Linaro-mm-sig

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2915 discussions

Re: [Linaro-mm-sig] [PATCH v2] i2c: tegra: Add ACPI support

by Dmitry Osipenko

23.11.2021 10:15, Akhil R пишет: > Add support for ACPI based device registration so that the driver > can be also enabled through ACPI table. > > Signed-off-by: Akhil R <akhilrajeev(a)nvidia.com> > --- > drivers/i2c/busses/i2c-tegra.c | 52 ++++++++++++++++++++++++++++++++---------- > 1 file changed, 40 insertions(+), 12 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c > index c883044..8e47889 100644 > --- a/drivers/i2c/busses/i2c-tegra.c > +++ b/drivers/i2c/busses/i2c-tegra.c > @@ -6,6 +6,7 @@ > * Author: Colin Cross <ccross(a)android.com> > */ > > +#include <linux/acpi.h> > #include <linux/bitfield.h> > #include <linux/clk.h> > #include <linux/delay.h> > @@ -608,6 +609,7 @@ static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev) > static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) > { > u32 val, clk_divisor, clk_multiplier, tsu_thd, tlow, thigh, non_hs_mode; > + acpi_handle handle = ACPI_HANDLE(i2c_dev->dev); > int err; > > /* > @@ -618,7 +620,11 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) > * emit a noisy warning on error, which won't stay unnoticed and > * won't hose machine entirely. > */ > - err = reset_control_reset(i2c_dev->rst); > + if (handle && acpi_has_method(handle, "_RST")) Which SoC version doesn't have "_RST" method? If neither, then please remove this check. > + err = (acpi_evaluate_object(handle, "_RST", NULL, NULL)); Please remove parens around acpi_evaluate_object(). Why you added them? > + else > + err = reset_control_reset(i2c_dev->rst); > + > WARN_ON_ONCE(err); > > if (i2c_dev->is_dvc) > @@ -1627,12 +1633,12 @@ static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev) > bool multi_mode; > int err; > > - err = of_property_read_u32(np, "clock-frequency", > - &i2c_dev->bus_clk_rate); > + err = device_property_read_u32(i2c_dev->dev, "clock-frequency", > + &i2c_dev->bus_clk_rate); > if (err) > i2c_dev->bus_clk_rate = I2C_MAX_STANDARD_MODE_FREQ; > > - multi_mode = of_property_read_bool(np, "multi-master"); > + multi_mode = device_property_read_bool(i2c_dev->dev, "multi-master"); > i2c_dev->multimaster_mode = multi_mode; > > if (of_device_is_compatible(np, "nvidia,tegra20-i2c-dvc")) > @@ -1642,10 +1648,25 @@ static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev) > i2c_dev->is_vi = true; > } How are you going to differentiate the VI I2C from a non-VI? This doesn't look right. > > +static int tegra_i2c_init_reset(struct tegra_i2c_dev *i2c_dev) > +{ > + if (has_acpi_companion(i2c_dev->dev)) > + return 0; > + > + i2c_dev->rst = devm_reset_control_get_exclusive(i2c_dev->dev, "i2c"); > + if (IS_ERR(i2c_dev->rst)) > + return PTR_ERR(i2c_dev->rst); > + > + return 0; > +} > + > static int tegra_i2c_init_clocks(struct tegra_i2c_dev *i2c_dev) > { > int err; > > + if (has_acpi_companion(i2c_dev->dev)) > + return 0; > + > i2c_dev->clocks[i2c_dev->nclocks++].id = "div-clk"; > > if (i2c_dev->hw == &tegra20_i2c_hw || i2c_dev->hw == &tegra30_i2c_hw) > @@ -1720,7 +1741,7 @@ static int tegra_i2c_probe(struct platform_device *pdev) > init_completion(&i2c_dev->msg_complete); > init_completion(&i2c_dev->dma_complete); > > - i2c_dev->hw = of_device_get_match_data(&pdev->dev); > + i2c_dev->hw = device_get_match_data(&pdev->dev); > i2c_dev->cont_id = pdev->id; > i2c_dev->dev = &pdev->dev; > > @@ -1746,15 +1767,13 @@ static int tegra_i2c_probe(struct platform_device *pdev) > if (err) > return err; > > - i2c_dev->rst = devm_reset_control_get_exclusive(i2c_dev->dev, "i2c"); > - if (IS_ERR(i2c_dev->rst)) { > - dev_err_probe(i2c_dev->dev, PTR_ERR(i2c_dev->rst), > - "failed to get reset control\n"); > - return PTR_ERR(i2c_dev->rst); > - } > - > tegra_i2c_parse_dt(i2c_dev); > > + err = tegra_i2c_init_reset(i2c_dev); > + if (err) > + return dev_err_probe(i2c_dev->dev, err, > + "failed to get reset control\n"); This is inconsistent with tegra_i2c_init_clocks() which returns err directly and prints error message within the function. Please move the dev_err_probe() into tegra_i2c_init_reset() to make it consistent, like I suggested before. Please don't reply with a new version of the patch to the old thread, always send a new version separately. Otherwise it's more difficult to follow patches. Lastly, each new version of a patch must contain changelog. I don't see changelog here, please add it to v3 after the " ---" separator of the commit message. Thanks! Example: Commit message. Signed-off-by: Akhil R <akhilrajeev(a)nvidia.com> --- drivers/i2c/busses/i2c-tegra.c | 52 ++++++++++++++++++++++++++++++++---------- 1 file changed, 40 insertions(+), 12 deletions(-) Changelog: v3: bla-bla-bla v2: bla-bla-bla diff ...

