitwise.fi> xcan_interrupt() clears ERROR|RXOFLV|BSOFF|ARBLST interrupts if any of them is asserted. This does not take into account that some of them could have been asserted between interrupt status read and interrupt clear, therefore clearing them without handling them. Fix the code to only clear those interrupts that it knows are asserted and therefore going to be processed in xcan_err_interrupt(). Fixes: b1201e44f50b ("can: xilinx CAN controller support") Signed-off-by: Anssi Hannula <anssi.hannula(a)bitwise.fi> Cc: Michal Simek <michal.simek(a)xilinx.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl(a)pengutronix.de> --- drivers/net/can/xilinx_can.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index ea9f9d1a5ba7..cb80a9aa7281 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -938,6 +938,7 @@ static irqreturn_t xcan_interrupt(int irq, void *dev_id) struct net_device *ndev = (struct net_device *)dev_id; struct xcan_priv *priv = netdev_priv(ndev); u32 isr, ier; + u32 isr_errors; /* Get the interrupt status from Xilinx CAN */ isr = priv->read_reg(priv, XCAN_ISR_OFFSET); @@ -956,11 +957,10 @@ static irqreturn_t xcan_interrupt(int irq, void *dev_id) xcan_tx_interrupt(ndev, isr); /* Check for the type of error interrupt and Processing it */ - if (isr & (XCAN_IXR_ERROR_MASK | XCAN_IXR_RXOFLW_MASK | - XCAN_IXR_BSOFF_MASK | XCAN_IXR_ARBLST_MASK)) { - priv->write_reg(priv, XCAN_ICR_OFFSET, (XCAN_IXR_ERROR_MASK | - XCAN_IXR_RXOFLW_MASK | XCAN_IXR_BSOFF_MASK | - XCAN_IXR_ARBLST_MASK)); + isr_errors = isr & (XCAN_IXR_ERROR_MASK | XCAN_IXR_RXOFLW_MASK | + XCAN_IXR_BSOFF_MASK | XCAN_IXR_ARBLST_MASK); + if (isr_errors) { + priv->write_reg(priv, XCAN_ICR_OFFSET, isr_errors); xcan_err_interrupt(ndev, isr); } -- 2.18.0

7 years, 5 months

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[PATCH 10/12] can: xilinx_can: fix RX overflow interrupt not being enabled

by Marc Kleine-Budde

From: Anssi Hannula <anssi.hannula(a)bitwise.fi> RX overflow interrupt (RXOFLW) is disabled even though xcan_interrupt() processes it. This means that an RX overflow interrupt will only be processed when another interrupt gets asserted (e.g. for RX/TX). Fix that by enabling the RXOFLW interrupt. Fixes: b1201e44f50b ("can: xilinx CAN controller support") Signed-off-by: Anssi Hannula <anssi.hannula(a)bitwise.fi> Cc: Michal Simek <michal.simek(a)xilinx.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl(a)pengutronix.de> --- drivers/net/can/xilinx_can.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index dcbdc3cd651c..ea9f9d1a5ba7 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -104,7 +104,7 @@ enum xcan_reg { #define XCAN_INTR_ALL (XCAN_IXR_TXOK_MASK | XCAN_IXR_BSOFF_MASK |\ XCAN_IXR_WKUP_MASK | XCAN_IXR_SLP_MASK | \ XCAN_IXR_RXNEMP_MASK | XCAN_IXR_ERROR_MASK | \ - XCAN_IXR_ARBLST_MASK) + XCAN_IXR_RXOFLW_MASK | XCAN_IXR_ARBLST_MASK) /* CAN register bit shift - XCAN_<REG>_<BIT>_SHIFT */ #define XCAN_BTR_SJW_SHIFT 7 /* Synchronous jump width */ -- 2.18.0

