2019-07-24 08:35:38

by Rayagonda Kokatanur

[permalink] [raw]
Subject: [PATCH v1 1/1] i2c: iproc: Fix i2c master read more than 63 bytes

Use SMBUS_MASTER_DATA_READ.MASTER_RD_STATUS bit to check for RX
FIFO empty condition because SMBUS_MASTER_FIFO_CONTROL.MASTER_RX_PKT_COUNT
is not updated for read >= 64 bytes. This fixes the issue when trying to
read from the I2C slave more than 63 bytes.

Fixes: c24b8d574b7c ("i2c: iproc: Extend I2C read up to 255 bytes")

Signed-off-by: Rayagonda Kokatanur <[email protected]>
---
drivers/i2c/busses/i2c-bcm-iproc.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c
index 2c7f145..d7fd76b 100644
--- a/drivers/i2c/busses/i2c-bcm-iproc.c
+++ b/drivers/i2c/busses/i2c-bcm-iproc.c
@@ -392,16 +392,18 @@ static bool bcm_iproc_i2c_slave_isr(struct bcm_iproc_i2c_dev *iproc_i2c,
static void bcm_iproc_i2c_read_valid_bytes(struct bcm_iproc_i2c_dev *iproc_i2c)
{
struct i2c_msg *msg = iproc_i2c->msg;
+ uint32_t val;

/* Read valid data from RX FIFO */
while (iproc_i2c->rx_bytes < msg->len) {
- if (!((iproc_i2c_rd_reg(iproc_i2c, M_FIFO_CTRL_OFFSET) >> M_FIFO_RX_CNT_SHIFT)
- & M_FIFO_RX_CNT_MASK))
+ val = iproc_i2c_rd_reg(iproc_i2c, M_RX_OFFSET);
+
+ /* rx fifo empty */
+ if (!((val >> M_RX_STATUS_SHIFT) & M_RX_STATUS_MASK))
break;

msg->buf[iproc_i2c->rx_bytes] =
- (iproc_i2c_rd_reg(iproc_i2c, M_RX_OFFSET) >>
- M_RX_DATA_SHIFT) & M_RX_DATA_MASK;
+ (val >> M_RX_DATA_SHIFT) & M_RX_DATA_MASK;
iproc_i2c->rx_bytes++;
}
}
--
1.9.1


2019-07-30 23:30:38

by Ray Jui

[permalink] [raw]
Subject: Re: [PATCH v1 1/1] i2c: iproc: Fix i2c master read more than 63 bytes

Hi Rayagonda,

On 7/24/2019 1:28 AM, Rayagonda Kokatanur wrote:
> Use SMBUS_MASTER_DATA_READ.MASTER_RD_STATUS bit to check for RX
> FIFO empty condition because SMBUS_MASTER_FIFO_CONTROL.MASTER_RX_PKT_COUNT
> is not updated for read >= 64 bytes. This fixes the issue when trying to
> read from the I2C slave more than 63 bytes.
>
> Fixes: c24b8d574b7c ("i2c: iproc: Extend I2C read up to 255 bytes")
>
> Signed-off-by: Rayagonda Kokatanur <[email protected]>
> ---
> drivers/i2c/busses/i2c-bcm-iproc.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c
> index 2c7f145..d7fd76b 100644
> --- a/drivers/i2c/busses/i2c-bcm-iproc.c
> +++ b/drivers/i2c/busses/i2c-bcm-iproc.c
> @@ -392,16 +392,18 @@ static bool bcm_iproc_i2c_slave_isr(struct bcm_iproc_i2c_dev *iproc_i2c,
> static void bcm_iproc_i2c_read_valid_bytes(struct bcm_iproc_i2c_dev *iproc_i2c)
> {
> struct i2c_msg *msg = iproc_i2c->msg;
> + uint32_t val;
>
> /* Read valid data from RX FIFO */
> while (iproc_i2c->rx_bytes < msg->len) {
> - if (!((iproc_i2c_rd_reg(iproc_i2c, M_FIFO_CTRL_OFFSET) >> M_FIFO_RX_CNT_SHIFT)
> - & M_FIFO_RX_CNT_MASK))
> + val = iproc_i2c_rd_reg(iproc_i2c, M_RX_OFFSET);
> +
> + /* rx fifo empty */
> + if (!((val >> M_RX_STATUS_SHIFT) & M_RX_STATUS_MASK))
> break;
>
> msg->buf[iproc_i2c->rx_bytes] =
> - (iproc_i2c_rd_reg(iproc_i2c, M_RX_OFFSET) >>
> - M_RX_DATA_SHIFT) & M_RX_DATA_MASK;
> + (val >> M_RX_DATA_SHIFT) & M_RX_DATA_MASK;
> iproc_i2c->rx_bytes++;
> }
> }
>

Thanks for the fix. This fix looks good to me!

Reviewed-by: Ray Jui <[email protected]>

2019-08-01 12:33:53

by Wolfram Sang

[permalink] [raw]
Subject: Re: [PATCH v1 1/1] i2c: iproc: Fix i2c master read more than 63 bytes

On Wed, Jul 24, 2019 at 01:58:27PM +0530, Rayagonda Kokatanur wrote:
> Use SMBUS_MASTER_DATA_READ.MASTER_RD_STATUS bit to check for RX
> FIFO empty condition because SMBUS_MASTER_FIFO_CONTROL.MASTER_RX_PKT_COUNT
> is not updated for read >= 64 bytes. This fixes the issue when trying to
> read from the I2C slave more than 63 bytes.
>
> Fixes: c24b8d574b7c ("i2c: iproc: Extend I2C read up to 255 bytes")
>
> Signed-off-by: Rayagonda Kokatanur <[email protected]>

Applied to for-current, thanks!

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