[PATCH 0/2] mtd: spi-nor: add stm32 qspi driver

[PATCH 0/2] mtd: spi-nor: add stm32 qspi driver

[Ludovic Barre]

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

This patch set adds a SPI-NOR driver for stm32 QSPI controller.
It is a specialized SPI interface for serial Flash devices.
It supports 1 or 2 Flash device with single, dual and quad SPI Flash memories.

It can operate in any of the following modes:
-indirect mode: all the operations are performed using the quadspi
 registers
-read memory-mapped mode: the external Flash memory is mapped to the
 microcontroller address space and is seen by the system as if it was
 an internal memory

Ludovic Barre (2):
  dt-bindings: Document the STM32 QSPI bindings
  mtd: spi-nor: add driver for STM32 quad spi flash controller

 .../devicetree/bindings/mtd/stm32-quadspi.txt      |  45 ++
 drivers/mtd/spi-nor/Kconfig                        |   7 +
 drivers/mtd/spi-nor/Makefile                       |   1 +
 drivers/mtd/spi-nor/stm32-quadspi.c                | 679 +++++++++++++++++++++
 4 files changed, 732 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mtd/stm32-quadspi.txt
 create mode 100644 drivers/mtd/spi-nor/stm32-quadspi.c

-- 
2.7.4

[PATCH 1/2] dt-bindings: Document the STM32 QSPI bindings

[Ludovic Barre]

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

This patch adds documentation of device tree bindings for the STM32
QSPI controller.

Signed-off-by: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
---
 .../devicetree/bindings/mtd/stm32-quadspi.txt      | 45 ++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mtd/stm32-quadspi.txt

diff --git a/Documentation/devicetree/bindings/mtd/stm32-quadspi.txt b/Documentation/devicetree/bindings/mtd/stm32-quadspi.txt
new file mode 100644
index 0000000..95a8ebd
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/stm32-quadspi.txt
@@ -0,0 +1,45 @@
+* STMicroelectronics Quad Serial Peripheral Interface(QuadSPI)
+
+Required properties:
+- compatible: should be "st,stm32f469-qspi"
+- reg: contains the register location and length.
+  (optional) the memory mapping address and length
+- reg-names: list of the names corresponding to the previous register
+  Should contain "qspi" to register location
+  (optional) "qspi_mm" if read in memory map mode (improve read throughput)
+- interrupts: should contain the interrupt for the device
+- clocks: the phandle of the clock needed by the QSPI controller
+- A pinctrl must be defined to set pins in mode of operation for QSPI transfer
+
+Optional properties:
+- resets: must contain the phandle to the reset controller.
+
+A spi flash must be a child of the nor_flash node and could have some
+properties. Also see jedec,spi-nor.txt.
+
+Required properties:
+- reg: chip-Select number (QSPI controller may connect 2 nor flashes)
+- spi-max-frequency: max frequency of spi bus
+
+Optional property:
+- spi-rx-bus-width: the bus width (number of data wires)
+
+Example:
+
+qspi: qspi@a0001000 {
+	compatible = "st,stm32f469-qspi";
+	reg = <0xa0001000 0x1000>, <0x90000000 0x10000000>;
+	reg-names = "qspi", "qspi_mm";
+	interrupts = <91>;
+	resets = <&rcc STM32F4_AHB3_RESET(QSPI)>;
+	clocks = <&rcc 0 STM32F4_AHB3_CLOCK(QSPI)>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_qspi0>;
+
+	flash@0 {
+		reg = <0>;
+		spi-rx-bus-width = <4>;
+		spi-max-frequency = <108000000>;
+		...
+	};
+};
-- 
2.7.4

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Re: [PATCH 0/2] mtd: spi-nor: add stm32 qspi driver

[Cyrille Pitchen]

Hi Ludovic,

Le 27/03/2017 à 14:54, Ludovic Barre a écrit :
> From: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
> 
> This patch set adds a SPI-NOR driver for stm32 QSPI controller.
> It is a specialized SPI interface for serial Flash devices.
> It supports 1 or 2 Flash device with single, dual and quad SPI Flash memories.
> 
> It can operate in any of the following modes:
> -indirect mode: all the operations are performed using the quadspi
>  registers
> -read memory-mapped mode: the external Flash memory is mapped to the
>  microcontroller address space and is seen by the system as if it was
>  an internal memory
> 
> Ludovic Barre (2):
>   dt-bindings: Document the STM32 QSPI bindings
>   mtd: spi-nor: add driver for STM32 quad spi flash controller
> 
>  .../devicetree/bindings/mtd/stm32-quadspi.txt      |  45 ++
>  drivers/mtd/spi-nor/Kconfig                        |   7 +
>  drivers/mtd/spi-nor/Makefile                       |   1 +
>  drivers/mtd/spi-nor/stm32-quadspi.c                | 679 +++++++++++++++++++++
>  4 files changed, 732 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mtd/stm32-quadspi.txt
>  create mode 100644 drivers/mtd/spi-nor/stm32-quadspi.c
> 

Just a small word to warn you that I'm likely to ask you to rebase this
series onto the patch "mtd: spi-nor: introduce more SPI protocols and
the Dual Transfer Mode". Indeed, I need to synchronize with Marek first
but I plan to merge this patch within few days.


Best regards,

Cyrille
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Re: [PATCH 0/2] mtd: spi-nor: add stm32 qspi driver

[Ludovic BARRE]

hi Cyrille

I see your patch series

[PATCH v5 0/6] mtd: spi-nor: parse SFDP tables to setup (Q)SPI memories

No problem, I rebase my V2 onto your patch


BR
Ludo

On 03/29/2017 06:51 PM, Cyrille Pitchen wrote:
> Hi Ludovic,
>
> Le 27/03/2017 à 14:54, Ludovic Barre a écrit :
>> From: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
>>
>> This patch set adds a SPI-NOR driver for stm32 QSPI controller.
>> It is a specialized SPI interface for serial Flash devices.
>> It supports 1 or 2 Flash device with single, dual and quad SPI Flash memories.
>>
>> It can operate in any of the following modes:
>> -indirect mode: all the operations are performed using the quadspi
>>   registers
>> -read memory-mapped mode: the external Flash memory is mapped to the
>>   microcontroller address space and is seen by the system as if it was
>>   an internal memory
>>
>> Ludovic Barre (2):
>>    dt-bindings: Document the STM32 QSPI bindings
>>    mtd: spi-nor: add driver for STM32 quad spi flash controller
>>
>>   .../devicetree/bindings/mtd/stm32-quadspi.txt      |  45 ++
>>   drivers/mtd/spi-nor/Kconfig                        |   7 +
>>   drivers/mtd/spi-nor/Makefile                       |   1 +
>>   drivers/mtd/spi-nor/stm32-quadspi.c                | 679 +++++++++++++++++++++
>>   4 files changed, 732 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/mtd/stm32-quadspi.txt
>>   create mode 100644 drivers/mtd/spi-nor/stm32-quadspi.c
>>
> Just a small word to warn you that I'm likely to ask you to rebase this
> series onto the patch "mtd: spi-nor: introduce more SPI protocols and
> the Dual Transfer Mode". Indeed, I need to synchronize with Marek first
> but I plan to merge this patch within few days.
>
>
> Best regards,
>
> Cyrille

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Re: [PATCH 0/2] mtd: spi-nor: add stm32 qspi driver

[Marek Vasut]

On 03/30/2017 09:31 AM, Ludovic BARRE wrote:
> hi Cyrille
> 
> I see your patch series
> 
> [PATCH v5 0/6] mtd: spi-nor: parse SFDP tables to setup (Q)SPI memories
> 
> No problem, I rebase my V2 onto your patch

I still didn't review that, so it might take a bit until it hits
mainline. I think the stm32 stuff looks pretty OK, so we can take that
before the SFDP stuff, no?

-- 
Best regards,
Marek Vasut
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Re: [PATCH 0/2] mtd: spi-nor: add stm32 qspi driver

[Ludovic BARRE]

hi Cyrille, Marek

I've re-based and tested my patchset onto

"mtd: spi-nor: introduce more SPI protocols and the Dual Transfer Mode"

So I can deliver my patchset before or after Cyrille patchset

How do you wish process? what version do you want for the v3?


