Re: mmc: dw_mmc: miscaculated the fifo-depth with wrong bit operation

[James Hogan <james.hogan@imgtec.com>]

On 09/01/12 09:41, James Hogan wrote:
> On 01/09/2012 01:06 AM, Jaehoon Chung wrote:
>> In FIFOTH register, can find "bit[27:16] = FIFO_DEPTH - 1".
>> Finally, FIFO_DEPTH = bit[27:16] + 1.
>>
>> Now, Used the 0x7ff. but 0xfff is right.
> 
> Nice catch. The patch itself looks okay, but I don't think the commit
> message is very understandable, maybe something like this would be better?:
> 
> In FIFOTH register, the RX_WMark field (bits[27:16]) defaults to
> FIFO_DEPTH - 1. When reading it, bits[26:16] were being used, so fix it
> to use the mask 0xfff instead of 0x7ff.
> 
> Cheers
> James

Are you happy having your signed-off-by against this identical patch with
a modified message Jaehoon?

From: Jaehoon Chung <jh80.chung@samsung.com>

In FIFOTH register, the RX_WMark field (bits[27:16]) defaults to
FIFO_DEPTH - 1. When reading it, bits[26:16] were being used, so fix it
to use the mask 0xfff instead of 0x7ff.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
---
 drivers/mmc/host/dw_mmc.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index cc54808..6ea6185 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -2075,7 +2075,7 @@ static int dw_mci_probe(struct platform_device *pdev)
 		 * should put it in the platform data.
 		 */
 		fifo_size = mci_readl(host, FIFOTH);
-		fifo_size = 1 + ((fifo_size >> 16) & 0x7ff);
+		fifo_size = 1 + ((fifo_size >> 16) & 0xfff);
 	} else {
 		fifo_size = host->pdata->fifo_depth;
 	}
-- 
1.7.2.3