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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: unsik Kim <donari75@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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@ -219,6 +219,16 @@ static unsigned int mg_wait(struct mg_host *host, u32 expect, u32 msec)
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host->error = MG_ERR_NONE;
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expire = jiffies + msecs_to_jiffies(msec);
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/* These 2 times dummy status read prevents reading invalid
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* status. A very little time (3 times of mflash operating clk)
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* is required for busy bit is set. Use dummy read instead of
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* busy wait, because mflash's PLL is machine dependent.
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*/
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if (prv_data->use_polling) {
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status = inb((unsigned long)host->dev_base + MG_REG_STATUS);
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status = inb((unsigned long)host->dev_base + MG_REG_STATUS);
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}
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status = inb((unsigned long)host->dev_base + MG_REG_STATUS);
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do {
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