BR

Ludo

On 03/30/2017 12:15 PM, Marek Vasut wrote:
> On 03/30/2017 09:31 AM, Ludovic BARRE wrote:
>> hi Cyrille
>>
>> I see your patch series
>>
>> [PATCH v5 0/6] mtd: spi-nor: parse SFDP tables to setup (Q)SPI memories
>>
>> No problem, I rebase my V2 onto your patch
> I still didn't review that, so it might take a bit until it hits
> mainline. I think the stm32 stuff looks pretty OK, so we can take that
> before the SFDP stuff, no?
>


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH 0/2] mtd: spi-nor: add stm32 qspi driver

[Cyrille Pitchen]

Hi all,

Le 30/03/2017 à 12:15, Marek Vasut a écrit :
> On 03/30/2017 09:31 AM, Ludovic BARRE wrote:
>> hi Cyrille
>>
>> I see your patch series
>>
>> [PATCH v5 0/6] mtd: spi-nor: parse SFDP tables to setup (Q)SPI memories
>>
>> No problem, I rebase my V2 onto your patch
> 
> I still didn't review that, so it might take a bit until it hits
> mainline. I think the stm32 stuff looks pretty OK, so we can take that
> before the SFDP stuff, no?
> 

About the SFDP patches they are still RFC so yes, they can wait, no
problem with that. Anyway I was working on them this afternoon so they
are not finalized yet.

However the first 3 patches of the series, especially patch
"mtd: spi-nor: introduce more SPI protocols and the Dual Transfer Mode",
are needed as a base to fix other long time pending issues.

Those patches are available from both the github/spi-nor and linux-next
tree. So I think Ludovic can rebase his patches, test them then send v3
to the linux-mtd mailing list with the relevant ChangeLog in the cover
letter.

For your information:
2016-06-20 https://patchwork.ozlabs.org/patch/638138/
2016-10-04 https://patchwork.ozlabs.org/patch/678162/
2016-10-05 https://patchwork.ozlabs.org/patch/678404/
2016-10-24 https://patchwork.ozlabs.org/patch/685981/
2016-11-21 https://patchwork.ozlabs.org/patch/697268/
2017-01-25 https://patchwork.ozlabs.org/patch/719777/
2017-03-22 https://patchwork.ozlabs.org/patch/742376/


Sorry but I think the patch changing the 3rd argument of spi_nor_scan()
has precedence over newer patches in the queue to be mainlined.

Best regards,

Cyrille


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[PATCH 2/2] mtd: spi-nor: add driver for STM32 quad spi flash controller

[Ludovic Barre]

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

The quadspi is a specialized communication interface targeting single,
dual or quad SPI Flash memories.

It can operate in any of the following modes:
-indirect mode: all the operations are performed using the quadspi
 registers
-read memory-mapped mode: the external Flash memory is mapped to the
 microcontroller address space and is seen by the system as if it was
 an internal memory

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
---
 drivers/mtd/spi-nor/Kconfig         |   7 +
 drivers/mtd/spi-nor/Makefile        |   1 +
 drivers/mtd/spi-nor/stm32-quadspi.c | 679 ++++++++++++++++++++++++++++++++++++
 3 files changed, 687 insertions(+)
 create mode 100644 drivers/mtd/spi-nor/stm32-quadspi.c

diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
index 7252087..bfdfb1e 100644
--- a/drivers/mtd/spi-nor/Kconfig
+++ b/drivers/mtd/spi-nor/Kconfig
@@ -106,4 +106,11 @@ config SPI_INTEL_SPI_PLATFORM
 	  To compile this driver as a module, choose M here: the module
 	  will be called intel-spi-platform.
 