3 years, 7 months

Re: [Linaro-mm-sig] [PATCH v2] i2c: tegra: Add ACPI support

by kernel test robot

Hi Akhil, Thank you for the patch! Yet something to improve: [auto build test ERROR on tegra/for-next] [also build test ERROR on v5.16-rc2 next-20211123] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Akhil-R/i2c-tegra-Add-ACPI-support… base: https://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux.git for-next config: m68k-randconfig-r011-20211123 (https://download.01.org/0day-ci/archive/20211123/202111232153.mpoejDRV-lkp@…) compiler: m68k-linux-gcc (GCC) 11.2.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/0day-ci/linux/commit/dec174be801f41a9e42f4381c59c2357c25… git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Akhil-R/i2c-tegra-Add-ACPI-support/20211123-151636 git checkout dec174be801f41a9e42f4381c59c2357c25e40fb # save the config file to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=m68k If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com> All errors (new ones prefixed by >>): drivers/i2c/busses/i2c-tegra.c: In function 'tegra_i2c_init': >> drivers/i2c/busses/i2c-tegra.c:623:23: error: implicit declaration of function 'acpi_has_method'; did you mean 'acpi_has_watchdog'? [-Werror=implicit-function-declaration] 623 | if (handle && acpi_has_method(handle, "_RST")) | ^~~~~~~~~~~~~~~ | acpi_has_watchdog cc1: some warnings being treated as errors vim +623 drivers/i2c/busses/i2c-tegra.c 608 609 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) 610 { 611 u32 val, clk_divisor, clk_multiplier, tsu_thd, tlow, thigh, non_hs_mode; 612 acpi_handle handle = ACPI_HANDLE(i2c_dev->dev); 613 int err; 614 615 /* 616 * The reset shouldn't ever fail in practice. The failure will be a 617 * sign of a severe problem that needs to be resolved. Still we don't 618 * want to fail the initialization completely because this may break 619 * kernel boot up since voltage regulators use I2C. Hence, we will 620 * emit a noisy warning on error, which won't stay unnoticed and 621 * won't hose machine entirely. 622 */ > 623 if (handle && acpi_has_method(handle, "_RST")) 624 err = (acpi_evaluate_object(handle, "_RST", NULL, NULL)); 625 else 626 err = reset_control_reset(i2c_dev->rst); 627 628 WARN_ON_ONCE(err); 629 630 if (i2c_dev->is_dvc) 631 tegra_dvc_init(i2c_dev); 632 633 val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN | 634 FIELD_PREP(I2C_CNFG_DEBOUNCE_CNT, 2); 635 636 if (i2c_dev->hw->has_multi_master_mode) 637 val |= I2C_CNFG_MULTI_MASTER_MODE; 638 639 i2c_writel(i2c_dev, val, I2C_CNFG); 640 i2c_writel(i2c_dev, 0, I2C_INT_MASK); 641 642 if (i2c_dev->is_vi) 643 tegra_i2c_vi_init(i2c_dev); 644 645 switch (i2c_dev->bus_clk_rate) { 646 case I2C_MAX_STANDARD_MODE_FREQ + 1 ... I2C_MAX_FAST_MODE_PLUS_FREQ: 647 default: 648 tlow = i2c_dev->hw->tlow_fast_fastplus_mode; 649 thigh = i2c_dev->hw->thigh_fast_fastplus_mode; 650 tsu_thd = i2c_dev->hw->setup_hold_time_fast_fast_plus_mode; 651 652 if (i2c_dev->bus_clk_rate > I2C_MAX_FAST_MODE_FREQ) 653 non_hs_mode = i2c_dev->hw->clk_divisor_fast_plus_mode; 654 else 655 non_hs_mode = i2c_dev->hw->clk_divisor_fast_mode; 656 break; 657 658 case 0 ... I2C_MAX_STANDARD_MODE_FREQ: 659 tlow = i2c_dev->hw->tlow_std_mode; 660 thigh = i2c_dev->hw->thigh_std_mode; 661 tsu_thd = i2c_dev->hw->setup_hold_time_std_mode; 662 non_hs_mode = i2c_dev->hw->clk_divisor_std_mode; 663 break; 664 } 665 666 /* make sure clock divisor programmed correctly */ 667 clk_divisor = FIELD_PREP(I2C_CLK_DIVISOR_HSMODE, 668 i2c_dev->hw->clk_divisor_hs_mode) | 669 FIELD_PREP(I2C_CLK_DIVISOR_STD_FAST_MODE, non_hs_mode); 670 i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR); 671 672 if (i2c_dev->hw->has_interface_timing_reg) { 673 val = FIELD_PREP(I2C_INTERFACE_TIMING_THIGH, thigh) | 674 FIELD_PREP(I2C_INTERFACE_TIMING_TLOW, tlow); 675 i2c_writel(i2c_dev, val, I2C_INTERFACE_TIMING_0); 676 } 677 678 /* 679 * Configure setup and hold times only when tsu_thd is non-zero. 680 * Otherwise, preserve the chip default values. 681 */ 682 if (i2c_dev->hw->has_interface_timing_reg && tsu_thd) 683 i2c_writel(i2c_dev, tsu_thd, I2C_INTERFACE_TIMING_1); 684 685 clk_multiplier = (tlow + thigh + 2) * (non_hs_mode + 1); 686 687 err = clk_set_rate(i2c_dev->div_clk, 688 i2c_dev->bus_clk_rate * clk_multiplier); 689 if (err) { 690 dev_err(i2c_dev->dev, "failed to set div-clk rate: %d\n", err); 691 return err; 692 } 693 694 if (!i2c_dev->is_dvc && !i2c_dev->is_vi) { 695 u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG); 696 697 sl_cfg |= I2C_SL_CNFG_NACK | I2C_SL_CNFG_NEWSL; 698 i2c_writel(i2c_dev, sl_cfg, I2C_SL_CNFG); 699 i2c_writel(i2c_dev, 0xfc, I2C_SL_ADDR1); 700 i2c_writel(i2c_dev, 0x00, I2C_SL_ADDR2); 701 } 702 703 err = tegra_i2c_flush_fifos(i2c_dev); 704 if (err) 705 return err; 706 707 if (i2c_dev->multimaster_mode && i2c_dev->hw->has_slcg_override_reg) 708 i2c_writel(i2c_dev, I2C_MST_CORE_CLKEN_OVR, I2C_CLKEN_OVERRIDE); 709 710 err = tegra_i2c_wait_for_config_load(i2c_dev); 711 if (err) 712 return err; 713 714 return 0; 715 } 716 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

