Messages in this thread Patch in this message | | | From | unsik Kim <> | Subject | [PATCH 2/2] mg_disk: fix reading invalid status when use polling driver | Date | Thu, 23 Jul 2009 13:57:46 +0900 |
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When using polling driver, little delay is required to access status register. Without this, host might read invalid status.
Signed-off-by: unsik Kim <donari75@gmail.com> --- drivers/block/mg_disk.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/drivers/block/mg_disk.c b/drivers/block/mg_disk.c index 26371d5..6d7fbaa 100644 --- a/drivers/block/mg_disk.c +++ b/drivers/block/mg_disk.c @@ -218,6 +218,16 @@ static unsigned int mg_wait(struct mg_host *host, u32 expect, u32 msec) host->error = MG_ERR_NONE; expire = jiffies + msecs_to_jiffies(msec); + /* These 2 times dummy status read prevents reading invalid + * status. A very little time (3 times of mflash operating clk) + * is required for busy bit is set. Use dummy read instead of + * busy wait, because mflash's PLL is machine dependent. + */ + if (prv_data->use_polling) { + status = inb((unsigned long)host->dev_base + MG_REG_STATUS); + status = inb((unsigned long)host->dev_base + MG_REG_STATUS); + } + status = inb((unsigned long)host->dev_base + MG_REG_STATUS); do { -- 1.6.0.6
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