+config SPI_STM32_QUADSPI
+	tristate "STM32 Quad SPI controller"
+	depends on ARCH_STM32
+	help
+	  This enables support for the STM32 Quad SPI controller.
+	  We only connect the NOR to this controller.
+
 endif # MTD_SPI_NOR
diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
index 72238a7..285aab8 100644
--- a/drivers/mtd/spi-nor/Makefile
+++ b/drivers/mtd/spi-nor/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_MTD_MT81xx_NOR)    += mtk-quadspi.o
 obj-$(CONFIG_SPI_NXP_SPIFI)	+= nxp-spifi.o
 obj-$(CONFIG_SPI_INTEL_SPI)	+= intel-spi.o
 obj-$(CONFIG_SPI_INTEL_SPI_PLATFORM)	+= intel-spi-platform.o
+obj-$(CONFIG_SPI_STM32_QUADSPI)	+= stm32-quadspi.o
\ No newline at end of file
diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
new file mode 100644
index 0000000..c5217a7
--- /dev/null
+++ b/drivers/mtd/spi-nor/stm32-quadspi.c
@@ -0,0 +1,679 @@
+/*
+ * stm32_quadspi.c
+ *
+ * Copyright (C) 2017, Ludovic Barre
+ *
+ * License terms: GNU General Public License (GPL), version 2
+ */
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/spi-nor.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#define QUADSPI_CR		0x00
+#define CR_EN			BIT(0)
+#define CR_ABORT		BIT(1)
+#define CR_DMAEN		BIT(2)
+#define CR_TCEN			BIT(3)
+#define CR_SSHIFT		BIT(4)
+#define CR_DFM			BIT(6)
+#define CR_FSEL			BIT(7)
+#define CR_FTHRES_SHIFT		8
+#define CR_FTHRES_MASK		GENMASK(12, 8)
+#define CR_FTHRES(n)		(((n) << CR_FTHRES_SHIFT) & CR_FTHRES_MASK)
+#define CR_TEIE			BIT(16)
+#define CR_TCIE			BIT(17)
+#define CR_FTIE			BIT(18)
+#define CR_SMIE			BIT(19)
+#define CR_TOIE			BIT(20)
+#define CR_PRESC_SHIFT		24
+#define CR_PRESC_MASK		GENMASK(31, 24)
+#define CR_PRESC(n)		(((n) << CR_PRESC_SHIFT) & CR_PRESC_MASK)
+
+#define QUADSPI_DCR		0x04
+#define DCR_CSHT_SHIFT		8
+#define DCR_CSHT_MASK		GENMASK(10, 8)
+#define DCR_CSHT(n)		(((n) << DCR_CSHT_SHIFT) & DCR_CSHT_MASK)
+#define DCR_FSIZE_SHIFT		16
+#define DCR_FSIZE_MASK		GENMASK(20, 16)
+#define DCR_FSIZE(n)		(((n) << DCR_FSIZE_SHIFT) & DCR_FSIZE_MASK)
+
+#define QUADSPI_SR		0x08
+#define SR_TEF			BIT(0)
+#define SR_TCF			BIT(1)
+#define SR_FTF			BIT(2)
+#define SR_SMF			BIT(3)
+#define SR_TOF			BIT(4)
+#define SR_BUSY			BIT(5)
+#define SR_FLEVEL_SHIFT		8
+#define SR_FLEVEL_MASK		GENMASK(13, 8)
+
+#define QUADSPI_FCR		0x0c
+#define FCR_CTCF		BIT(1)
+
+#define QUADSPI_DLR		0x10
+
+#define QUADSPI_CCR		0x14
+#define CCR_INST_SHIFT		0
+#define CCR_INST_MASK		GENMASK(7, 0)
+#define CCR_INST(n)		(((n) << CCR_INST_SHIFT) & CCR_INST_MASK)
+#define CCR_IMODE_NONE		(0 << 8)
+#define CCR_IMODE_1		(1 << 8)
+#define CCR_IMODE_2		(2 << 8)
+#define CCR_IMODE_4		(3 << 8)
+#define CCR_ADMODE_NONE		(0 << 10)
+#define CCR_ADMODE_1		(1 << 10)
+#define CCR_ADMODE_2		(2 << 10)
+#define CCR_ADMODE_4		(3 << 10)
+#define CCR_ADSIZE_SHIFT	12
+#define CCR_ADSIZE_MASK		GENMASK(13, 12)
+#define CCR_ADSIZE(n)		(((n) << CCR_ADSIZE_SHIFT) & CCR_ADSIZE_MASK)
+#define CCR_ABMODE_NONE		(0 << 14)
+#define CCR_ABMODE_1		(1 << 14)
+#define CCR_ABMODE_2		(2 << 14)
+#define CCR_ABMODE_4		(3 << 14)
+#define CCR_ABSIZE_8		(0 << 16)
+#define CCR_ABSIZE_16		(1 << 16)
+#define CCR_ABSIZE_24		(2 << 16)
+#define CCR_ABSIZE_32		(3 << 16)
+#define CCR_DCYC_SHIFT		18
+#define CCR_DCYC_MASK		GENMASK(22, 18)
+#define CCR_DCYC(n)		(((n) << CCR_DCYC_SHIFT) & CCR_DCYC_MASK)
+#define CCR_DMODE_NONE		(0 << 24)
+#define CCR_DMODE_1		(1 << 24)
+#define CCR_DMODE_2		(2 << 24)
+#define CCR_DMODE_4		(3 << 24)
+#define CCR_FMODE_INDW		(0 << 26)
+#define CCR_FMODE_INDR		(1 << 26)
+#define CCR_FMODE_APM		(2 << 26)
+#define CCR_FMODE_MM		(3 << 26)
+
+#define QUADSPI_AR		0x18
+#define QUADSPI_ABR		0x1c
+#define QUADSPI_DR		0x20
+#define QUADSPI_PSMKR		0x24
+#define QUADSPI_PSMAR		0x28
+#define QUADSPI_PIR		0x2c
+#define QUADSPI_LPTR		0x30
+#define LPTR_DFT_TIMEOUT	0x10
+
+#define STM32_MAX_MMAP_SZ	SZ_256M
+#define STM32_MAX_NORCHIP	2
+
+struct stm32_qspi_flash {
+	struct spi_nor nor;
+	u32 cs;
+	u32 fsize;
+	u32 presc;
+	struct stm32_qspi *qspi;
+};
+
+struct stm32_qspi {
+	struct device *dev;
+	void __iomem *io_base;
+	void __iomem *mm_base;
+	u32 nor_num;
+	struct clk *clk;
+	u32 clk_rate;
+	struct stm32_qspi_flash flash[STM32_MAX_NORCHIP];
+	u32 read_mode;
+	struct completion cmd_completion;
+
+	/*
+	 * to protect device configuration, could be different between
+	 * 2 flash access (bk1, bk2)
+	 */
+	struct mutex lock;
+};
+
+struct stm32_qspi_cmd {
+	struct {
+		u32 addr_width:8;
+		u32 dummy:8;
+		u32 data:1;
+	} conf;
+
+	u8 opcode;
+	u32 framemode;
+	u32 qspimode;
+	u32 addr;
+	size_t len;
+	void *buf;
+};
+
+static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi)
+{
+	u32 cr;
+	int err = 0;
+
+	if (readl_relaxed(qspi->io_base + QUADSPI_SR) & SR_TCF)
+		return 0;
+
+	reinit_completion(&qspi->cmd_completion);
+	cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
+	writel_relaxed(cr | CR_TCIE, qspi->io_base + QUADSPI_CR);
+
+	if (!wait_for_completion_interruptible_timeout(&qspi->cmd_completion,
+						       msecs_to_jiffies(1000)))
+		err = -ETIMEDOUT;
+
+	writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
+	return err;
+}
+
+static int stm32_qspi_wait_nobusy(struct stm32_qspi *qspi)
+{
+	u32 sr;
+
+	return readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR, sr,
+					  !(sr & SR_BUSY), 10, 100000);
+}
+
+static void stm32_qspi_set_framemode(struct spi_nor *nor,
+				     struct stm32_qspi_cmd *cmd, bool read)
+{
+	u32 dmode = CCR_DMODE_1;
+
+	cmd->framemode = CCR_IMODE_1;
+
+	if (read) {
+		switch (nor->flash_read) {
+		case SPI_NOR_NORMAL:
+		case SPI_NOR_FAST:
+			dmode = CCR_DMODE_1;
+			break;
+		case SPI_NOR_DUAL:
+			dmode = CCR_DMODE_2;
+			break;
+		case SPI_NOR_QUAD:
+			dmode = CCR_DMODE_4;
+			break;
+		}
+	}
+
+	cmd->framemode |= cmd->conf.data ? dmode : 0;
+	cmd->framemode |= cmd->conf.addr_width ? CCR_ADMODE_1 : 0;
+}
+
+static void stm32_qspi_read_fifo(u8 *val, void __iomem *addr)
+{
+	*val = readb_relaxed(addr);
+}
+
+static void stm32_qspi_write_fifo(u8 *val, void __iomem *addr)
+{
+	writeb_relaxed(*val, addr);
+}
+
+static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
+			      const struct stm32_qspi_cmd *cmd)
+{
+	void (*tx_fifo)(u8 *, void __iomem *);
+	u32 len = cmd->len, sr;
+	u8 *buf = cmd->buf;
+	int ret;
+
+	if (cmd->qspimode == CCR_FMODE_INDW)
+		tx_fifo = stm32_qspi_write_fifo;
+	else
+		tx_fifo = stm32_qspi_read_fifo;
+
+	while (len--) {
+		ret = readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR,
+						 sr, (sr & SR_FTF),
+						 10, 30000);
+		if (ret) {
+			dev_err(qspi->dev, "fifo timeout (stat:%#x)\n", sr);
+			break;
+		}
+		tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
+	}
+
+	return ret;
+}
+
+static int stm32_qspi_tx_mm(struct stm32_qspi *qspi,
+			    const struct stm32_qspi_cmd *cmd)
+{
+	memcpy_fromio(cmd->buf, qspi->mm_base + cmd->addr, cmd->len);
+	return 0;
+}
+
+static int stm32_qspi_tx(struct stm32_qspi *qspi,
+			 const struct stm32_qspi_cmd *cmd)
+{
+	if (!cmd->conf.data)
+		return 0;
+
+	if (cmd->qspimode == CCR_FMODE_MM)
+		return stm32_qspi_tx_mm(qspi, cmd);
+
+	return stm32_qspi_tx_poll(qspi, cmd);
+}
+
+static int stm32_qspi_send(struct stm32_qspi_flash *flash,
+			   const struct stm32_qspi_cmd *cmd)
+{
+	struct stm32_qspi *qspi = flash->qspi;
+	u32 ccr, dcr, cr;
+	int err;
+
+	err = stm32_qspi_wait_nobusy(qspi);
+	if (err)
+		goto abort;
+
+	dcr = readl_relaxed(qspi->io_base + QUADSPI_DCR) & ~DCR_FSIZE_MASK;
+	dcr |= DCR_FSIZE(flash->fsize);
+	writel_relaxed(dcr, qspi->io_base + QUADSPI_DCR);
+
+	cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
+	cr &= ~CR_PRESC_MASK & ~CR_FSEL;
+	cr |= CR_PRESC(flash->presc);
+	cr |= flash->cs ? CR_FSEL : 0;
+	writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
+
+	if (cmd->conf.data)
+		writel_relaxed(cmd->len - 1, qspi->io_base + QUADSPI_DLR);
+
+	ccr = cmd->framemode | cmd->qspimode;
+
+	if (cmd->conf.dummy)
+		ccr |= CCR_DCYC(cmd->conf.dummy);
+
+	if (cmd->conf.addr_width)
+		ccr |= CCR_ADSIZE(cmd->conf.addr_width - 1);
+
+	ccr |= CCR_INST(cmd->opcode);
+	writel_relaxed(ccr, qspi->io_base + QUADSPI_CCR);
+
+	if (cmd->conf.addr_width && cmd->qspimode != CCR_FMODE_MM)
+		writel_relaxed(cmd->addr, qspi->io_base + QUADSPI_AR);
+
+	err = stm32_qspi_tx(qspi, cmd);
+	if (err)
+		goto abort;
+
+	if (cmd->qspimode != CCR_FMODE_MM) {
+		err = stm32_qspi_wait_cmd(qspi);
+		if (err)
+			goto abort;
+		writel_relaxed(FCR_CTCF, qspi->io_base + QUADSPI_FCR);
+	}
+
+	return err;
+
+abort:
+	writel_relaxed(readl_relaxed(qspi->io_base + QUADSPI_CR)
+		       | CR_ABORT, qspi->io_base + QUADSPI_CR);
+
+	dev_err(qspi->dev, "%s abort err:%d\n", __func__, err);
+	return err;
+}
+
+static int stm32_qspi_read_reg(struct spi_nor *nor,
+			       u8 opcode, u8 *buf, int len)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct device *dev = flash->qspi->dev;
+	struct stm32_qspi_cmd cmd;