3 years, 7 months

Re: [Linaro-mm-sig] [PATCH 01/15] iio: buffer-dma: Get rid of incoming/outgoing queues

by Lars-Peter Clausen

On 11/22/21 4:16 PM, Paul Cercueil wrote: > Hi Lars, > > Le lun., nov. 22 2021 at 16:08:51 +0100, Lars-Peter Clausen > <lars(a)metafoo.de> a écrit : >> On 11/21/21 9:08 PM, Paul Cercueil wrote: >>> >>> >>> Le dim., nov. 21 2021 at 19:49:03 +0100, Lars-Peter Clausen >>> <lars(a)metafoo.de> a écrit : >>>> On 11/21/21 6:52 PM, Paul Cercueil wrote: >>>>> Hi Lars, >>>>> >>>>> Le dim., nov. 21 2021 at 17:23:35 +0100, Lars-Peter Clausen >>>>> <lars(a)metafoo.de> a écrit : >>>>>> On 11/15/21 3:19 PM, Paul Cercueil wrote: >>>>>>> The buffer-dma code was using two queues, incoming and outgoing, to >>>>>>> manage the state of the blocks in use. >>>>>>> >>>>>>> While this totally works, it adds some complexity to the code, >>>>>>> especially since the code only manages 2 blocks. It is much >>>>>>> easier to >>>>>>> just check each block's state manually, and keep a counter for >>>>>>> the next >>>>>>> block to dequeue. >>>>>>> >>>>>>> Since the new DMABUF based API wouldn't use these incoming and >>>>>>> outgoing >>>>>>> queues anyway, getting rid of them now makes the upcoming changes >>>>>>> simpler. >>>>>>> >>>>>>> Signed-off-by: Paul Cercueil <paul(a)crapouillou.net> >>>>>> The outgoing queue is going to be replaced by fences, but I think >>>>>> we need to keep the incoming queue. >>>>> >>>>> Blocks are always accessed in sequential order, so we now have a >>>>> "queue->next_dequeue" that cycles between the buffers >>>>> allocated for fileio. >>>>> >>>>>>> [...] >>>>>>> @@ -442,28 +435,33 @@ EXPORT_SYMBOL_GPL(iio_dma_buffer_disable); >>>>>>> static void iio_dma_buffer_enqueue(struct iio_dma_buffer_queue >>>>>>> *queue, >>>>>>> struct iio_dma_buffer_block *block) >>>>>>> { >>>>>>> - if (block->state == IIO_BLOCK_STATE_DEAD) { >>>>>>> + if (block->state == IIO_BLOCK_STATE_DEAD) >>>>>>> iio_buffer_block_put(block); >>>>>>> - } else if (queue->active) { >>>>>>> + else if (queue->active) >>>>>>> iio_dma_buffer_submit_block(queue, block); >>>>>>> - } else { >>>>>>> + else >>>>>>> block->state = IIO_BLOCK_STATE_QUEUED; >>>>>>> - list_add_tail(&block->head, &queue->incoming); >>>>>> If iio_dma_buffer_enqueue() is called with a dmabuf and the >>>>>> buffer is not active, it will be marked as queued, but we >>>>>> don't actually keep a reference to it anywhere. It will >>>>>> never be submitted to the DMA, and it will never be >>>>>> signaled as completed. >>>>> >>>>> We do keep a reference to the buffers, in the queue->fileio.blocks >>>>> array. When the buffer is enabled, all the blocks in that >>>>> array that are in the "queued" state will be submitted to the >>>>> DMA. >>>>> >>>> But not when used in combination with the DMA buf changes later in >>>> this series. >>>> >>> >>> That's still the case after the DMABUF changes of the series. Or can >>> you point me exactly what you think is broken? >>> >> When you allocate a DMABUF with the allocate IOCTL and then submit it >> with the enqueue IOCTL before the buffer is enabled it will end up >> marked as queued, but not actually be queued anywhere. >> > > Ok, it works for me because I never enqueue blocks before enabling the > buffer. I can add a requirement that blocks must be enqueued only > after the buffer is enabled. I don't think that is a good idea. This way you are going to potentially drop data at the begining of your stream when the DMA isn't ready yet.

