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can: gs_usb: add usb quirk for NXP LPC546xx controllers

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Introduce a workaround for a NXP chip errata on LPC546xx
controllers (Errata sheet LPC546xx / USB.15).

According to the document corruption can occur when the following
conditions are met:
* A TX (IN) transfer happens after a RX (OUT) transfer.
* The RX (OUT) transfer length is 4 + N * 16 (N >= 0) bytes.

Even though the struct gs_host_frame has a size of 76 bytes for a FD
frame, which does not apply to the above rule, corruption could be
seen.

Adding a dummy byte to break the second condition also on transfer
lengths with 4 + N * 8 bytes reliably circumvents USB transfer data
corruption.

The firmware can now request this quirk by setting
GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX.

Link: https://lore.kernel.org/all/20220309124132.291861-17-mkl@pengutronix.de
Signed-off-by: Peter Fink <pfink@christ-es.de>
Signed-off-by: Christoph Möhring <cmoehring@christ-es.de>
Signed-off-by: Alexander Schartner <aschartner@christ-es.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Peter Fink
2021-12-07 19:43:24 +01:00
committed by Marc Kleine-Budde
parent 26949ac935
commit eb9fa77a42
1 changed files with 27 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/net/can/usb/gs_usb.c
+27 -2
View File
@@ -9,6 +9,7 @@
* Many thanks to all socketcan devs!
*/
#include <linux/bitfield.h>
#include <linux/ethtool.h>
#include <linux/init.h>
#include <linux/module.h>
@@ -100,6 +101,7 @@ struct gs_device_config {
/* GS_CAN_FEATURE_USER_ID BIT(6) */
#define GS_CAN_MODE_PAD_PKTS_TO_MAX_PKT_SIZE BIT(7)
#define GS_CAN_MODE_FD BIT(8)
/* GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX BIT(9) */
struct gs_device_mode {
__le32 mode;
@@ -133,6 +135,8 @@ struct gs_identify_mode {
#define GS_CAN_FEATURE_USER_ID BIT(6)
#define GS_CAN_FEATURE_PAD_PKTS_TO_MAX_PKT_SIZE BIT(7)
#define GS_CAN_FEATURE_FD BIT(8)
#define GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX BIT(9)
#define GS_CAN_FEATURE_MASK GENMASK(9, 0)
struct gs_device_bt_const {
__le32 feature;
@@ -156,10 +160,20 @@ struct classic_can {
u8 data[8];
} __packed;
struct classic_can_quirk {
u8 data[8];
u8 quirk;
} __packed;
struct canfd {
u8 data[64];
} __packed;
struct canfd_quirk {
u8 data[64];
u8 quirk;
} __packed;
struct gs_host_frame {
u32 echo_id;
__le32 can_id;
@@ -171,7 +185,9 @@ struct gs_host_frame {
union {
DECLARE_FLEX_ARRAY(struct classic_can, classic_can);
DECLARE_FLEX_ARRAY(struct classic_can_quirk, classic_can_quirk);
DECLARE_FLEX_ARRAY(struct canfd, canfd);
DECLARE_FLEX_ARRAY(struct canfd_quirk, canfd_quirk);
};
} __packed;
/* The GS USB devices make use of the same flags and masks as in
@@ -204,6 +220,7 @@ struct gs_can {
struct can_bittiming_const bt_const;
unsigned int channel; /* channel number */
u32 feature;
unsigned int hf_size_tx;
/* This lock prevents a race condition between xmit and receive. */
@@ -666,9 +683,16 @@ static int gs_can_open(struct net_device *netdev)
ctrlmode = dev->can.ctrlmode;
if (ctrlmode & CAN_CTRLMODE_FD) {
flags |= GS_CAN_MODE_FD;
dev->hf_size_tx = struct_size(hf, canfd, 1);
if (dev->feature & GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX)
dev->hf_size_tx = struct_size(hf, canfd_quirk, 1);
else
dev->hf_size_tx = struct_size(hf, canfd, 1);
} else {
dev->hf_size_tx = struct_size(hf, classic_can, 1);
if (dev->feature & GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX)
dev->hf_size_tx = struct_size(hf, classic_can_quirk, 1);
else
dev->hf_size_tx = struct_size(hf, classic_can, 1);
}
if (!parent->active_channels) {
@@ -938,6 +962,7 @@ static struct gs_can *gs_make_candev(unsigned int channel,
dev->can.ctrlmode_supported = CAN_CTRLMODE_CC_LEN8_DLC;
feature = le32_to_cpu(bt_const->feature);
dev->feature = FIELD_GET(GS_CAN_FEATURE_MASK, feature);
if (feature & GS_CAN_FEATURE_LISTEN_ONLY)
dev->can.ctrlmode_supported |= CAN_CTRLMODE_LISTENONLY;