+
+	dev_dbg(dev, "read_reg: cmd:%.2x buf:%p len:%d\n", opcode, buf, len);
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = opcode;
+	cmd.conf.data = 1;
+	cmd.len = len;
+	cmd.buf = buf;
+	cmd.qspimode = CCR_FMODE_INDR;
+
+	stm32_qspi_set_framemode(nor, &cmd, false);
+
+	return stm32_qspi_send(flash, &cmd);
+}
+
+static int stm32_qspi_write_reg(struct spi_nor *nor, u8 opcode,
+				u8 *buf, int len)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct device *dev = flash->qspi->dev;
+	struct stm32_qspi_cmd cmd;
+
+	dev_dbg(dev, "write_reg: cmd:%.2x buf:%p len:%d\n", opcode, buf, len);
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = opcode;
+	cmd.conf.data = (buf && len > 0);
+	cmd.len = len;
+	cmd.buf = buf;
+	cmd.qspimode = CCR_FMODE_INDW;
+
+	stm32_qspi_set_framemode(nor, &cmd, false);
+
+	return stm32_qspi_send(flash, &cmd);
+}
+
+static ssize_t stm32_qspi_read(struct spi_nor *nor, loff_t from, size_t len,
+			       u_char *buf)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct stm32_qspi *qspi = flash->qspi;
+	struct stm32_qspi_cmd cmd;
+	int err;
+
+	dev_dbg(qspi->dev, "read(%#.2x): buf:%p from:%#.8x len:%#x\n",
+		nor->read_opcode, buf, (u32)from, len);
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = nor->read_opcode;
+	cmd.conf.addr_width = nor->addr_width;
+	cmd.addr = (u32)from;
+	cmd.conf.data = 1;
+	cmd.conf.dummy = nor->read_dummy;
+	cmd.len = len;
+	cmd.buf = buf;
+	cmd.qspimode = qspi->read_mode;
+
+	stm32_qspi_set_framemode(nor, &cmd, true);
+	err = stm32_qspi_send(flash, &cmd);
+
+	return err ? err : len;
+}
+
+static ssize_t stm32_qspi_write(struct spi_nor *nor, loff_t to, size_t len,
+				const u_char *buf)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct device *dev = flash->qspi->dev;
+	struct stm32_qspi_cmd cmd;
+	int err;
+
+	dev_dbg(dev, "write(%#.2x): buf:%p to:%#.8x len:%#x\n",
+		nor->program_opcode, buf, (u32)to, len);
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = nor->program_opcode;
+	cmd.conf.addr_width = nor->addr_width;
+	cmd.addr = (u32)to;
+	cmd.conf.data = 1;
+	cmd.len = len;
+	cmd.buf = (void *)buf;
+	cmd.qspimode = CCR_FMODE_INDW;
+
+	stm32_qspi_set_framemode(nor, &cmd, false);
+	err = stm32_qspi_send(flash, &cmd);
+
+	return err ? err : len;
+}
+
+static int stm32_qspi_erase(struct spi_nor *nor, loff_t offs)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct device *dev = flash->qspi->dev;
+	struct stm32_qspi_cmd cmd;
+
+	dev_dbg(dev, "erase(%#.2x):offs:%#x\n", nor->erase_opcode, (u32)offs);
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = nor->erase_opcode;
+	cmd.conf.addr_width = nor->addr_width;
+	cmd.addr = (u32)offs;
+	cmd.qspimode = CCR_FMODE_INDW;
+
+	stm32_qspi_set_framemode(nor, &cmd, false);
+
+	return stm32_qspi_send(flash, &cmd);
+}
+
+static irqreturn_t stm32_qspi_irq(int irq, void *dev_id)
+{
+	struct stm32_qspi *qspi = (struct stm32_qspi *)dev_id;
+	u32 cr, sr, fcr = 0;
+
+	cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
+	sr = readl_relaxed(qspi->io_base + QUADSPI_SR);
+
+	if ((cr & CR_TCIE) && (sr & SR_TCF)) {
+		/* tx complete */
+		fcr |= FCR_CTCF;
+		complete(&qspi->cmd_completion);
+	} else {
+		dev_info(qspi->dev, "spurious interrupt\n");
+	}
+
+	writel_relaxed(fcr, qspi->io_base + QUADSPI_FCR);
+
+	return IRQ_HANDLED;
+}
+
+static int stm32_qspi_prep(struct spi_nor *nor, enum spi_nor_ops ops)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct stm32_qspi *qspi = flash->qspi;
+
+	mutex_lock(&qspi->lock);
+	return 0;
+}
+
+static void stm32_qspi_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct stm32_qspi *qspi = flash->qspi;
+
+	mutex_unlock(&qspi->lock);
+}
+
+static int stm32_qspi_flash_setup(struct stm32_qspi *qspi,
+				  struct device_node *np)
+{
+	u32 width, flash_read, presc, cs_num, max_rate = 0;
+	struct stm32_qspi_flash *flash;
+	struct mtd_info *mtd;
+	int ret;
+
+	of_property_read_u32(np, "reg", &cs_num);
+	if (cs_num >= STM32_MAX_NORCHIP)
+		return -EINVAL;
+
+	of_property_read_u32(np, "spi-max-frequency", &max_rate);
+	if (!max_rate)
+		return -EINVAL;
+
+	presc = DIV_ROUND_UP(qspi->clk_rate, max_rate) - 1;
+
+	if (of_property_read_u32(np, "spi-rx-bus-width", &width))
+		width = 1;
+
+	if (width == 4)
+		flash_read = SPI_NOR_QUAD;
+	else if (width == 2)
+		flash_read = SPI_NOR_DUAL;
+	else if (width == 1)
+		flash_read = SPI_NOR_NORMAL;
+	else
+		return -EINVAL;
+
+	flash = &qspi->flash[cs_num];
+	flash->qspi = qspi;
+	flash->cs = cs_num;
+	flash->presc = presc;
+
+	flash->nor.dev = qspi->dev;
+	spi_nor_set_flash_node(&flash->nor, np);
+	flash->nor.priv = flash;
+	mtd = &flash->nor.mtd;
+	mtd->priv = &flash->nor;
+
+	flash->nor.read = stm32_qspi_read;
+	flash->nor.write = stm32_qspi_write;
+	flash->nor.erase = stm32_qspi_erase;
+	flash->nor.read_reg = stm32_qspi_read_reg;
+	flash->nor.write_reg = stm32_qspi_write_reg;
+	flash->nor.prepare = stm32_qspi_prep;
+	flash->nor.unprepare = stm32_qspi_unprep;
+
+	writel_relaxed(LPTR_DFT_TIMEOUT, qspi->io_base + QUADSPI_LPTR);
+
+	writel_relaxed(CR_PRESC(presc) | CR_FTHRES(3) | CR_TCEN | CR_SSHIFT
+		       | CR_EN, qspi->io_base + QUADSPI_CR);
+
+	/* a minimum fsize must be set to sent the command id */
+	flash->fsize = 25;
+
+	ret = spi_nor_scan(&flash->nor, NULL, flash_read);
+	if (ret) {
+		dev_err(qspi->dev, "device scan failed\n");
+		return ret;
+	}
+
+	flash->fsize = __fls(mtd->size) - 1;
+
+	writel_relaxed(DCR_CSHT(1), qspi->io_base + QUADSPI_DCR);
+
+	ret = mtd_device_register(mtd, NULL, 0);
+	if (ret) {
+		dev_err(qspi->dev, "mtd device parse failed\n");
+		return ret;
+	}
+
+	dev_dbg(qspi->dev, "read mm:%s cs:%d bus:%d\n",
+		qspi->read_mode == CCR_FMODE_MM ? "yes" : "no", cs_num, width);
+
+	return 0;
+}
+
+static void stm32_qspi_mtd_free(struct stm32_qspi *qspi)
+{
+	int i;
+
+	for (i = 0; i < STM32_MAX_NORCHIP; i++) {
+		if (qspi->flash[i].qspi)
+			mtd_device_unregister(&qspi->flash[i].nor.mtd);
+	}
+}
+
+static int stm32_qspi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *flash_np;
+	struct reset_control *rstc;
+	struct stm32_qspi *qspi;
+	struct resource *res;
+	int ret, irq;
+
+	qspi = devm_kzalloc(dev, sizeof(*qspi), GFP_KERNEL);
+	if (!qspi)
+		return -ENOMEM;
+
+	qspi->nor_num = of_get_child_count(dev->of_node);
+	if (!qspi->nor_num || qspi->nor_num > STM32_MAX_NORCHIP)
+		return -ENODEV;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi");
+	qspi->io_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(qspi->io_base))
+		return PTR_ERR(qspi->io_base);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_mm");
+	if (res && resource_size(res) <= STM32_MAX_MMAP_SZ)
+		qspi->mm_base = devm_ioremap_resource(dev, res);
+
+	qspi->read_mode = IS_ERR_OR_NULL(qspi->mm_base) ?
+		CCR_FMODE_INDR : CCR_FMODE_MM;
+
+	irq = platform_get_irq(pdev, 0);
+	ret = devm_request_irq(dev, irq, stm32_qspi_irq, 0,
+			       dev_name(dev), qspi);
+	if (ret) {
+		dev_err(dev, "failed to request irq\n");
+		return ret;
+	}
+
+	init_completion(&qspi->cmd_completion);
+
+	qspi->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(qspi->clk))
+		return PTR_ERR(qspi->clk);
+
+	qspi->clk_rate = clk_get_rate(qspi->clk);
+	if (!qspi->clk_rate)
+		return -EINVAL;
+
+	ret = clk_prepare_enable(qspi->clk);
+	if (ret) {
+		dev_err(dev, "can not enable the clock\n");
+		return ret;
+	}
+
+	rstc = devm_reset_control_get(dev, NULL);
+	if (!IS_ERR(rstc)) {
+		reset_control_assert(rstc);
+		udelay(2);
+		reset_control_deassert(rstc);
+	}
+
+	qspi->dev = dev;
+	platform_set_drvdata(pdev, qspi);
+	mutex_init(&qspi->lock);
+
+	for_each_available_child_of_node(dev->of_node, flash_np) {
+		ret = stm32_qspi_flash_setup(qspi, flash_np);
+		if (ret) {
+			dev_err(dev, "unable to setup flash chip\n");
+			goto err_flash;
+		}
+	}
+
+	return 0;
+
+err_flash:
+	mutex_destroy(&qspi->lock);
+	stm32_qspi_mtd_free(qspi);
+
+	clk_disable_unprepare(qspi->clk);
+	return ret;
+}
+
+static int stm32_qspi_remove(struct platform_device *pdev)
+{
+	struct stm32_qspi *qspi = platform_get_drvdata(pdev);
+
+	/* disable qspi */
+	writel_relaxed(0, qspi->io_base + QUADSPI_CR);
+
+	stm32_qspi_mtd_free(qspi);
+	mutex_destroy(&qspi->lock);
+
+	clk_disable_unprepare(qspi->clk);
+	return 0;
+}
+
+static const struct of_device_id stm32_qspi_match[] = {
+	{.compatible = "st,stm32f469-qspi"},
+	{}
+};
+MODULE_DEVICE_TABLE(of, stm32_qspi_match);
+
+static struct platform_driver stm32_qspi_driver = {
+	.probe	= stm32_qspi_probe,
+	.remove	= stm32_qspi_remove,
+	.driver	= {
+		.name = "stm32-quadspi",
+		.of_match_table = stm32_qspi_match,
+	},
+};
+module_platform_driver(stm32_qspi_driver);
+
+MODULE_ALIAS("platform:" DRIVER_NAME);
+MODULE_AUTHOR("Ludovic Barre <ludovic.barre@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 quad spi driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH 2/2] mtd: spi-nor: add driver for STM32 quad spi flash controller

