From ebf45b7d029eb065819bfede8b30455630d76c68 Mon Sep 17 00:00:00 2001 From: Feng Tang Date: Fri, 24 Dec 2010 13:59:09 +0800 Subject: [PATCH] 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: Arjan van de Ven Signed-off-by: Alan Cox Signed-off-by: Feng Tang Signed-off-by: Grant Likely --- drivers/spi/dw_spi.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/spi/dw_spi.c b/drivers/spi/dw_spi.c index 0838c79..25238a8 100644 --- a/drivers/spi/dw_spi.c +++ b/drivers/spi/dw_spi.c @@ -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); } -- 2.7.4