3 years, 7 months

Re: [Linaro-mm-sig] [PATCH 01/15] iio: buffer-dma: Get rid of incoming/outgoing queues

by Lars-Peter Clausen

On 11/21/21 9:08 PM, Paul Cercueil wrote: > > > Le dim., nov. 21 2021 at 19:49:03 +0100, Lars-Peter Clausen > <lars(a)metafoo.de> a écrit : >> On 11/21/21 6:52 PM, Paul Cercueil wrote: >>> Hi Lars, >>> >>> Le dim., nov. 21 2021 at 17:23:35 +0100, Lars-Peter Clausen >>> <lars(a)metafoo.de> a écrit : >>>> On 11/15/21 3:19 PM, Paul Cercueil wrote: >>>>> The buffer-dma code was using two queues, incoming and outgoing, to >>>>> manage the state of the blocks in use. >>>>> >>>>> While this totally works, it adds some complexity to the code, >>>>> especially since the code only manages 2 blocks. It is much easier to >>>>> just check each block's state manually, and keep a counter for the >>>>> next >>>>> block to dequeue. >>>>> >>>>> Since the new DMABUF based API wouldn't use these incoming and >>>>> outgoing >>>>> queues anyway, getting rid of them now makes the upcoming changes >>>>> simpler. >>>>> >>>>> Signed-off-by: Paul Cercueil <paul(a)crapouillou.net> >>>> The outgoing queue is going to be replaced by fences, but I think >>>> we need to keep the incoming queue. >>> >>> Blocks are always accessed in sequential order, so we now have a >>> "queue->next_dequeue" that cycles between the buffers allocated for >>> fileio. >>> >>>>> [...] >>>>> @@ -442,28 +435,33 @@ EXPORT_SYMBOL_GPL(iio_dma_buffer_disable); >>>>> static void iio_dma_buffer_enqueue(struct iio_dma_buffer_queue >>>>> *queue, >>>>> struct iio_dma_buffer_block *block) >>>>> { >>>>> - if (block->state == IIO_BLOCK_STATE_DEAD) { >>>>> + if (block->state == IIO_BLOCK_STATE_DEAD) >>>>> iio_buffer_block_put(block); >>>>> - } else if (queue->active) { >>>>> + else if (queue->active) >>>>> iio_dma_buffer_submit_block(queue, block); >>>>> - } else { >>>>> + else >>>>> block->state = IIO_BLOCK_STATE_QUEUED; >>>>> - list_add_tail(&block->head, &queue->incoming); >>>> If iio_dma_buffer_enqueue() is called with a dmabuf and the buffer >>>> is not active, it will be marked as queued, but we don't actually >>>> keep a reference to it anywhere. It will never be submitted to >>>> the DMA, and it will never be signaled as completed. >>> >>> We do keep a reference to the buffers, in the queue->fileio.blocks >>> array. When the buffer is enabled, all the blocks in that array >>> that are in the "queued" state will be submitted to the DMA. >>> >> But not when used in combination with the DMA buf changes later in >> this series. >> > > That's still the case after the DMABUF changes of the series. Or can > you point me exactly what you think is broken? > When you allocate a DMABUF with the allocate IOCTL and then submit it with the enqueue IOCTL before the buffer is enabled it will end up marked as queued, but not actually be queued anywhere.