[Marek Vasut]

On 03/27/2017 02:54 PM, Ludovic Barre wrote:
> From: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
> 
> The quadspi is a specialized communication interface targeting single,
> dual or quad SPI Flash memories.
> 
> It can operate in any of the following modes:
> -indirect mode: all the operations are performed using the quadspi
>  registers
> -read memory-mapped mode: the external Flash memory is mapped to the
>  microcontroller address space and is seen by the system as if it was
>  an internal memory
> 
> Signed-off-by: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>

Hi! I presume this is not compatible with the Cadence QSPI or any other
QSPI controller, huh ?

Mostly minor nits below ...

> ---
>  drivers/mtd/spi-nor/Kconfig         |   7 +
>  drivers/mtd/spi-nor/Makefile        |   1 +
>  drivers/mtd/spi-nor/stm32-quadspi.c | 679 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 687 insertions(+)
>  create mode 100644 drivers/mtd/spi-nor/stm32-quadspi.c

[...]

> +struct stm32_qspi_cmd {
> +	struct {
> +		u32 addr_width:8;
> +		u32 dummy:8;
> +		u32 data:1;
> +	} conf;

This could all be u8 ? Why this awful construct ?

> +	u8 opcode;
> +	u32 framemode;
> +	u32 qspimode;
> +	u32 addr;
> +	size_t len;
> +	void *buf;
> +};
> +
> +static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi)
> +{
> +	u32 cr;
> +	int err = 0;

Can readl_poll_timeout() or somesuch replace this function ?

> +	if (readl_relaxed(qspi->io_base + QUADSPI_SR) & SR_TCF)
> +		return 0;
> +
> +	reinit_completion(&qspi->cmd_completion);
> +	cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
> +	writel_relaxed(cr | CR_TCIE, qspi->io_base + QUADSPI_CR);
> +
> +	if (!wait_for_completion_interruptible_timeout(&qspi->cmd_completion,
> +						       msecs_to_jiffies(1000)))
> +		err = -ETIMEDOUT;
> +
> +	writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
> +	return err;
> +}
> +
> +static int stm32_qspi_wait_nobusy(struct stm32_qspi *qspi)
> +{
> +	u32 sr;
> +
> +	return readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR, sr,
> +					  !(sr & SR_BUSY), 10, 100000);
> +}
> +
> +static void stm32_qspi_set_framemode(struct spi_nor *nor,
> +				     struct stm32_qspi_cmd *cmd, bool read)
> +{
> +	u32 dmode = CCR_DMODE_1;
> +
> +	cmd->framemode = CCR_IMODE_1;
> +
> +	if (read) {
> +		switch (nor->flash_read) {
> +		case SPI_NOR_NORMAL:
> +		case SPI_NOR_FAST:
> +			dmode = CCR_DMODE_1;
> +			break;
> +		case SPI_NOR_DUAL:
> +			dmode = CCR_DMODE_2;
> +			break;
> +		case SPI_NOR_QUAD:
> +			dmode = CCR_DMODE_4;
> +			break;
> +		}
> +	}
> +
> +	cmd->framemode |= cmd->conf.data ? dmode : 0;
> +	cmd->framemode |= cmd->conf.addr_width ? CCR_ADMODE_1 : 0;
> +}
> +
> +static void stm32_qspi_read_fifo(u8 *val, void __iomem *addr)
> +{
> +	*val = readb_relaxed(addr);
> +}
> +
> +static void stm32_qspi_write_fifo(u8 *val, void __iomem *addr)
> +{
> +	writeb_relaxed(*val, addr);
> +}
> +
> +static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
> +			      const struct stm32_qspi_cmd *cmd)
> +{
> +	void (*tx_fifo)(u8 *, void __iomem *);
> +	u32 len = cmd->len, sr;
> +	u8 *buf = cmd->buf;
> +	int ret;
> +
> +	if (cmd->qspimode == CCR_FMODE_INDW)
> +		tx_fifo = stm32_qspi_write_fifo;
> +	else
> +		tx_fifo = stm32_qspi_read_fifo;
> +
> +	while (len--) {
> +		ret = readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR,
> +						 sr, (sr & SR_FTF),
> +						 10, 30000);

Add macros for those ad-hoc timeouts.

> +		if (ret) {
> +			dev_err(qspi->dev, "fifo timeout (stat:%#x)\n", sr);
> +			break;
> +		}
> +		tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
> +	}
> +
> +	return ret;
> +}


[...]

