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Commit ebf45b7d authored by Feng Tang's avatar Feng Tang Committed by Grant Likely
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spi/dw_spi: Fix too short timeout in spi polling loop 



The SPI polling loop timeout only works with HZ=100 as the loop was
actually too short.

Also add appropriate cpu_relax() in the busy wait loops...

Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarFeng Tang <feng.tang@intel.com>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent 5e8b821d

drivers/spi/dw_spi.c

+6 −3
Original line number Diff line number Diff line
@@ -164,20 +164,23 @@ static inline void mrst_spi_debugfs_remove(struct dw_spi *dws) 


static void wait_till_not_busy(struct dw_spi *dws)

{

	unsigned long end = jiffies + 1 + usecs_to_jiffies(1000);

	unsigned long end = jiffies + 1 + usecs_to_jiffies(5000);



	while (time_before(jiffies, end)) {

		if (!(dw_readw(dws, sr) & SR_BUSY))

			return;

		cpu_relax();

	}

	dev_err(&dws->master->dev,

		"DW SPI: Status keeps busy for 1000us after a read/write!\n");

		"DW SPI: Status keeps busy for 5000us after a read/write!\n");

}



static void flush(struct dw_spi *dws)

{

	while (dw_readw(dws, sr) & SR_RF_NOT_EMPT)

	while (dw_readw(dws, sr) & SR_RF_NOT_EMPT) {

		dw_readw(dws, dr);

		cpu_relax();

	}



	wait_till_not_busy(dws);

}