3 years, 7 months

Re: [Linaro-mm-sig] [PATCH] i2c: tegra: Add ACPI support

by Dmitry Osipenko

19.11.2021 16:32, Akhil R пишет: > - i2c_dev->rst = devm_reset_control_get_exclusive(i2c_dev->dev, "i2c"); > - if (IS_ERR(i2c_dev->rst)) { > - dev_err_probe(i2c_dev->dev, PTR_ERR(i2c_dev->rst), > - "failed to get reset control\n"); > - return PTR_ERR(i2c_dev->rst); > - } > - > tegra_i2c_parse_dt(i2c_dev); > > - err = tegra_i2c_init_clocks(i2c_dev); > - if (err) > - return err; > + if (!has_acpi_companion(&pdev->dev)) { > + i2c_dev->rst = devm_reset_control_get_exclusive(i2c_dev->dev, "i2c"); > + if (IS_ERR(i2c_dev->rst)) { > + dev_err_probe(i2c_dev->dev, PTR_ERR(i2c_dev->rst), > + "failed to get reset control\n"); > + return PTR_ERR(i2c_dev->rst); > + } > + > + err = tegra_i2c_init_clocks(i2c_dev); > + if (err) > + return err; > + } What about to factor out the reset initialization into a separate function and write it like this: static int tegra_i2c_init_reset(i2c_dev) { if (has_acpi_companion(i2c_dev->dev) return 0; i2c_dev->rst = devm_reset_control_get_exclusive(i2c_dev->dev, "i2c"); if (IS_ERR(i2c_dev->rst)) return dev_err_probe(i2c_dev->dev, PTR_ERR(i2c_dev->rst), "failed to get reset control\n"); return 0; } And then change tegra_i2c_init_clocks() to: static int tegra_i2c_init_clocks(i2c_dev) { int err; if (has_acpi_companion(i2c_dev->dev)) return 0; ... } This will make both reset/clocks initialization to look more consistent.

3 years, 7 months

Re: [Linaro-mm-sig] [PATCH] i2c: tegra: Add ACPI support

by Dmitry Osipenko

19.11.2021 17:48, Andy Shevchenko пишет: >> + if (i2c_dev->nclocks == 0) >> + return; > Why? Make clocks optional. This check shouldn't be needed because both clk_disable() and clk_bulk_unprepare() should handle NULL/zero clocks without problems.

3 years, 7 months

Re: [Linaro-mm-sig] [PATCH 01/15] iio: buffer-dma: Get rid of incoming/outgoing queues

