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> --- 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 -- 2.17.1