[PATCH 0/3] mtd: spi-nor: stm32-quadspi: fixes

[PATCH 0/3] mtd: spi-nor: stm32-quadspi: fixes

[Ludovic Barre]

From: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>

This series adds:
-Fix: to avoid compilation warning with older compiler
versions such as gcc-4.6.
This topic has been discussed on 2 threads with Geert and Arnd
https://lkml.org/lkml/2017/9/15/70
https://www.spinics.net/lists/arm-kernel/msg606269.html
-Fix: abort prefetching in memory-mapped mode as soon prefetching
could exceed nor size (not done by fsize limit)
-Change license text and Copyright

Geert Uytterhoeven (1):
  mtd: spi-nor: stm32-quadspi: Fix uninitialized error return code

Ludovic Barre (2):
  mtd: spi-nor: stm32-quadspi: fix prefetching outside fsize
  mtd: spi-nor: stm32-quadspi: change license text

 drivers/mtd/spi-nor/stm32-quadspi.c | 35 +++++++++++++++++++++++++++++------
 1 file changed, 29 insertions(+), 6 deletions(-)

-- 
2.7.4

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[PATCH 1/3] mtd: spi-nor: stm32-quadspi: Fix uninitialized error return code

[Ludovic Barre]

From: Geert Uytterhoeven <geert@linux-m68k.org>

With gcc 4.1.2:

    drivers/mtd/spi-nor/stm32-quadspi.c: In function ‘stm32_qspi_tx_poll’:
    drivers/mtd/spi-nor/stm32-quadspi.c:230: warning: ‘ret’ may be used uninitialized in this function

Indeed, if stm32_qspi_cmd.len is zero, ret will be uninitialized.
This length is passed from outside the driver using the
spi_nor.{read,write}{,_reg}() callbacks.

Several functions in drivers/mtd/spi-nor/spi-nor.c (e.g. write_enable(),
write_disable(), and erase_chip()) call spi_nor.write_reg() with a zero
length.

Fix this by returning an explicit zero on success.

Fixes: 0d43d7ab277a048c ("mtd: spi-nor: add driver for STM32 quad spi flash controller")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
---
 drivers/mtd/spi-nor/stm32-quadspi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
index 86c0931..ad6a3e1 100644
--- a/drivers/mtd/spi-nor/stm32-quadspi.c
+++ b/drivers/mtd/spi-nor/stm32-quadspi.c
@@ -240,12 +240,12 @@ static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
 						 STM32_QSPI_FIFO_TIMEOUT_US);
 		if (ret) {
 			dev_err(qspi->dev, "fifo timeout (stat:%#x)\n", sr);
-			break;
+			return ret;
 		}
 		tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
 	}
 
-	return ret;
+	return 0;
 }
 
 static int stm32_qspi_tx_mm(struct stm32_qspi *qspi,
-- 
2.7.4

[PATCH 2/3] mtd: spi-nor: stm32-quadspi: fix prefetching outside fsize

[Ludovic Barre]

From: Ludovic Barre <ludovic.barre@st.com>

When memory-mapped mode is used, a prefetching mechanism fully
managed by the hardware allows to optimize the read from external
the QSPI memory. A 32-bytes FIFO is used for prefetching.
When the limit of flash size - fifo size is reached the prefetching
mechanism tries to read outside the fsize.
The stm32 quadspi hardware become busy and should be aborted.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Reported-by: Bruno Herrera <bruherrera@gmail.com>
Tested-by: Bruno Herrera <bruherrera@gmail.com>
---
 drivers/mtd/spi-nor/stm32-quadspi.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
index ad6a3e1..70710be 100644
--- a/drivers/mtd/spi-nor/stm32-quadspi.c
+++ b/drivers/mtd/spi-nor/stm32-quadspi.c
@@ -113,6 +113,7 @@
 #define STM32_MAX_MMAP_SZ	SZ_256M
 #define STM32_MAX_NORCHIP	2
 
+#define STM32_QSPI_FIFO_SZ	32
 #define STM32_QSPI_FIFO_TIMEOUT_US 30000
 #define STM32_QSPI_BUSY_TIMEOUT_US 100000
 
@@ -124,6 +125,7 @@ struct stm32_qspi_flash {
 	u32 presc;
 	u32 read_mode;
 	bool registered;
+	u32 prefetch_limit;
 };
 
 struct stm32_qspi {
@@ -272,6 +274,7 @@ static int stm32_qspi_send(struct stm32_qspi_flash *flash,
 {
 	struct stm32_qspi *qspi = flash->qspi;
 	u32 ccr, dcr, cr;
+	u32 last_byte;
 	int err;
 
 	err = stm32_qspi_wait_nobusy(qspi);
@@ -314,6 +317,10 @@ static int stm32_qspi_send(struct stm32_qspi_flash *flash,
 		if (err)
 			goto abort;
 		writel_relaxed(FCR_CTCF, qspi->io_base + QUADSPI_FCR);
+	} else {
+		last_byte = cmd->addr + cmd->len;
+		if (last_byte > flash->prefetch_limit)
+			goto abort;
 	}
 
 	return err;
@@ -322,7 +329,9 @@ static int stm32_qspi_send(struct stm32_qspi_flash *flash,
 	cr = readl_relaxed(qspi->io_base + QUADSPI_CR) | CR_ABORT;
 	writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
 
-	dev_err(qspi->dev, "%s abort err:%d\n", __func__, err);
+	if (err)
+		dev_err(qspi->dev, "%s abort err:%d\n", __func__, err);
+
 	return err;
 }
 
@@ -550,6 +559,7 @@ static int stm32_qspi_flash_setup(struct stm32_qspi *qspi,
 	}
 
 	flash->fsize = FSIZE_VAL(mtd->size);
+	flash->prefetch_limit = mtd->size - STM32_QSPI_FIFO_SZ;
 
 	flash->read_mode = CCR_FMODE_MM;
 	if (mtd->size > qspi->mm_size)
-- 
2.7.4

[PATCH 3/3] mtd: spi-nor: stm32-quadspi: change license text

[Ludovic Barre]

From: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>

-Change the license text with long template.
-Change Copyright to STMicroelectronics.

Signed-off-by: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
---
 drivers/mtd/spi-nor/stm32-quadspi.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
index 70710be..b3c7f6a 100644
--- a/drivers/mtd/spi-nor/stm32-quadspi.c
+++ b/drivers/mtd/spi-nor/stm32-quadspi.c
@@ -1,9 +1,22 @@
 /*
- * stm32_quadspi.c
+ * Driver for stm32 quadspi controller
  *
- * Copyright (C) 2017, Ludovic Barre
+ * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
+ * Author(s): Ludovic Barre author <ludovic.barre-qxv4g6HH51o@public.gmane.org>.
  *
- * License terms: GNU General Public License (GPL), version 2
+ * License terms: GPL V2.0.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * This program. If not, see <http://www.gnu.org/licenses/>.
  */
 #include <linux/clk.h>
 #include <linux/errno.h>
-- 
2.7.4

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