by Lars-Peter Clausen

On 11/21/21 6:52 PM, Paul Cercueil wrote: > Hi Lars, > > Le dim., nov. 21 2021 at 17:23:35 +0100, Lars-Peter Clausen > <lars(a)metafoo.de> a écrit : >> On 11/15/21 3:19 PM, Paul Cercueil wrote: >>> The buffer-dma code was using two queues, incoming and outgoing, to >>> manage the state of the blocks in use. >>> >>> While this totally works, it adds some complexity to the code, >>> especially since the code only manages 2 blocks. It is much easier to >>> just check each block's state manually, and keep a counter for the next >>> block to dequeue. >>> >>> Since the new DMABUF based API wouldn't use these incoming and outgoing >>> queues anyway, getting rid of them now makes the upcoming changes >>> simpler. >>> >>> Signed-off-by: Paul Cercueil <paul(a)crapouillou.net> >> The outgoing queue is going to be replaced by fences, but I think we >> need to keep the incoming queue. > > Blocks are always accessed in sequential order, so we now have a > "queue->next_dequeue" that cycles between the buffers allocated for > fileio. > >>> [...] >>> @@ -442,28 +435,33 @@ EXPORT_SYMBOL_GPL(iio_dma_buffer_disable); >>> static void iio_dma_buffer_enqueue(struct iio_dma_buffer_queue >>> *queue, >>> struct iio_dma_buffer_block *block) >>> { >>> - if (block->state == IIO_BLOCK_STATE_DEAD) { >>> + if (block->state == IIO_BLOCK_STATE_DEAD) >>> iio_buffer_block_put(block); >>> - } else if (queue->active) { >>> + else if (queue->active) >>> iio_dma_buffer_submit_block(queue, block); >>> - } else { >>> + else >>> block->state = IIO_BLOCK_STATE_QUEUED; >>> - list_add_tail(&block->head, &queue->incoming); >> If iio_dma_buffer_enqueue() is called with a dmabuf and the buffer is >> not active, it will be marked as queued, but we don't actually keep a >> reference to it anywhere. It will never be submitted to the DMA, and >> it will never be signaled as completed. > > We do keep a reference to the buffers, in the queue->fileio.blocks > array. When the buffer is enabled, all the blocks in that array that > are in the "queued" state will be submitted to the DMA. > But not when used in combination with the DMA buf changes later in this series.

3 years, 7 months

Re: [Linaro-mm-sig] [PATCH 01/15] iio: buffer-dma: Get rid of incoming/outgoing queues

by Lars-Peter Clausen

On 11/15/21 3:19 PM, Paul Cercueil wrote: > The buffer-dma code was using two queues, incoming and outgoing, to > manage the state of the blocks in use. > > While this totally works, it adds some complexity to the code, > especially since the code only manages 2 blocks. It is much easier to > just check each block's state manually, and keep a counter for the next > block to dequeue. > > Since the new DMABUF based API wouldn't use these incoming and outgoing > queues anyway, getting rid of them now makes the upcoming changes > simpler. > > Signed-off-by: Paul Cercueil <paul(a)crapouillou.net> The outgoing queue is going to be replaced by fences, but I think we need to keep the incoming queue. > [...] > @@ -442,28 +435,33 @@ EXPORT_SYMBOL_GPL(iio_dma_buffer_disable); > static void iio_dma_buffer_enqueue(struct iio_dma_buffer_queue *queue, > struct iio_dma_buffer_block *block) > { > - if (block->state == IIO_BLOCK_STATE_DEAD) { > + if (block->state == IIO_BLOCK_STATE_DEAD) > iio_buffer_block_put(block); > - } else if (queue->active) { > + else if (queue->active) > iio_dma_buffer_submit_block(queue, block); > - } else { > + else > block->state = IIO_BLOCK_STATE_QUEUED; > - list_add_tail(&block->head, &queue->incoming); If iio_dma_buffer_enqueue() is called with a dmabuf and the buffer is not active, it will be marked as queued, but we don't actually keep a reference to it anywhere. It will never be submitted to the DMA, and it will never be signaled as completed.

3 years, 7 months

Re: [Linaro-mm-sig] [PATCH 00/15] iio: buffer-dma: write() and new DMABUF based API