> +static int stm32_qspi_send(struct stm32_qspi_flash *flash,
> +			   const struct stm32_qspi_cmd *cmd)
> +{
> +	struct stm32_qspi *qspi = flash->qspi;
> +	u32 ccr, dcr, cr;
> +	int err;
> +
> +	err = stm32_qspi_wait_nobusy(qspi);
> +	if (err)
> +		goto abort;
> +
> +	dcr = readl_relaxed(qspi->io_base + QUADSPI_DCR) & ~DCR_FSIZE_MASK;
> +	dcr |= DCR_FSIZE(flash->fsize);
> +	writel_relaxed(dcr, qspi->io_base + QUADSPI_DCR);
> +
> +	cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
> +	cr &= ~CR_PRESC_MASK & ~CR_FSEL;
> +	cr |= CR_PRESC(flash->presc);
> +	cr |= flash->cs ? CR_FSEL : 0;
> +	writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
> +
> +	if (cmd->conf.data)
> +		writel_relaxed(cmd->len - 1, qspi->io_base + QUADSPI_DLR);
> +
> +	ccr = cmd->framemode | cmd->qspimode;
> +
> +	if (cmd->conf.dummy)
> +		ccr |= CCR_DCYC(cmd->conf.dummy);
> +
> +	if (cmd->conf.addr_width)
> +		ccr |= CCR_ADSIZE(cmd->conf.addr_width - 1);
> +
> +	ccr |= CCR_INST(cmd->opcode);
> +	writel_relaxed(ccr, qspi->io_base + QUADSPI_CCR);
> +
> +	if (cmd->conf.addr_width && cmd->qspimode != CCR_FMODE_MM)
> +		writel_relaxed(cmd->addr, qspi->io_base + QUADSPI_AR);
> +
> +	err = stm32_qspi_tx(qspi, cmd);
> +	if (err)
> +		goto abort;
> +
> +	if (cmd->qspimode != CCR_FMODE_MM) {
> +		err = stm32_qspi_wait_cmd(qspi);
> +		if (err)
> +			goto abort;
> +		writel_relaxed(FCR_CTCF, qspi->io_base + QUADSPI_FCR);
> +	}
> +
> +	return err;
> +
> +abort:
> +	writel_relaxed(readl_relaxed(qspi->io_base + QUADSPI_CR)
> +		       | CR_ABORT, qspi->io_base + QUADSPI_CR);

Use a helper variable here too.

> +	dev_err(qspi->dev, "%s abort err:%d\n", __func__, err);
> +	return err;
> +}

[...]

> +static int stm32_qspi_flash_setup(struct stm32_qspi *qspi,
> +				  struct device_node *np)
> +{
> +	u32 width, flash_read, presc, cs_num, max_rate = 0;
> +	struct stm32_qspi_flash *flash;
> +	struct mtd_info *mtd;
> +	int ret;
> +
> +	of_property_read_u32(np, "reg", &cs_num);
> +	if (cs_num >= STM32_MAX_NORCHIP)
> +		return -EINVAL;
> +
> +	of_property_read_u32(np, "spi-max-frequency", &max_rate);
> +	if (!max_rate)
> +		return -EINVAL;
> +
> +	presc = DIV_ROUND_UP(qspi->clk_rate, max_rate) - 1;
> +
> +	if (of_property_read_u32(np, "spi-rx-bus-width", &width))
> +		width = 1;
> +
> +	if (width == 4)
> +		flash_read = SPI_NOR_QUAD;
> +	else if (width == 2)
> +		flash_read = SPI_NOR_DUAL;
> +	else if (width == 1)
> +		flash_read = SPI_NOR_NORMAL;
> +	else
> +		return -EINVAL;
> +
> +	flash = &qspi->flash[cs_num];
> +	flash->qspi = qspi;
> +	flash->cs = cs_num;
> +	flash->presc = presc;
> +
> +	flash->nor.dev = qspi->dev;
> +	spi_nor_set_flash_node(&flash->nor, np);
> +	flash->nor.priv = flash;
> +	mtd = &flash->nor.mtd;
> +	mtd->priv = &flash->nor;
> +
> +	flash->nor.read = stm32_qspi_read;
> +	flash->nor.write = stm32_qspi_write;
> +	flash->nor.erase = stm32_qspi_erase;
> +	flash->nor.read_reg = stm32_qspi_read_reg;
> +	flash->nor.write_reg = stm32_qspi_write_reg;
> +	flash->nor.prepare = stm32_qspi_prep;
> +	flash->nor.unprepare = stm32_qspi_unprep;
> +
> +	writel_relaxed(LPTR_DFT_TIMEOUT, qspi->io_base + QUADSPI_LPTR);
> +
> +	writel_relaxed(CR_PRESC(presc) | CR_FTHRES(3) | CR_TCEN | CR_SSHIFT
> +		       | CR_EN, qspi->io_base + QUADSPI_CR);
> +
> +	/* a minimum fsize must be set to sent the command id */
> +	flash->fsize = 25;

I don't understand why this is needed and the comment doesn't make
sense. Please fix.

> +	ret = spi_nor_scan(&flash->nor, NULL, flash_read);
> +	if (ret) {
> +		dev_err(qspi->dev, "device scan failed\n");
> +		return ret;
> +	}
> +
> +	flash->fsize = __fls(mtd->size) - 1;
> +
> +	writel_relaxed(DCR_CSHT(1), qspi->io_base + QUADSPI_DCR);
> +
> +	ret = mtd_device_register(mtd, NULL, 0);
> +	if (ret) {
> +		dev_err(qspi->dev, "mtd device parse failed\n");
> +		return ret;
> +	}
> +
> +	dev_dbg(qspi->dev, "read mm:%s cs:%d bus:%d\n",
> +		qspi->read_mode == CCR_FMODE_MM ? "yes" : "no", cs_num, width);
> +
> +	return 0;
> +}

[...]

-- 
Best regards,
Marek Vasut
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Re: [PATCH 2/2] mtd: spi-nor: add driver for STM32 quad spi flash controller

[Ludovic BARRE]

