spi/dw_spi: Fix too short timeout in spi polling loop

[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / spi / dw_spi.c

diff --git a/drivers/spi/dw_spi.c b/drivers/spi/dw_spi.c
index 9043931..25238a8 100644 (file)
--- 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);
 }
@@ -413,6 +416,11 @@ static void poll_transfer(struct dw_spi *dws)
 {
        while (dws->write(dws))
                dws->read(dws);
+       /*
+        * There is a possibility that the last word of a transaction
+        * will be lost if data is not ready. Re-read to solve this issue.
+        */
+       dws->read(dws);
 
        transfer_complete(dws);
 }