by Christian König

Am 16.11.21 um 17:31 schrieb Laurent Pinchart: > On Tue, Nov 16, 2021 at 05:02:25PM +0100, Daniel Vetter wrote: >> On Mon, Nov 15, 2021 at 02:57:37PM +0000, Paul Cercueil wrote: >>> Le lun., nov. 15 2021 at 15:37:16 +0100, Daniel Vetter a écrit : >>>> On Mon, Nov 15, 2021 at 02:19:10PM +0000, Paul Cercueil wrote: >>>>> Hi Jonathan, >>>>> >>>>> This patchset introduces a new userspace interface based on DMABUF >>>>> objects, to complement the existing fileio based API. >>>>> >>>>> The advantage of this DMABUF based interface vs. the fileio >>>>> interface, is that it avoids an extra copy of the data between the >>>>> kernel and userspace. This is particularly userful for high-speed >>>>> devices which produce several megabytes or even gigabytes of data per >>>>> second. >>>>> >>>>> The first few patches [01/15] to [03/15] are not really related, but >>>>> allow to reduce the size of the patches that introduce the new API. >>>>> >>>>> Patch [04/15] to [06/15] enables write() support to the buffer-dma >>>>> implementation of the buffer API, to continue the work done by >>>>> Mihail Chindris. >>>>> >>>>> Patches [07/15] to [12/15] introduce the new DMABUF based API. >>>>> >>>>> Patches [13/15] and [14/15] add support for cyclic buffers, only through >>>>> the new API. A cyclic buffer will be repeated on the output until the >>>>> buffer is disabled. >>>>> >>>>> Patch [15/15] adds documentation about the new API. >>>>> >>>>> For now, the API allows you to alloc DMABUF objects and mmap() them >>>>> to >>>>> read or write the samples. It does not yet allow to import DMABUFs >>>>> parented to other subsystems, but that should eventually be possible >>>>> once it's wired. >>>>> >>>>> This patchset is inspired by the "mmap interface" that was previously >>>>> submitted by Alexandru Ardelean and Lars-Peter Clausen, so it would be >>>>> great if I could get a review from you guys. Alexandru's commit was >>>>> signed with his @analog.com address but he doesn't work at ADI anymore, >>>>> so I believe I'll need him to sign with a new email. >>>> Why dma-buf? dma-buf looks like something super generic and useful, until >>>> you realize that there's a metric ton of gpu/accelerator bagage piled in. >>>> So unless buffer sharing with a gpu/video/accel/whatever device is the > And cameras (maybe they're included in "whatever" ?). > >>>> goal here, and it's just for a convenient way to get at buffer handles, >>>> this doesn't sound like a good idea. >>> Good question. The first reason is that a somewhat similar API was intented >>> before[1], but refused upstream as it was kind of re-inventing the wheel. >>> >>> The second reason, is that we want to be able to share buffers too, not with >>> gpu/video but with the network (zctap) and in the future with USB >>> (functionFS) too. >>> >>> [1]: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kern… >> Hm is that code merged already in upstream already? >> >> I know that dma-buf looks really generic, but like I said if there's no >> need ever to interface with any of the gpu buffer sharing it might be >> better to use something else (like get_user_pages maybe, would that work?). > Not GUP please. That brings another set of issues, especially when > dealing with DMA, we've suffered enough from the USERPTR support in V4L2 > to avoid repeating this. Let's make dma-buf better instead. Yeah, when comparing GUP and DMA-buf the later is clearly the lesser evil. DMA-buf indeed has some design issues we need to work on, especially around the async operations and synchronization. But I still think those are solvable. GUP on the other hand has some hard fundamental problems which you can only solved completely if the hardware is capable of fast and reliable recoverable page faults. Regards, Christian.

3 years, 7 months

Re: [Linaro-mm-sig] [PATCH 00/15] iio: buffer-dma: write() and new DMABUF based API