7 years, 5 months

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[PATCH 09/12] can: xilinx_can: keep only 1-2 frames in TX FIFO to fix TX accounting

by Marc Kleine-Budde

From: Anssi Hannula <anssi.hannula(a)bitwise.fi> The xilinx_can driver assumes that the TXOK interrupt only clears after it has been acknowledged as many times as there have been successfully sent frames. However, the documentation does not mention such behavior, instead saying just that the interrupt is cleared when the clear bit is set. Similarly, testing seems to also suggest that it is immediately cleared regardless of the amount of frames having been sent. Performing some heavy TX load and then going back to idle has the tx_head drifting further away from tx_tail over time, steadily reducing the amount of frames the driver keeps in the TX FIFO (but not to zero, as the TXOK interrupt always frees up space for 1 frame from the driver's perspective, so frames continue to be sent) and delaying the local echo frames. The TX FIFO tracking is also otherwise buggy as it does not account for TX FIFO being cleared after software resets, causing BUG!, TX FIFO full when queue awake! messages to be output. There does not seem to be any way to accurately track the state of the TX FIFO for local echo support while using the full TX FIFO. The Zynq version of the HW (but not the soft-AXI version) has watermark programming support and with it an additional TX-FIFO-empty interrupt bit. Modify the driver to only put 1 frame into TX FIFO at a time on soft-AXI and 2 frames at a time on Zynq. On Zynq the TXFEMP interrupt bit is used to detect whether 1 or 2 frames have been sent at interrupt processing time. Tested with the integrated CAN on Zynq-7000 SoC. The 1-frame-FIFO mode was also tested. An alternative way to solve this would be to drop local echo support but keep using the full TX FIFO. v2: Add FIFO space check before TX queue wake with locking to synchronize with queue stop. This avoids waking the queue when xmit() had just filled it. v3: Keep local echo support and reduce the amount of frames in FIFO instead as suggested by Marc Kleine-Budde. Fixes: b1201e44f50b ("can: xilinx CAN controller support") Signed-off-by: Anssi Hannula <anssi.hannula(a)bitwise.fi> Cc: <stable(a)vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl(a)pengutronix.de> --- drivers/net/can/xilinx_can.c | 139 +++++++++++++++++++++++++++++++---- 1 file changed, 123 insertions(+), 16 deletions(-) diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index 763408a3eafb..dcbdc3cd651c 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -26,8 +26,10 @@ #include <linux/module.h> #include <linux/netdevice.h> #include <linux/of.h> +#include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/skbuff.h> +#include <linux/spinlock.h> #include <linux/string.h> #include <linux/types.h> #include <linux/can/dev.h> @@ -119,6 +121,7 @@ enum xcan_reg { /** * struct xcan_priv - This definition define CAN driver instance * @can: CAN private data structure. + * @tx_lock: Lock for synchronizing TX interrupt handling * @tx_head: Tx CAN packets ready to send on the queue * @tx_tail: Tx CAN packets successfully sended on the queue * @tx_max: Maximum number packets the driver can send @@ -133,6 +136,7 @@ enum xcan_reg { */ struct xcan_priv { struct can_priv can; + spinlock_t tx_lock; unsigned int tx_head; unsigned int tx_tail; unsigned int tx_max; @@ -160,6 +164,11 @@ static const struct can_bittiming_const xcan_bittiming_const = { .brp_inc = 1, }; +#define XCAN_CAP_WATERMARK 0x0001 +struct xcan_devtype_data { + unsigned int caps; +}; + /** * xcan_write_reg_le - Write a value to the device register little endian * @priv: Driver private data structure @@ -239,6 +248,10 @@ static int set_reset_mode(struct net_device *ndev) usleep_range(500, 10000); } + /* reset clears FIFOs */ + priv->tx_head = 0; + priv->tx_tail = 0; + return 0; } @@ -393,6 +406,7 @@ static int xcan_start_xmit(struct sk_buff *skb, struct net_device *ndev) struct net_device_stats *stats = &ndev->stats; struct can_frame *cf = (struct can_frame *)skb->data; u32 id, dlc, data[2] = {0, 0}; + unsigned long flags; if (can_dropped_invalid_skb(ndev, skb)) return NETDEV_TX_OK; @@ -440,6 +454,9 @@ static int xcan_start_xmit(struct sk_buff *skb, struct net_device *ndev) data[1] = be32_to_cpup((__be32 *)(cf->data + 4)); can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max); + + spin_lock_irqsave(&priv->tx_lock, flags); + priv->tx_head++; /* Write the Frame to Xilinx CAN TX FIFO */ @@ -455,10 +472,16 @@ static int xcan_start_xmit(struct sk_buff *skb, struct net_device *ndev) stats->tx_bytes += cf->can_dlc; } + /* Clear TX-FIFO-empty interrupt for xcan_tx_interrupt() */ + if (priv->tx_max > 1) + priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXFEMP_MASK); + /* Check if the TX buffer is full */ if ((priv->tx_head - priv->tx_tail) == priv->tx_max) netif_stop_queue(ndev); + spin_unlock_irqrestore(&priv->tx_lock, flags); + return NETDEV_TX_OK; } @@ -832,19 +855,71 @@ static void xcan_tx_interrupt(struct net_device *ndev, u32 isr) { struct xcan_priv *priv = netdev_priv(ndev); struct net_device_stats *stats = &ndev->stats; + unsigned int frames_in_fifo; + int frames_sent = 1; /* TXOK => at least 1 frame was sent */ + unsigned long flags; + int retries = 0; + + /* Synchronize with xmit as we need to know the exact number + * of frames in the FIFO to stay in sync due to the TXFEMP + * handling. + * This also prevents a race between netif_wake_queue() and + * netif_stop_queue(). + */ + spin_lock_irqsave(&priv->tx_lock, flags); + + frames_in_fifo = priv->tx_head - priv->tx_tail; - while ((priv->tx_head - priv->tx_tail > 0) && - (isr & XCAN_IXR_TXOK_MASK)) { + if (WARN_ON_ONCE(frames_in_fifo == 0)) { + /* clear TXOK anyway to avoid getting back here */ priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXOK_MASK); + spin_unlock_irqrestore(&priv->tx_lock, flags); + return; + } + + /* Check if 2 frames were sent (TXOK only means that at least 1 + * frame was sent). + */ + if (frames_in_fifo > 1) { + WARN_ON(frames_in_fifo > priv->tx_max); + + /* Synchronize TXOK and isr so that after the loop: + * (1) isr variable is up-to-date at least up to TXOK clear + * time. This avoids us clearing a TXOK of a second frame + * but not noticing that the FIFO is now empty and thus + * marking only a single frame as sent. + * (2) No TXOK is left. Having one could mean leaving a + * stray TXOK as we might process the associated frame + * via TXFEMP handling as we read TXFEMP *after* TXOK + * clear to satisfy (1). + */ + while ((isr & XCAN_IXR_TXOK_MASK) && !WARN_ON(++retries == 100)) { + priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXOK_MASK); + isr = priv->read_reg(priv, XCAN_ISR_OFFSET); + } + + if (isr & XCAN_IXR_TXFEMP_MASK) { + /* nothing in FIFO anymore */ + frames_sent = frames_in_fifo; + } + } else { + /* single frame in fifo, just clear TXOK */ + priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_TXOK_MASK); + } + + while (frames_sent--) { can_get_echo_skb(ndev, priv->tx_tail % priv->tx_max); priv->tx_tail++; stats->tx_packets++; - isr = priv->read_reg(priv, XCAN_ISR_OFFSET); } + + netif_wake_queue(ndev); + + spin_unlock_irqrestore(&priv->tx_lock, flags); + can_led_event(ndev, CAN_LED_EVENT_TX); xcan_update_error_state_after_rxtx(ndev); - netif_wake_queue(ndev); } /** @@ -1151,6 +1226,18 @@ static const struct dev_pm_ops xcan_dev_pm_ops = { SET_RUNTIME_PM_OPS(xcan_runtime_suspend, xcan_runtime_resume, NULL) }; +static const struct xcan_devtype_data xcan_zynq_data = { + .caps = XCAN_CAP_WATERMARK, +}; + +/* Match table for OF platform binding */ +static const struct of_device_id xcan_of_match[] = { + { .compatible = "xlnx,zynq-can-1.0", .data = &xcan_zynq_data }, + { .compatible = "xlnx,axi-can-1.00.a", }, + { /* end of list */ }, +}; +MODULE_DEVICE_TABLE(of, xcan_of_match); + /** * xcan_probe - Platform registration call * @pdev: Handle to the platform device structure @@ -1165,8 +1252,10 @@ static int xcan_probe(struct platform_device *pdev) struct resource *res; /* IO mem resources */ struct net_device *ndev; struct xcan_priv *priv; + const struct of_device_id *of_id; + int caps = 0; void __iomem *addr; - int ret, rx_max, tx_max; + int ret, rx_max, tx_max, tx_fifo_depth; /* Get the virtual base address for the device */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); @@ -1176,7 +1265,8 @@ static int xcan_probe(struct platform_device *pdev) goto err; } - ret = of_property_read_u32(pdev->dev.of_node, "tx-fifo-depth", &tx_max); + ret = of_property_read_u32(pdev->dev.of_node, "tx-fifo-depth", + &tx_fifo_depth); if (ret < 0) goto err; @@ -1184,6 +1274,30 @@ static int xcan_probe(struct platform_device *pdev) if (ret < 0) goto err; + of_id = of_match_device(xcan_of_match, &pdev->dev); + if (of_id) { + const struct xcan_devtype_data *devtype_data = of_id->data; + + if (devtype_data) + caps = devtype_data->caps; + } + + /* There is no way to directly figure out how many frames have been + * sent when the TXOK interrupt is processed. If watermark programming + * is supported, we can have 2 frames in the FIFO and use TXFEMP + * to determine if 1 or 2 frames have been sent. + * Theoretically we should be able to use TXFWMEMP to determine up + * to 3 frames, but it seems that after putting a second frame in the + * FIFO, with watermark at 2 frames, it can happen that TXFWMEMP (less + * than 2 frames in FIFO) is set anyway with no TXOK (a frame was + * sent), which is not a sensible state - possibly TXFWMEMP is not + * completely synchronized with the rest of the bits? + */ + if (caps & XCAN_CAP_WATERMARK) + tx_max = min(tx_fifo_depth, 2); + else + tx_max = 1; + /* Create a CAN device instance */ ndev = alloc_candev(sizeof(struct xcan_priv), tx_max); if (!ndev) @@ -1198,6 +1312,7 @@ static int xcan_probe(struct platform_device *pdev) CAN_CTRLMODE_BERR_REPORTING; priv->reg_base = addr; priv->tx_max = tx_max; + spin_lock_init(&priv->tx_lock); /* Get IRQ for the device */ ndev->irq = platform_get_irq(pdev, 0); @@ -1262,9 +1377,9 @@ static int xcan_probe(struct platform_device *pdev) pm_runtime_put(&pdev->dev); - netdev_dbg(ndev, "reg_base=0x%p irq=%d clock=%d, tx fifo depth:%d\n", + netdev_dbg(ndev, "reg_base=0x%p irq=%d clock=%d, tx fifo depth: actual %d, using %d\n", priv->reg_base, ndev->irq, priv->can.clock.freq, - priv->tx_max); + tx_fifo_depth, priv->tx_max); return 0; @@ -1298,14 +1413,6 @@ static int xcan_remove(struct platform_device *pdev) return 0; } -/* Match table for OF platform binding */ -static const struct of_device_id xcan_of_match[] = { - { .compatible = "xlnx,zynq-can-1.0", }, - { .compatible = "xlnx,axi-can-1.00.a", }, - { /* end of list */ }, -}; -MODULE_DEVICE_TABLE(of, xcan_of_match); - static struct platform_driver xcan_driver = { .probe = xcan_probe, .remove = xcan_remove, -- 2.18.0

