On Tue, 18 May 2021 15:43:31 +0200 <patrice.chotard@xxxxxxxxxxx> wrote: > From: Patrice Chotard <patrice.chotard@xxxxxxxxxxx> > > Make use of spi-mem poll status APIs to let advanced controllers > optimize wait operations. > This should also fix the high CPU usage for system that don't have > a dedicated STATUS poll block logic. > > Signed-off-by: Patrice Chotard <patrice.chotard@xxxxxxxxxxx> > Signed-off-by: Christophe Kerello <christophe.kerello@xxxxxxxxxxx> Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> > --- > Changes in v4: > - Update commit message. > - Add comment which explains how delays has been calculated. > - Rename SPINAND_STATUS_TIMEOUT_MS to SPINAND_WAITRDY_TIMEOUT_MS. > > Changes in v3: > - Add initial_delay_us and polling_delay_us parameters to spinand_wait() > - Add SPINAND_READ/WRITE/ERASE/RESET_INITIAL_DELAY_US and > SPINAND_READ/WRITE/ERASE/RESET_POLL_DELAY_US defines. > > Changes in v2: > - non-offload case is now managed by spi_mem_poll_status() > > drivers/mtd/nand/spi/core.c | 45 ++++++++++++++++++++++++++----------- > include/linux/mtd/spinand.h | 22 ++++++++++++++++++ > 2 files changed, 54 insertions(+), 13 deletions(-) > > diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c > index 17f63f95f4a2..3131fae0c715 100644 > --- a/drivers/mtd/nand/spi/core.c > +++ b/drivers/mtd/nand/spi/core.c > @@ -473,20 +473,26 @@ static int spinand_erase_op(struct spinand_device *spinand, > return spi_mem_exec_op(spinand->spimem, &op); > } > > -static int spinand_wait(struct spinand_device *spinand, u8 *s) > +static int spinand_wait(struct spinand_device *spinand, > + unsigned long initial_delay_us, > + unsigned long poll_delay_us, > + u8 *s) > { > - unsigned long timeo = jiffies + msecs_to_jiffies(400); > + struct spi_mem_op op = SPINAND_GET_FEATURE_OP(REG_STATUS, > + spinand->scratchbuf); > u8 status; > int ret; > > - do { > - ret = spinand_read_status(spinand, &status); > - if (ret) > - return ret; > + ret = spi_mem_poll_status(spinand->spimem, &op, STATUS_BUSY, 0, > + initial_delay_us, > + poll_delay_us, > + SPINAND_WAITRDY_TIMEOUT_MS); > + if (ret) > + return ret; > > - if (!(status & STATUS_BUSY)) > - goto out; > - } while (time_before(jiffies, timeo)); > + status = *spinand->scratchbuf; > + if (!(status & STATUS_BUSY)) > + goto out; > > /* > * Extra read, just in case the STATUS_READY bit has changed > @@ -526,7 +532,10 @@ static int spinand_reset_op(struct spinand_device *spinand) > if (ret) > return ret; > > - return spinand_wait(spinand, NULL); > + return spinand_wait(spinand, > + SPINAND_RESET_INITIAL_DELAY_US, > + SPINAND_RESET_POLL_DELAY_US, > + NULL); > } > > static int spinand_lock_block(struct spinand_device *spinand, u8 lock) > @@ -549,7 +558,10 @@ static int spinand_read_page(struct spinand_device *spinand, > if (ret) > return ret; > > - ret = spinand_wait(spinand, &status); > + ret = spinand_wait(spinand, > + SPINAND_READ_INITIAL_DELAY_US, > + SPINAND_READ_POLL_DELAY_US, > + &status); > if (ret < 0) > return ret; > > @@ -585,7 +597,10 @@ static int spinand_write_page(struct spinand_device *spinand, > if (ret) > return ret; > > - ret = spinand_wait(spinand, &status); > + ret = spinand_wait(spinand, > + SPINAND_WRITE_INITIAL_DELAY_US, > + SPINAND_WRITE_POLL_DELAY_US, > + &status); > if (!ret && (status & STATUS_PROG_FAILED)) > return -EIO; > > @@ -768,7 +783,11 @@ static int spinand_erase(struct nand_device *nand, const struct nand_pos *pos) > if (ret) > return ret; > > - ret = spinand_wait(spinand, &status); > + ret = spinand_wait(spinand, > + SPINAND_ERASE_INITIAL_DELAY_US, > + SPINAND_ERASE_POLL_DELAY_US, > + &status); > + > if (!ret && (status & STATUS_ERASE_FAILED)) > ret = -EIO; > > diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h > index 6bb92f26833e..6988956b8492 100644 > --- a/include/linux/mtd/spinand.h > +++ b/include/linux/mtd/spinand.h > @@ -170,6 +170,28 @@ struct spinand_op; > struct spinand_device; > > #define SPINAND_MAX_ID_LEN 4 > +/* > + * For erase, write and read operation, we got the following timings : > + * tBERS (erase) 1ms to 4ms > + * tPROG 300us to 400us > + * tREAD 25us to 100us > + * In order to minimize latency, the min value is divided by 4 for the > + * initial delay, and dividing by 20 for the poll delay. > + * For reset, 5us/10us/500us if the device is respectively > + * reading/programming/erasing when the RESET occurs. Since we always > + * issue a RESET when the device is IDLE, 5us is selected for both initial > + * and poll delay. > + */ > +#define SPINAND_READ_INITIAL_DELAY_US 6 > +#define SPINAND_READ_POLL_DELAY_US 5 > +#define SPINAND_RESET_INITIAL_DELAY_US 5 > +#define SPINAND_RESET_POLL_DELAY_US 5 > +#define SPINAND_WRITE_INITIAL_DELAY_US 75 > +#define SPINAND_WRITE_POLL_DELAY_US 15 > +#define SPINAND_ERASE_INITIAL_DELAY_US 250 > +#define SPINAND_ERASE_POLL_DELAY_US 50 > + > +#define SPINAND_WAITRDY_TIMEOUT_MS 400 > > /** > * struct spinand_id - SPI NAND id structure