[PATCH v1] spi: spi-mtk-nor: Optimize timeout for dma read

From: Bayi Cheng
Date: Thu Nov 03 2022 - 01:29:31 EST


From: bayi cheng <bayi.cheng@xxxxxxxxxxxx>

The timeout value of the current dma read is unreasonable. For example,
If the spi flash clock is 26Mhz, It will takes about 1.3ms to read a
4KB data in spi mode. But the actual measurement exceeds 50s when a
dma read timeout is encountered.

In order to be more accurately, It is necessary to use msecs_to_jiffies,
After modification, the measured timeout value is about 130ms.

Signed-off-by: bayi cheng <bayi.cheng@xxxxxxxxxxxx>
---
drivers/spi/spi-mtk-nor.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-mtk-nor.c b/drivers/spi/spi-mtk-nor.c
index d167699a1a96..3d989db80ee9 100644
--- a/drivers/spi/spi-mtk-nor.c
+++ b/drivers/spi/spi-mtk-nor.c
@@ -354,7 +354,7 @@ static int mtk_nor_dma_exec(struct mtk_nor *sp, u32 from, unsigned int length,
dma_addr_t dma_addr)
{
int ret = 0;
- ulong delay;
+ ulong delay, timeout;
u32 reg;

writel(from, sp->base + MTK_NOR_REG_DMA_FADR);
@@ -376,15 +376,16 @@ static int mtk_nor_dma_exec(struct mtk_nor *sp, u32 from, unsigned int length,
mtk_nor_rmw(sp, MTK_NOR_REG_DMA_CTL, MTK_NOR_DMA_START, 0);

delay = CLK_TO_US(sp, (length + 5) * BITS_PER_BYTE);
+ timeout = (delay + 1) * 100;

if (sp->has_irq) {
if (!wait_for_completion_timeout(&sp->op_done,
- (delay + 1) * 100))
+ msecs_to_jiffies(max_t(size_t, timeout / 1000, 10))))
ret = -ETIMEDOUT;
} else {
ret = readl_poll_timeout(sp->base + MTK_NOR_REG_DMA_CTL, reg,
!(reg & MTK_NOR_DMA_START), delay / 3,
- (delay + 1) * 100);
+ timeout);
}

if (ret < 0)
--
2.25.1