7 years, 5 months

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[PATCH 08/12] can: xilinx_can: fix recovery from error states not being propagated

by Marc Kleine-Budde

From: Anssi Hannula <anssi.hannula(a)bitwise.fi> The xilinx_can driver contains no mechanism for propagating recovery from CAN_STATE_ERROR_WARNING and CAN_STATE_ERROR_PASSIVE. Add such a mechanism by factoring the handling of XCAN_STATE_ERROR_PASSIVE and XCAN_STATE_ERROR_WARNING out of xcan_err_interrupt and checking for recovery after RX and TX if the interface is in one of those states. Tested with the integrated CAN on Zynq-7000 SoC. Fixes: b1201e44f50b ("can: xilinx CAN controller support") Signed-off-by: Anssi Hannula <anssi.hannula(a)bitwise.fi> Cc: <stable(a)vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl(a)pengutronix.de> --- drivers/net/can/xilinx_can.c | 155 ++++++++++++++++++++++++++++------- 1 file changed, 127 insertions(+), 28 deletions(-) diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index 1bda47aa62f5..763408a3eafb 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -2,6 +2,7 @@ * * Copyright (C) 2012 - 2014 Xilinx, Inc. * Copyright (C) 2009 PetaLogix. All rights reserved. + * Copyright (C) 2017 Sandvik Mining and Construction Oy * * Description: * This driver is developed for Axi CAN IP and for Zynq CANPS Controller. @@ -529,6 +530,123 @@ static int xcan_rx(struct net_device *ndev) return 1; } +/** + * xcan_current_error_state - Get current error state from HW + * @ndev: Pointer to net_device structure + * + * Checks the current CAN error state from the HW. Note that this + * only checks for ERROR_PASSIVE and ERROR_WARNING. + * + * Return: + * ERROR_PASSIVE or ERROR_WARNING if either is active, ERROR_ACTIVE + * otherwise. + */ +static enum can_state xcan_current_error_state(struct net_device *ndev) +{ + struct xcan_priv *priv = netdev_priv(ndev); + u32 status = priv->read_reg(priv, XCAN_SR_OFFSET); + + if ((status & XCAN_SR_ESTAT_MASK) == XCAN_SR_ESTAT_MASK) + return CAN_STATE_ERROR_PASSIVE; + else if (status & XCAN_SR_ERRWRN_MASK) + return CAN_STATE_ERROR_WARNING; + else + return CAN_STATE_ERROR_ACTIVE; +} + +/** + * xcan_set_error_state - Set new CAN error state + * @ndev: Pointer to net_device structure + * @new_state: The new CAN state to be set + * @cf: Error frame to be populated or NULL + * + * Set new CAN error state for the device, updating statistics and + * populating the error frame if given. + */ +static void xcan_set_error_state(struct net_device *ndev, + enum can_state new_state, + struct can_frame *cf) +{ + struct xcan_priv *priv = netdev_priv(ndev); + u32 ecr = priv->read_reg(priv, XCAN_ECR_OFFSET); + u32 txerr = ecr & XCAN_ECR_TEC_MASK; + u32 rxerr = (ecr & XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT; + + priv->can.state = new_state; + + if (cf) { + cf->can_id |= CAN_ERR_CRTL; + cf->data[6] = txerr; + cf->data[7] = rxerr; + } + + switch (new_state) { + case CAN_STATE_ERROR_PASSIVE: + priv->can.can_stats.error_passive++; + if (cf) + cf->data[1] = (rxerr > 127) ? + CAN_ERR_CRTL_RX_PASSIVE : + CAN_ERR_CRTL_TX_PASSIVE; + break; + case CAN_STATE_ERROR_WARNING: + priv->can.can_stats.error_warning++; + if (cf) + cf->data[1] |= (txerr > rxerr) ? + CAN_ERR_CRTL_TX_WARNING : + CAN_ERR_CRTL_RX_WARNING; + break; + case CAN_STATE_ERROR_ACTIVE: + if (cf) + cf->data[1] |= CAN_ERR_CRTL_ACTIVE; + break; + default: + /* non-ERROR states are