by Daniel Vetter

On Mon, Nov 15, 2021 at 02:57:37PM +0000, Paul Cercueil wrote: > Hi Daniel, > > Le lun., nov. 15 2021 at 15:37:16 +0100, Daniel Vetter <daniel(a)ffwll.ch> a > écrit : > > On Mon, Nov 15, 2021 at 02:19:10PM +0000, Paul Cercueil wrote: > > > Hi Jonathan, > > > > > > This patchset introduces a new userspace interface based on DMABUF > > > objects, to complement the existing fileio based API. > > > > > > The advantage of this DMABUF based interface vs. the fileio > > > interface, is that it avoids an extra copy of the data between the > > > kernel and userspace. This is particularly userful for high-speed > > > devices which produce several megabytes or even gigabytes of data > > > per > > > second. > > > > > > The first few patches [01/15] to [03/15] are not really related, but > > > allow to reduce the size of the patches that introduce the new API. > > > > > > Patch [04/15] to [06/15] enables write() support to the buffer-dma > > > implementation of the buffer API, to continue the work done by > > > Mihail Chindris. > > > > > > Patches [07/15] to [12/15] introduce the new DMABUF based API. > > > > > > Patches [13/15] and [14/15] add support for cyclic buffers, only > > > through > > > the new API. A cyclic buffer will be repeated on the output until > > > the > > > buffer is disabled. > > > > > > Patch [15/15] adds documentation about the new API. > > > > > > For now, the API allows you to alloc DMABUF objects and mmap() them > > > to > > > read or write the samples. It does not yet allow to import DMABUFs > > > parented to other subsystems, but that should eventually be possible > > > once it's wired. > > > > > > This patchset is inspired by the "mmap interface" that was > > > previously > > > submitted by Alexandru Ardelean and Lars-Peter Clausen, so it would > > > be > > > great if I could get a review from you guys. Alexandru's commit was > > > signed with his @analog.com address but he doesn't work at ADI > > > anymore, > > > so I believe I'll need him to sign with a new email. > > > > Why dma-buf? dma-buf looks like something super generic and useful, > > until > > you realize that there's a metric ton of gpu/accelerator bagage piled > > in. > > So unless buffer sharing with a gpu/video/accel/whatever device is the > > goal here, and it's just for a convenient way to get at buffer handles, > > this doesn't sound like a good idea. > > Good question. The first reason is that a somewhat similar API was intented > before[1], but refused upstream as it was kind of re-inventing the wheel. > > The second reason, is that we want to be able to share buffers too, not with > gpu/video but with the network (zctap) and in the future with USB > (functionFS) too. > > [1]: https://lore.kernel.org/linux-iio/20210217073638.21681-1-alexandru.ardelean… Hm is that code merged already in upstream already? I know that dma-buf looks really generic, but like I said if there's no need ever to interface with any of the gpu buffer sharing it might be better to use something else (like get_user_pages maybe, would that work?). > > Also if the idea is to this with gpus/accelerators then I'd really like > > to > > see the full thing, since most likely at that point you also want > > dma_fence. And once we talk dma_fence things get truly horrible from a > > locking pov :-( Or well, just highly constrained and I get to review > > what > > iio is doing with these buffers to make sure it all fits. > > There is some dma_fence action in patch #10, which is enough for the > userspace apps to use the API. > > What "horribleness" are we talking about here? It doesn't look that scary to > me, but I certainly don't have the complete picture. You need to annotate all the code involved in signalling that dma_fence using dma_fence_begin/end_signalling, and then enable full lockdep and everything. You can safely assume you'll find bugs, because we even have bugs about this in gpu drivers (where that annotation isn't fully rolled out yet). The tldr is that you can allocate memory in there. And a pile of other restrictions, but not being able to allocate memory (well GFP_ATOMIC is ok, but that can fail) is a very serious restriction. -Daniel > > Cheers, > -Paul > > > Cheers, Daniel > > > > > > > > Cheers, > > > -Paul > > > > > > Alexandru Ardelean (1): > > > iio: buffer-dma: split iio_dma_buffer_fileio_free() function > > > > > > Paul Cercueil (14): > > > iio: buffer-dma: Get rid of incoming/outgoing queues > > > iio: buffer-dma: Remove unused iio_buffer_block struct > > > iio: buffer-dma: Use round_down() instead of rounddown() > > > iio: buffer-dma: Enable buffer write support > > > iio: buffer-dmaengine: Support specifying buffer direction > > > iio: buffer-dmaengine: Enable write support > > > iio: core: Add new DMABUF interface infrastructure > > > iio: buffer-dma: Use DMABUFs instead of custom solution > > > iio: buffer-dma: Implement new DMABUF based userspace API > > > iio: buffer-dma: Boost performance using write-combine cache > > > setting > > > iio: buffer-dmaengine: Support new DMABUF based userspace API > > > iio: core: Add support for cyclic buffers > > > iio: buffer-dmaengine: Add support for cyclic buffers > > > Documentation: iio: Document high-speed DMABUF based API > > > > > > Documentation/driver-api/dma-buf.rst | 2 + > > > Documentation/iio/dmabuf_api.rst | 94 +++ > > > Documentation/iio/index.rst | 2 + > > > drivers/iio/adc/adi-axi-adc.c | 3 +- > > > drivers/iio/buffer/industrialio-buffer-dma.c | 670 > > > ++++++++++++++---- > > > .../buffer/industrialio-buffer-dmaengine.c | 42 +- > > > drivers/iio/industrialio-buffer.c | 49 ++ > > > include/linux/iio/buffer-dma.h | 43 +- > > > include/linux/iio/buffer-dmaengine.h | 5 +- > > > include/linux/iio/buffer_impl.h | 8 + > > > include/uapi/linux/iio/buffer.h | 30 + > > > 11 files changed, 783 insertions(+), 165 deletions(-) > > > create mode 100644 Documentation/iio/dmabuf_api.rst > > > > > > -- > > > 2.33.0 > > > > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > http://blog.ffwll.ch > > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch

3 years, 7 months

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