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Message-ID: <20210518134332.17826-3-patrice.chotard@foss.st.com>
Date: Tue, 18 May 2021 15:43:31 +0200
From: <patrice.chotard@...s.st.com>
To: Mark Brown <broonie@...nel.org>,
Miquel Raynal <miquel.raynal@...tlin.com>,
Vignesh Raghavendra <vigneshr@...com>,
Boris Brezillon <boris.brezillon@...labora.com>,
<linux-mtd@...ts.infradead.org>,
Alexandre Torgue <alexandre.torgue@...s.st.com>,
<linux-spi@...r.kernel.org>,
<linux-stm32@...md-mailman.stormreply.com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>
CC: <patrice.chotard@...s.st.com>, <christophe.kerello@...s.st.com>
Subject: [PATCH v4 2/3] mtd: spinand: use the spi-mem poll status APIs
From: Patrice Chotard <patrice.chotard@...s.st.com>
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@...s.st.com>
Signed-off-by: Christophe Kerello <christophe.kerello@...s.st.com>
---
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
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