handled elsewhere */ + WARN_ON(1); + break; + } +} + +/** + * xcan_update_error_state_after_rxtx - Update CAN error state after RX/TX + * @ndev: Pointer to net_device structure + * + * If the device is in a ERROR-WARNING or ERROR-PASSIVE state, check if + * the performed RX/TX has caused it to drop to a lesser state and set + * the interface state accordingly. + */ +static void xcan_update_error_state_after_rxtx(struct net_device *ndev) +{ + struct xcan_priv *priv = netdev_priv(ndev); + enum can_state old_state = priv->can.state; + enum can_state new_state; + + /* changing error state due to successful frame RX/TX can only + * occur from these states + */ + if (old_state != CAN_STATE_ERROR_WARNING && + old_state != CAN_STATE_ERROR_PASSIVE) + return; + + new_state = xcan_current_error_state(ndev); + + if (new_state != old_state) { + struct sk_buff *skb; + struct can_frame *cf; + + skb = alloc_can_err_skb(ndev, &cf); + + xcan_set_error_state(ndev, new_state, skb ? cf : NULL); + + if (skb) { + struct net_device_stats *stats = &ndev->stats; + + stats->rx_packets++; + stats->rx_bytes += cf->can_dlc; + netif_rx(skb); + } + } +} + /** * xcan_err_interrupt - error frame Isr * @ndev: net_device pointer @@ -544,16 +662,12 @@ static void xcan_err_interrupt(struct net_device *ndev, u32 isr) struct net_device_stats *stats = &ndev->stats; struct can_frame *cf; struct sk_buff *skb; - u32 err_status, status, txerr = 0, rxerr = 0; + u32 err_status; skb = alloc_can_err_skb(ndev, &cf); err_status = priv->read_reg(priv, XCAN_ESR_OFFSET); priv->write_reg(priv, XCAN_ESR_OFFSET, err_status); - txerr = priv->read_reg(priv, XCAN_ECR_OFFSET) & XCAN_ECR_TEC_MASK; - rxerr = ((priv->read_reg(priv, XCAN_ECR_OFFSET) & - XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT); - status = priv->read_reg(priv, XCAN_SR_OFFSET); if (isr & XCAN_IXR_BSOFF_MASK) { priv->can.state = CAN_STATE_BUS_OFF; @@ -563,28 +677,10 @@ static void xcan_err_interrupt(struct net_device *ndev, u32 isr) can_bus_off(ndev); if (skb) cf->can_id |= CAN_ERR_BUSOFF; - } else if ((status & XCAN_SR_ESTAT_MASK) == XCAN_SR_ESTAT_MASK) { - priv->can.state = CAN_STATE_ERROR_PASSIVE; - priv->can.can_stats.error_passive++; - if (skb) { - cf->can_id |= CAN_ERR_CRTL; - cf->data[1] = (rxerr > 127) ? - CAN_ERR_CRTL_RX_PASSIVE : - CAN_ERR_CRTL_TX_PASSIVE; - cf->data[6] = txerr; - cf->data[7] = rxerr; - } - } else if (status & XCAN_SR_ERRWRN_MASK) { - priv->can.state = CAN_STATE_ERROR_WARNING; - priv->can.can_stats.error_warning++; - if (skb) { - cf->can_id |= CAN_ERR_CRTL; - cf->data[1] |= (txerr > rxerr) ? - CAN_ERR_CRTL_TX_WARNING : - CAN_ERR_CRTL_RX_WARNING; - cf->data[6] = txerr; - cf->data[7] = rxerr; - } + } else { + enum can_state new_state = xcan_current_error_state(ndev); + + xcan_set_error_state(ndev, new_state, skb ? cf : NULL); } /* Check for Arbitration lost interrupt */ @@ -713,8 +809,10 @@ static int xcan_rx_poll(struct napi_struct *napi, int quota) isr = priv->read_reg(priv, XCAN_ISR_OFFSET); } - if (work_done) + if (work_done) { can_led_event(ndev, CAN_LED_EVENT_RX); + xcan_update_error_state_after_rxtx(ndev); + } if (work_done < quota) { napi_complete_done(napi, work_done); @@ -745,6 +843,7 @@ static void xcan_tx_interrupt(struct net_device *ndev, u32 isr) isr = priv->read_reg(priv, XCAN_ISR_OFFSET); } can_led_event(ndev, CAN_LED_EVENT_TX); + xcan_update_error_state_after_rxtx(ndev); netif_wake_queue(ndev); } -- 2.18.0