hi Marek

thanks for review
comment below

On 03/29/2017 12:54 PM, Marek Vasut wrote:
> On 03/27/2017 02:54 PM, Ludovic Barre wrote:
>> From: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
>>
>> The quadspi is a specialized communication interface targeting single,
>> dual or quad SPI Flash memories.
>>
>> It can operate in any of the following modes:
>> -indirect mode: all the operations are performed using the quadspi
>>   registers
>> -read memory-mapped mode: the external Flash memory is mapped to the
>>   microcontroller address space and is seen by the system as if it was
>>   an internal memory
>>
>> Signed-off-by: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
> Hi! I presume this is not compatible with the Cadence QSPI or any other
> QSPI controller, huh ?
it's not a cadence QSPI, it's specific for stm32 platform
>
> Mostly minor nits below ...
>
>> ---
>>   drivers/mtd/spi-nor/Kconfig         |   7 +
>>   drivers/mtd/spi-nor/Makefile        |   1 +
>>   drivers/mtd/spi-nor/stm32-quadspi.c | 679 ++++++++++++++++++++++++++++++++++++
>>   3 files changed, 687 insertions(+)
>>   create mode 100644 drivers/mtd/spi-nor/stm32-quadspi.c
> [...]
>
>> +struct stm32_qspi_cmd {
>> +	struct {
>> +		u32 addr_width:8;
>> +		u32 dummy:8;
>> +		u32 data:1;
>> +	} conf;
> This could all be u8 ? Why this awful construct ?
yes I could replace each u32 by u8
>
>> +	u8 opcode;
>> +	u32 framemode;
>> +	u32 qspimode;
>> +	u32 addr;
>> +	size_t len;
>> +	void *buf;
>> +};
>> +
>> +static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi)
>> +{
>> +	u32 cr;
>> +	int err = 0;
> Can readl_poll_timeout() or somesuch replace this function ?
in fact stm32_qspi_wait_cmd test if the transfer has been complete (TCF 
flag)
else initialize an interrupt completion.
like the time may be long I prefer keep the interrupt wait, if you agree.
>> +	if (readl_relaxed(qspi->io_base + QUADSPI_SR) & SR_TCF)
>> +		return 0;
>> +
>> +	reinit_completion(&qspi->cmd_completion);
>> +	cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
>> +	writel_relaxed(cr | CR_TCIE, qspi->io_base + QUADSPI_CR);
>> +
>> +	if (!wait_for_completion_interruptible_timeout(&qspi->cmd_completion,
>> +						       msecs_to_jiffies(1000)))
>> +		err = -ETIMEDOUT;
>> +
>> +	writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
>> +	return err;
>> +}
>> +
>> +static int stm32_qspi_wait_nobusy(struct stm32_qspi *qspi)
>> +{
>> +	u32 sr;
>> +
>> +	return readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR, sr,
>> +					  !(sr & SR_BUSY), 10, 100000);
>> +}
>> +
>> +static void stm32_qspi_set_framemode(struct spi_nor *nor,
>> +				     struct stm32_qspi_cmd *cmd, bool read)
>> +{
>> +	u32 dmode = CCR_DMODE_1;
>> +
>> +	cmd->framemode = CCR_IMODE_1;
>> +
>> +	if (read) {
>> +		switch (nor->flash_read) {
>> +		case SPI_NOR_NORMAL:
>> +		case SPI_NOR_FAST:
>> +			dmode = CCR_DMODE_1;
>> +			break;
>> +		case SPI_NOR_DUAL:
>> +			dmode = CCR_DMODE_2;
>> +			break;
>> +		case SPI_NOR_QUAD:
>> +			dmode = CCR_DMODE_4;
>> +			break;
>> +		}
>> +	}
>> +
>> +	cmd->framemode |= cmd->conf.data ? dmode : 0;
>> +	cmd->framemode |= cmd->conf.addr_width ? CCR_ADMODE_1 : 0;
>> +}
>> +
>> +static void stm32_qspi_read_fifo(u8 *val, void __iomem *addr)
>> +{
>> +	*val = readb_relaxed(addr);
>> +}
>> +
>> +static void stm32_qspi_write_fifo(u8 *val, void __iomem *addr)
>> +{
>> +	writeb_relaxed(*val, addr);
>> +}
>> +
>> +static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
>> +			      const struct stm32_qspi_cmd *cmd)
>> +{
>> +	void (*tx_fifo)(u8 *, void __iomem *);
>> +	u32 len = cmd->len, sr;
>> +	u8 *buf = cmd->buf;
>> +	int ret;
>> +
>> +	if (cmd->qspimode == CCR_FMODE_INDW)
>> +		tx_fifo = stm32_qspi_write_fifo;
>> +	else
>> +		tx_fifo = stm32_qspi_read_fifo;
>> +
>> +	while (len--) {
>> +		ret = readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR,
>> +						 sr, (sr & SR_FTF),
>> +						 10, 30000);
> Add macros for those ad-hoc timeouts.
I will add 2 defines (for stm32_qspi_wait_nobusy, stm32_qspi_tx_poll)
#define STM32_QSPI_FIFO_TIMEOUT_US 30000
#define STM32_QSPI_BUSY_TIMEOUT_US 100000
>
>> +		if (ret) {
>> +			dev_err(qspi->dev, "fifo timeout (stat:%#x)\n", sr);
>> +			break;
>> +		}
>> +		tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
>> +	}
>> +
>> +	return ret;
>> +}
>
> [...]
>
>> +static int stm32_qspi_send(struct stm32_qspi_flash *flash,
>> +			   const struct stm32_qspi_cmd *cmd)
>> +{
>> +	struct stm32_qspi *qspi = flash->qspi;
>> +	u32 ccr, dcr, cr;
>> +	int err;
>> +
>> +	err = stm32_qspi_wait_nobusy(qspi);
>> +	if (err)
>> +		goto abort;
>> +
>> +	dcr = readl_relaxed(qspi->io_base + QUADSPI_DCR) & ~DCR_FSIZE_MASK;
>> +	dcr |= DCR_FSIZE(flash->fsize);
>> +	writel_relaxed(dcr, qspi->io_base + QUADSPI_DCR);
>> +
>> +	cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
>> +	cr &= ~CR_PRESC_MASK & ~CR_FSEL;
>> +	cr |= CR_PRESC(flash->presc);
>> +	cr |= flash->cs ? CR_FSEL : 0;
>> +	writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
>> +
>> +	if (cmd->conf.data)
>> +		writel_relaxed(cmd->len - 1, qspi->io_base + QUADSPI_DLR);
>> +
>> +	ccr = cmd->framemode | cmd->qspimode;
>> +
>> +	if (cmd->conf.dummy)
>> +		ccr |= CCR_DCYC(cmd->conf.dummy);
>> +
>> +	if (cmd->conf.addr_width)
>> +		ccr |= CCR_ADSIZE(cmd->conf.addr_width - 1);
>> +
>> +	ccr |= CCR_INST(cmd->opcode);
>> +	writel_relaxed(ccr, qspi->io_base + QUADSPI_CCR);
>> +
>> +	if (cmd->conf.addr_width && cmd->qspimode != CCR_FMODE_MM)
>> +		writel_relaxed(cmd->addr, qspi->io_base + QUADSPI_AR);
>> +
>> +	err = stm32_qspi_tx(qspi, cmd);
>> +	if (err)
>> +		goto abort;
>> +
>> +	if (cmd->qspimode != CCR_FMODE_MM) {
>> +		err = stm32_qspi_wait_cmd(qspi);
>> +		if (err)
>> +			goto abort;
>> +		writel_relaxed(FCR_CTCF, qspi->io_base + QUADSPI_FCR);
>> +	}
>> +
>> +	return err;
>> +
>> +abort:
>> +	writel_relaxed(readl_relaxed(qspi->io_base + QUADSPI_CR)
>> +		       | CR_ABORT, qspi->io_base + QUADSPI_CR);
> Use a helper variable here too.
ok
>> +	dev_err(qspi->dev, "%s abort err:%d\n", __func__, err);
>> +	return err;
>> +}
> [...]
>
>> +static int stm32_qspi_flash_setup(struct stm32_qspi *qspi,
>> +				  struct device_node *np)
>> +{
>> +	u32 width, flash_read, presc, cs_num, max_rate = 0;
>> +	struct stm32_qspi_flash *flash;
>> +	struct mtd_info *mtd;
>> +	int ret;
>> +
>> +	of_property_read_u32(np, "reg", &cs_num);
>> +	if (cs_num >= STM32_MAX_NORCHIP)
>> +		return -EINVAL;
>> +
>> +	of_property_read_u32(np, "spi-max-frequency", &max_rate);
>> +	if (!max_rate)
>> +		return -EINVAL;
>> +
>> +	presc = DIV_ROUND_UP(qspi->clk_rate, max_rate) - 1;
>> +
>> +	if (of_property_read_u32(np, "spi-rx-bus-width", &width))
>> +		width = 1;
>> +
>> +	if (width == 4)
>> +		flash_read = SPI_NOR_QUAD;
>> +	else if (width == 2)
>> +		flash_read = SPI_NOR_DUAL;
>> +	else if (width == 1)
>> +		flash_read = SPI_NOR_NORMAL;
>> +	else
>> +		return -EINVAL;
>> +
>> +	flash = &qspi->flash[cs_num];
>> +	flash->qspi = qspi;
>> +	flash->cs = cs_num;
>> +	flash->presc = presc;
>> +
>> +	flash->nor.dev = qspi->dev;
>> +	spi_nor_set_flash_node(&flash->nor, np);
>> +	flash->nor.priv = flash;
>> +	mtd = &flash->nor.mtd;
>> +	mtd->priv = &flash->nor;
>> +
>> +	flash->nor.read = stm32_qspi_read;
>> +	flash->nor.write = stm32_qspi_write;
>> +	flash->nor.erase = stm32_qspi_erase;
>> +	flash->nor.read_reg = stm32_qspi_read_reg;
>> +	flash->nor.write_reg = stm32_qspi_write_reg;
>> +	flash->nor.prepare = stm32_qspi_prep;
>> +	flash->nor.unprepare = stm32_qspi_unprep;
>> +
>> +	writel_relaxed(LPTR_DFT_TIMEOUT, qspi->io_base + QUADSPI_LPTR);
>> +
>> +	writel_relaxed(CR_PRESC(presc) | CR_FTHRES(3) | CR_TCEN | CR_SSHIFT
>> +		       | CR_EN, qspi->io_base + QUADSPI_CR);
>> +
>> +	/* a minimum fsize must be set to sent the command id */
>> +	flash->fsize = 25;
> I don't understand why this is needed and the comment doesn't make
> sense. Please fix.
fsize field defines the size of external memory.
Normaly, this field is used only for memory map mode,
but in fact is check in indirect mode.
So while flash scan "spi_nor_scan":
-I can't let 0.
-I not know yet the size of flash.
So I fix a temporary value

I will update my comment
>
>> +	ret = spi_nor_scan(&flash->nor, NULL, flash_read);
>> +	if (ret) {
>> +		dev_err(qspi->dev, "device scan failed\n");
>> +		return ret;
>> +	}
>> +
>> +	flash->fsize = __fls(mtd->size) - 1;
>> +
>> +	writel_relaxed(DCR_CSHT(1), qspi->io_base + QUADSPI_DCR);
>> +
>> +	ret = mtd_device_register(mtd, NULL, 0);
>> +	if (ret) {
>> +		dev_err(qspi->dev, "mtd device parse failed\n");
>> +		return ret;
>> +	}
>> +
>> +	dev_dbg(qspi->dev, "read mm:%s cs:%d bus:%d\n",
>> +		qspi->read_mode == CCR_FMODE_MM ? "yes" : "no", cs_num, width);
>> +
>> +	return 0;
>> +}
> [...]
>

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Re: [PATCH 2/2] mtd: spi-nor: add driver for STM32 quad spi flash controller

[Marek Vasut]

On 03/29/2017 02:24 PM, Ludovic BARRE wrote:
> hi Marek

Hi!

