2021-09-20 21:05:54

by Aswath Govindraju

[permalink] [raw]
Subject: [PATCH] can: m_can: m_can_platform: Fix iomap_read_fifo() and iomap_write_fifo()

The read and writes from the fifo are from a buffer, with various fields
and data at predefined offsets. So, they should not be done to the same
address(or port) in case of val_count greater than 1. Therefore, fix this
by using iowrite32/ioread32 instead of ioread32_rep/iowrite32_rep.

Also, the write into fifo must be performed with an offset from the message
ram base address. Therefore, fix the base address to mram_base.

Fixes: e39381770ec9 ("can: m_can: Disable IRQs on FIFO bus errors")
Signed-off-by: Aswath Govindraju <[email protected]>
---
drivers/net/can/m_can/m_can_platform.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/m_can/m_can_platform.c b/drivers/net/can/m_can/m_can_platform.c
index 308d4f2fff00..eee47bad0592 100644
--- a/drivers/net/can/m_can/m_can_platform.c
+++ b/drivers/net/can/m_can/m_can_platform.c
@@ -32,8 +32,13 @@ 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_plat_priv *priv = cdev_to_priv(cdev);
+ void __iomem *src = priv->mram_base + offset;

- ioread32_rep(priv->mram_base + offset, val, val_count);
+ while (val_count--) {
+ *(unsigned int *)val = ioread32(src);
+ val += 4;
+ src += 4;
+ }

return 0;
}
@@ -51,8 +56,13 @@ static int iomap_write_fifo(struct m_can_classdev *cdev, int offset,
const void *val, size_t val_count)
{
struct m_can_plat_priv *priv = cdev_to_priv(cdev);
+ void __iomem *dst = priv->mram_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


2021-10-18 03:47:47

by Marc Kleine-Budde

[permalink] [raw]
Subject: Re: [PATCH] can: m_can: m_can_platform: Fix iomap_read_fifo() and iomap_write_fifo()

On 20.09.2021 18:03:43, Aswath Govindraju wrote:
> The read and writes from the fifo are from a buffer, with various fields
> and data at predefined offsets. So, they should not be done to the same
> address(or port) in case of val_count greater than 1. Therefore, fix this
> by using iowrite32/ioread32 instead of ioread32_rep/iowrite32_rep.
>
> Also, the write into fifo must be performed with an offset from the message
> ram base address. Therefore, fix the base address to mram_base.
>
> Fixes: e39381770ec9 ("can: m_can: Disable IRQs on FIFO bus errors")
> Signed-off-by: Aswath Govindraju <[email protected]>

Applied to linux-can/testing.

Thanks,
Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |


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