7 years, 5 months

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[PATCH 07/12] can: xilinx_can: fix RX loop if RXNEMP is asserted without RXOK

by Marc Kleine-Budde

From: Anssi Hannula <anssi.hannula(a)bitwise.fi> If the device gets into a state where RXNEMP (RX FIFO not empty) interrupt is asserted without RXOK (new frame received successfully) interrupt being asserted, xcan_rx_poll() will continue to try to clear RXNEMP without actually reading frames from RX FIFO. If the RX FIFO is not empty, the interrupt will not be cleared and napi_schedule() will just be called again. This situation can occur when: (a) xcan_rx() returns without reading RX FIFO due to an error condition. The code tries to clear both RXOK and RXNEMP but RXNEMP will not clear due to a frame still being in the FIFO. The frame will never be read from the FIFO as RXOK is no longer set. (b) A frame is received between xcan_rx_poll() reading interrupt status and clearing RXOK. RXOK will be cleared, but RXNEMP will again remain set as the new message is still in the FIFO. I'm able to trigger case (b) by flooding the bus with frames under load. There does not seem to be any benefit in using both RXNEMP and RXOK in the way the driver does, and the polling example in the reference manual (UG585 v1.10 18.3.7 Read Messages from RxFIFO) also says that either RXOK or RXNEMP can be used for detecting incoming messages. Fix the issue and simplify the RX processing by only using RXNEMP without RXOK. Tested with the integrated CAN on Zynq-7000 SoC. Fixes: b1201e44f50b ("can: xilinx CAN controller support") Signed-off-by: Anssi Hannula <anssi.hannula(a)bitwise.fi> Cc: <stable(a)vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl(a)pengutronix.de> --- drivers/net/can/xilinx_can.c | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-) diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index 389a9603db8c..1bda47aa62f5 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -101,7 +101,7 @@ enum xcan_reg { #define XCAN_INTR_ALL (XCAN_IXR_TXOK_MASK | XCAN_IXR_BSOFF_MASK |\ XCAN_IXR_WKUP_MASK | XCAN_IXR_SLP_MASK | \ XCAN_IXR_RXNEMP_MASK | XCAN_IXR_ERROR_MASK | \ - XCAN_IXR_ARBLST_MASK | XCAN_IXR_RXOK_MASK) + XCAN_IXR_ARBLST_MASK) /* CAN register bit shift - XCAN_<REG>_<BIT>_SHIFT */ #define XCAN_BTR_SJW_SHIFT 7 /* Synchronous jump width */ @@ -708,15 +708,7 @@ static int xcan_rx_poll(struct napi_struct *napi, int quota) isr = priv->read_reg(priv, XCAN_ISR_OFFSET); while ((isr & XCAN_IXR_RXNEMP_MASK) && (work_done < quota)) { - if (isr & XCAN_IXR_RXOK_MASK) { - priv->write_reg(priv, XCAN_ICR_OFFSET, - XCAN_IXR_RXOK_MASK); - work_done += xcan_rx(ndev); - } else { - priv->write_reg(priv, XCAN_ICR_OFFSET, - XCAN_IXR_RXNEMP_MASK); - break; - } + work_done += xcan_rx(ndev); priv->write_reg(priv, XCAN_ICR_OFFSET, XCAN_IXR_RXNEMP_MASK); isr = priv->read_reg(priv, XCAN_ISR_OFFSET); } @@ -727,7 +719,7 @@ static int xcan_rx_poll(struct napi_struct *napi, int quota) if (work_done < quota) { napi_complete_done(napi, work_done); ier = priv->read_reg(priv, XCAN_IER_OFFSET); - ier |= (XCAN_IXR_RXOK_MASK | XCAN_IXR_RXNEMP_MASK); + ier |= XCAN_IXR_RXNEMP_MASK; priv->write_reg(priv, XCAN_IER_OFFSET, ier); } return work_done; @@ -799,9 +791,9 @@ static irqreturn_t xcan_interrupt(int irq, void *dev_id) } /* Check for the type of receive interrupt and Processing it */ - if (isr & (XCAN_IXR_RXNEMP_MASK | XCAN_IXR_RXOK_MASK)) { + if (isr & XCAN_IXR_RXNEMP_MASK) { ier = priv->read_reg(priv, XCAN_IER_OFFSET); - ier &= ~(XCAN_IXR_RXNEMP_MASK | XCAN_IXR_RXOK_MASK); + ier &= ~XCAN_IXR_RXNEMP_MASK; priv->write_reg(priv, XCAN_IER_OFFSET, ier); napi_schedule(&priv->napi); } -- 2.18.0

