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Commit eb32baec authored by unsik Kim's avatar unsik Kim Committed by Jens Axboe
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mg_disk: fix reading invalid status when use polling driver 



When using polling driver, little delay is required to access
status register. Without this, host might read invalid status.

Signed-off-by: default avatarunsik Kim <donari75@gmail.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 48f5690d

drivers/block/mg_disk.c

+10 −0
Original line number Diff line number Diff line
@@ -219,6 +219,16 @@ 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 {