The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ea4c1787685dbf9842046f05b6390b6901ee6ba2 Mon Sep 17 00:00:00 2001
From: Matthias Schiffer matthias.schiffer@ew.tq-group.com Date: Mon, 15 Nov 2021 10:18:52 +0100 Subject: [PATCH] can: m_can: pci: use custom bit timings for Elkhart Lake MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
The relevant datasheet [1] specifies nonstandard limits for the bit timing parameters. While it is unclear what the exact effect of violating these limits is, it seems like a good idea to adhere to the documentation.
[1] Intel Atom® x6000E Series, and Intel® Pentium® and Celeron® N and J Series Processors for IoT Applications Datasheet, Volume 2 (Book 3 of 3), July 2021, Revision 001
Fixes: cab7ffc0324f ("can: m_can: add PCI glue driver for Intel Elkhart Lake") Link: https://lore.kernel.org/all/9eba5d7c05a48ead4024ffa6e5926f191d8c6b38.1636967... Signed-off-by: Matthias Schiffer matthias.schiffer@ew.tq-group.com Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de
diff --git a/drivers/net/can/m_can/m_can_pci.c b/drivers/net/can/m_can/m_can_pci.c index 8f184a852a0a..b56a54d6c5a9 100644 --- a/drivers/net/can/m_can/m_can_pci.c +++ b/drivers/net/can/m_can/m_can_pci.c @@ -18,9 +18,14 @@
#define M_CAN_PCI_MMIO_BAR 0
-#define M_CAN_CLOCK_FREQ_EHL 200000000 #define CTL_CSR_INT_CTL_OFFSET 0x508
+struct m_can_pci_config { + const struct can_bittiming_const *bit_timing; + const struct can_bittiming_const *data_timing; + unsigned int clock_freq; +}; + struct m_can_pci_priv { struct m_can_classdev cdev;
@@ -84,9 +89,40 @@ static struct m_can_ops m_can_pci_ops = { .read_fifo = iomap_read_fifo, };
+static const struct can_bittiming_const m_can_bittiming_const_ehl = { + .name = KBUILD_MODNAME, + .tseg1_min = 2, /* Time segment 1 = prop_seg + phase_seg1 */ + .tseg1_max = 64, + .tseg2_min = 1, /* Time segment 2 = phase_seg2 */ + .tseg2_max = 128, + .sjw_max = 128, + .brp_min = 1, + .brp_max = 512, + .brp_inc = 1, +}; + +static const struct can_bittiming_const m_can_data_bittiming_const_ehl = { + .name = KBUILD_MODNAME, + .tseg1_min = 2, /* Time segment 1 = prop_seg + phase_seg1 */ + .tseg1_max = 16, + .tseg2_min = 1, /* Time segment 2 = phase_seg2 */ + .tseg2_max = 8, + .sjw_max = 4, + .brp_min = 1, + .brp_max = 32, + .brp_inc = 1, +}; + +static const struct m_can_pci_config m_can_pci_ehl = { + .bit_timing = &m_can_bittiming_const_ehl, + .data_timing = &m_can_data_bittiming_const_ehl, + .clock_freq = 200000000, +}; + static int m_can_pci_probe(struct pci_dev *pci, const struct pci_device_id *id) { struct device *dev = &pci->dev; + const struct m_can_pci_config *cfg; struct m_can_classdev *mcan_class; struct m_can_pci_priv *priv; void __iomem *base; @@ -114,6 +150,8 @@ static int m_can_pci_probe(struct pci_dev *pci, const struct pci_device_id *id) if (!mcan_class) return -ENOMEM;
+ cfg = (const struct m_can_pci_config *)id->driver_data; + priv = cdev_to_priv(mcan_class);
priv->base = base; @@ -125,7 +163,9 @@ static int m_can_pci_probe(struct pci_dev *pci, const struct pci_device_id *id) mcan_class->dev = &pci->dev; mcan_class->net->irq = pci_irq_vector(pci, 0); mcan_class->pm_clock_support = 1; - mcan_class->can.clock.freq = id->driver_data; + mcan_class->bit_timing = cfg->bit_timing; + mcan_class->data_timing = cfg->data_timing; + mcan_class->can.clock.freq = cfg->clock_freq; mcan_class->ops = &m_can_pci_ops;
pci_set_drvdata(pci, mcan_class); @@ -178,8 +218,8 @@ static SIMPLE_DEV_PM_OPS(m_can_pci_pm_ops, m_can_pci_suspend, m_can_pci_resume);
static const struct pci_device_id m_can_pci_id_table[] = { - { PCI_VDEVICE(INTEL, 0x4bc1), M_CAN_CLOCK_FREQ_EHL, }, - { PCI_VDEVICE(INTEL, 0x4bc2), M_CAN_CLOCK_FREQ_EHL, }, + { PCI_VDEVICE(INTEL, 0x4bc1), (kernel_ulong_t)&m_can_pci_ehl, }, + { PCI_VDEVICE(INTEL, 0x4bc2), (kernel_ulong_t)&m_can_pci_ehl, }, { } /* Terminating Entry */ }; MODULE_DEVICE_TABLE(pci, m_can_pci_id_table);