[PATCH net] can: m_can: pci: fix iomap_read_fifo() and iomap_write_fifo()

[PATCH net] can: m_can: pci: fix iomap_read_fifo() and iomap_write_fifo()

[Matthias Schiffer]

The same fix that was previously done in m_can_platform in commit
99d173fbe894 ("can: m_can: fix iomap_read_fifo() and iomap_write_fifo()")
is required in m_can_pci as well to make iomap_read_fifo() and
iomap_write_fifo() work for val_count > 1.

Fixes: 812270e5445b ("can: m_can: Batch FIFO writes during CAN transmit")
Fixes: 1aa6772f64b4 ("can: m_can: Batch FIFO reads during CAN receive")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---
 drivers/net/can/m_can/m_can_pci.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/m_can/m_can_pci.c b/drivers/net/can/m_can/m_can_pci.c
index 8bbbaa264f0d..b56a54d6c5a9 100644
--- a/drivers/net/can/m_can/m_can_pci.c
+++ b/drivers/net/can/m_can/m_can_pci.c
@@ -47,8 +47,13 @@ static u32 iomap_read_reg(struct m_can_classdev *cdev, int reg)
 static int iomap_read_fifo(struct m_can_classdev *cdev, int offset, void *val, size_t val_count)
 {
 	struct m_can_pci_priv *priv = cdev_to_priv(cdev);
+	void __iomem *src = priv->base + offset;
 
-	ioread32_rep(priv->base + offset, val, val_count);
+	while (val_count--) {
+		*(unsigned int *)val = ioread32(src);
+		val += 4;
+		src += 4;
+	}
 
 	return 0;
 }
@@ -66,8 +71,13 @@ static int iomap_write_fifo(struct m_can_classdev *cdev, int offset,
 			    const void *val, size_t val_count)
 {
 	struct m_can_pci_priv *priv = cdev_to_priv(cdev);
+	void __iomem *dst = priv->base + offset;
 
-	iowrite32_rep(priv->base + offset, val, val_count);
+	while (val_count--) {
+		iowrite32(*(unsigned int *)val, dst);
+		val += 4;
+		dst += 4;
+	}
 
 	return 0;
 }
-- 
2.17.1

Re: [PATCH net] can: m_can: pci: fix iomap_read_fifo() and iomap_write_fifo()

[Jarkko Nikula]

On 11/18/21 4:40 PM, Matthias Schiffer wrote:
> The same fix that was previously done in m_can_platform in commit
> 99d173fbe894 ("can: m_can: fix iomap_read_fifo() and iomap_write_fifo()")
> is required in m_can_pci as well to make iomap_read_fifo() and
> iomap_write_fifo() work for val_count > 1.
> 
> Fixes: 812270e5445b ("can: m_can: Batch FIFO writes during CAN transmit")
> Fixes: 1aa6772f64b4 ("can: m_can: Batch FIFO reads during CAN receive")
> Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> ---
>   drivers/net/can/m_can/m_can_pci.c | 14 ++++++++++++--
>   1 file changed, 12 insertions(+), 2 deletions(-)
> 
I tested this on top of plain v5.15 (v5.16-rc1 has some rootfs 
regression on my EHL HW) where my test case was receiving zeros and this 
makes it working again like in v5.14 and earlier.

Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>