7 years, 5 months

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[PATCH 06/12] can: xilinx_can: fix device dropping off bus on RX overrun

by Marc Kleine-Budde

From: Anssi Hannula <anssi.hannula(a)bitwise.fi> The xilinx_can driver performs a software reset when an RX overrun is detected. This causes the device to enter Configuration mode where no messages are received or transmitted. The documentation does not mention any need to perform a reset on an RX overrun, and testing by inducing an RX overflow also indicated that the device continues to work just fine without a reset. Remove the software reset. Tested with the integrated CAN on Zynq-7000 SoC. Fixes: b1201e44f50b ("can: xilinx CAN controller support") Signed-off-by: Anssi Hannula <anssi.hannula(a)bitwise.fi> Cc: <stable(a)vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl(a)pengutronix.de> --- drivers/net/can/xilinx_can.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index 89aec07c225f..389a9603db8c 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -600,7 +600,6 @@ static void xcan_err_interrupt(struct net_device *ndev, u32 isr) if (isr & XCAN_IXR_RXOFLW_MASK) { stats->rx_over_errors++; stats->rx_errors++; - priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK); if (skb) { cf->can_id |= CAN_ERR_CRTL; cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW; -- 2.18.0

7 years, 5 months

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[PATCH 04/12] can: m_can: Fix runtime resume call

by Marc Kleine-Budde

From: Faiz Abbas <faiz_abbas(a)ti.com> pm_runtime_get_sync() returns a 1 if the state of the device is already 'active'. This is not a failure case and should return a success. Therefore fix error handling for pm_runtime_get_sync() call such that it returns success when the value is 1. Also cleanup the TODO for using runtime PM for sleep mode as that is implemented. Signed-off-by: Faiz Abbas <faiz_abbas(a)ti.com> Cc: <stable(a)vger.kernel.org Signed-off-by: Marc Kleine-Budde <mkl(a)pengutronix.de> --- drivers/net/can/m_can/m_can.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 8e2b7f873c4d..e2f965c2e3aa 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -634,10 +634,12 @@ static int m_can_clk_start(struct m_can_priv *priv) int err; err = pm_runtime_get_sync(priv->device); - if (err) + if (err < 0) { pm_runtime_put_noidle(priv->device); + return err; + } - return err; + return 0; } static void m_can_clk_stop(struct m_can_priv *priv) @@ -1688,8 +1690,6 @@ static int m_can_plat_probe(struct platform_device *pdev) return ret; } -/* TODO: runtime PM with power down or sleep mode */ - static __maybe_unused int m_can_suspend(struct device *dev) { struct net_device *ndev = dev_get_drvdata(dev); -- 2.18.0

7 years, 5 months

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[PATCH 02/12] can: m_can.c: fix setup of CCCR register: clear CCCR NISO bit before checking can.ctrlmode

by Marc Kleine-Budde

From: Roman Fietze <roman.fietze(a)telemotive.de> Inside m_can_chip_config(), when setting up the new value of the CCCR, the CCCR_NISO bit is not cleared like the others, CCCR_TEST, CCCR_MON, CCCR_BRSE and CCCR_FDOE, before checking the can.ctrlmode bits for CAN_CTRLMODE_FD_NON_ISO. This way once the controller was configured for CAN_CTRLMODE_FD_NON_ISO, this mode could never be cleared again. This fix is only relevant for controllers with version 3.1.x or 3.2.x. Older versions do not support NISO. Signed-off-by: Roman Fietze <roman.fietze(a)telemotive.de> Cc: linux-stable <stable(a)vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl(a)pengutronix.de> --- drivers/net/can/m_can/m_can.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index b397a33f3d32..8e2b7f873c4d 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1109,7 +1109,8 @@ static void m_can_chip_config(struct net_device *dev) } else { /* Version 3.1.x or 3.2.x */ - cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_BRSE | CCCR_FDOE); + cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_BRSE | CCCR_FDOE | + CCCR_NISO); /* Only 3.2.x has NISO Bit implemented */ if (priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO) -- 2.18.0

7 years, 5 months

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