Re: [PATCH 1/3] mtd: spi-nor: Use the spi-mem poll status APIs.

Sergey Shtylyov
2022-07-23T08:31:30Z

Hello!

On 7/22/22 7:48 PM, 周琰杰 (Zhou Yanjie) wrote:

> With advanced controllers (such as Ingenic SFC), it is possible to poll
> the status register of the device. This could be done to offload the CPU
> during a erase or write operation. Make use of spi-mem poll status APIs
> to handle this feature.
>
> Previously, when erasing large area (e.g. 32MiB), in non-offload case,
> CPU load could reach ~90% and would generate ~3.92 million interrupts,
> now it decrease to ~15% CPU load and 0.15 million interrupts.
>
> This should also fix the high CPU usage for system which don't have a
> dedicated poll status block logic (decrease to ~80% CPU load and ~1.61
> million interrupts.).
>
> Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
> ---
> drivers/mtd/spi-nor/core.c | 42 ++++++++++++++++++++++++++++++++----------
> 1 file changed, 32 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index 502967c..6a31132 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -617,19 +617,41 @@ static int spi_nor_wait_till_ready_with_timeout(struct spi_nor *nor,
> unsigned long deadline;
> int timeout = 0, ret;
>
> - deadline = jiffies + timeout_jiffies;
> + if (nor->spimem && !nor->params->ready) {
> + struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDSR, 0),
> + SPI_MEM_OP_NO_ADDR,
> + SPI_MEM_OP_NO_DUMMY,
> + SPI_MEM_OP_DATA_IN(1, nor->bouncebuf, 0));

Strange indentation...

[...]
> + return spi_mem_poll_status(nor->spimem, &op, SR_WIP, 0, 0, 10,
> + jiffies_to_msecs(timeout_jiffies));

Here as well...

[...]

MBR, Sergey