> thanks for review
> comment below
> 
> On 03/29/2017 12:54 PM, Marek Vasut wrote:
>> On 03/27/2017 02:54 PM, Ludovic Barre wrote:
>>> From: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
>>>
>>> The quadspi is a specialized communication interface targeting single,
>>> dual or quad SPI Flash memories.
>>>
>>> It can operate in any of the following modes:
>>> -indirect mode: all the operations are performed using the quadspi
>>>   registers
>>> -read memory-mapped mode: the external Flash memory is mapped to the
>>>   microcontroller address space and is seen by the system as if it was
>>>   an internal memory
>>>
>>> Signed-off-by: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
>> Hi! I presume this is not compatible with the Cadence QSPI or any other
>> QSPI controller, huh ?
> it's not a cadence QSPI, it's specific for stm32 platform

OK, got it. Didn't ST use Cadence IP somewhere too though ?
That's probably what confused me, oh well ...

>> Mostly minor nits below ...
>>
>>> ---
>>>   drivers/mtd/spi-nor/Kconfig         |   7 +
>>>   drivers/mtd/spi-nor/Makefile        |   1 +
>>>   drivers/mtd/spi-nor/stm32-quadspi.c | 679
>>> ++++++++++++++++++++++++++++++++++++
>>>   3 files changed, 687 insertions(+)
>>>   create mode 100644 drivers/mtd/spi-nor/stm32-quadspi.c
>> [...]
>>
>>> +struct stm32_qspi_cmd {
>>> +    struct {
>>> +        u32 addr_width:8;
>>> +        u32 dummy:8;
>>> +        u32 data:1;
>>> +    } conf;
>> This could all be u8 ? Why this awful construct ?
> yes I could replace each u32 by u8

Yeah, please do .

>>> +    u8 opcode;
>>> +    u32 framemode;
>>> +    u32 qspimode;
>>> +    u32 addr;
>>> +    size_t len;
>>> +    void *buf;
>>> +};
>>> +
>>> +static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi)
>>> +{
>>> +    u32 cr;
>>> +    int err = 0;
>> Can readl_poll_timeout() or somesuch replace this function ?
> in fact stm32_qspi_wait_cmd test if the transfer has been complete (TCF
> flag)
> else initialize an interrupt completion.
> like the time may be long I prefer keep the interrupt wait, if you agree.

I don't really mind if it fits the hardware better and I agree with you
it does here.

>>> +    if (readl_relaxed(qspi->io_base + QUADSPI_SR) & SR_TCF)
>>> +        return 0;
>>> +
>>> +    reinit_completion(&qspi->cmd_completion);
>>> +    cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
>>> +    writel_relaxed(cr | CR_TCIE, qspi->io_base + QUADSPI_CR);
>>> +
>>> +    if
>>> (!wait_for_completion_interruptible_timeout(&qspi->cmd_completion,
>>> +                               msecs_to_jiffies(1000)))
>>> +        err = -ETIMEDOUT;
>>> +
>>> +    writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
>>> +    return err;
>>> +}
>>> +
>>> +static int stm32_qspi_wait_nobusy(struct stm32_qspi *qspi)
>>> +{
>>> +    u32 sr;
>>> +
>>> +    return readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR, sr,
>>> +                      !(sr & SR_BUSY), 10, 100000);
>>> +}
>>> +
>>> +static void stm32_qspi_set_framemode(struct spi_nor *nor,
>>> +                     struct stm32_qspi_cmd *cmd, bool read)
>>> +{
>>> +    u32 dmode = CCR_DMODE_1;
>>> +
>>> +    cmd->framemode = CCR_IMODE_1;
>>> +
>>> +    if (read) {
>>> +        switch (nor->flash_read) {
>>> +        case SPI_NOR_NORMAL:
>>> +        case SPI_NOR_FAST:
>>> +            dmode = CCR_DMODE_1;
>>> +            break;
>>> +        case SPI_NOR_DUAL:
>>> +            dmode = CCR_DMODE_2;
>>> +            break;
>>> +        case SPI_NOR_QUAD:
>>> +            dmode = CCR_DMODE_4;
>>> +            break;
>>> +        }
>>> +    }
>>> +
>>> +    cmd->framemode |= cmd->conf.data ? dmode : 0;
>>> +    cmd->framemode |= cmd->conf.addr_width ? CCR_ADMODE_1 : 0;
>>> +}
>>> +
>>> +static void stm32_qspi_read_fifo(u8 *val, void __iomem *addr)
>>> +{
>>> +    *val = readb_relaxed(addr);
>>> +}
>>> +
>>> +static void stm32_qspi_write_fifo(u8 *val, void __iomem *addr)
>>> +{
>>> +    writeb_relaxed(*val, addr);
>>> +}
>>> +
>>> +static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
>>> +                  const struct stm32_qspi_cmd *cmd)
>>> +{
>>> +    void (*tx_fifo)(u8 *, void __iomem *);
>>> +    u32 len = cmd->len, sr;
>>> +    u8 *buf = cmd->buf;
>>> +    int ret;
>>> +
>>> +    if (cmd->qspimode == CCR_FMODE_INDW)
>>> +        tx_fifo = stm32_qspi_write_fifo;
>>> +    else
>>> +        tx_fifo = stm32_qspi_read_fifo;
>>> +
>>> +    while (len--) {
>>> +        ret = readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR,
>>> +                         sr, (sr & SR_FTF),
>>> +                         10, 30000);
>> Add macros for those ad-hoc timeouts.
> I will add 2 defines (for stm32_qspi_wait_nobusy, stm32_qspi_tx_poll)
> #define STM32_QSPI_FIFO_TIMEOUT_US 30000
> #define STM32_QSPI_BUSY_TIMEOUT_US 100000

Super

>>> +        if (ret) {
>>> +            dev_err(qspi->dev, "fifo timeout (stat:%#x)\n", sr);
>>> +            break;
>>> +        }
>>> +        tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
>>> +    }
>>> +
>>> +    return ret;
>>> +}
>>
>> [...]
>>
>>> +static int stm32_qspi_send(struct stm32_qspi_flash *flash,
>>> +               const struct stm32_qspi_cmd *cmd)
>>> +{
>>> +    struct stm32_qspi *qspi = flash->qspi;
>>> +    u32 ccr, dcr, cr;
>>> +    int err;
>>> +
>>> +    err = stm32_qspi_wait_nobusy(qspi);
>>> +    if (err)
>>> +        goto abort;
>>> +
>>> +    dcr = readl_relaxed(qspi->io_base + QUADSPI_DCR) & ~DCR_FSIZE_MASK;
>>> +    dcr |= DCR_FSIZE(flash->fsize);
>>> +    writel_relaxed(dcr, qspi->io_base + QUADSPI_DCR);
>>> +
>>> +    cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
>>> +    cr &= ~CR_PRESC_MASK & ~CR_FSEL;
>>> +    cr |= CR_PRESC(flash->presc);
>>> +    cr |= flash->cs ? CR_FSEL : 0;
>>> +    writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
>>> +
>>> +    if (cmd->conf.data)
>>> +        writel_relaxed(cmd->len - 1, qspi->io_base + QUADSPI_DLR);
>>> +
>>> +    ccr = cmd->framemode | cmd->qspimode;
>>> +
>>> +    if (cmd->conf.dummy)
>>> +        ccr |= CCR_DCYC(cmd->conf.dummy);
>>> +
>>> +    if (cmd->conf.addr_width)
>>> +        ccr |= CCR_ADSIZE(cmd->conf.addr_width - 1);
>>> +
>>> +    ccr |= CCR_INST(cmd->opcode);
>>> +    writel_relaxed(ccr, qspi->io_base + QUADSPI_CCR);
>>> +
>>> +    if (cmd->conf.addr_width && cmd->qspimode != CCR_FMODE_MM)
>>> +        writel_relaxed(cmd->addr, qspi->io_base + QUADSPI_AR);
>>> +
>>> +    err = stm32_qspi_tx(qspi, cmd);
>>> +    if (err)
>>> +        goto abort;
>>> +
>>> +    if (cmd->qspimode != CCR_FMODE_MM) {
>>> +        err = stm32_qspi_wait_cmd(qspi);
>>> +        if (err)
>>> +            goto abort;
>>> +        writel_relaxed(FCR_CTCF, qspi->io_base + QUADSPI_FCR);
>>> +    }
>>> +
>>> +    return err;
>>> +
>>> +abort:
>>> +    writel_relaxed(readl_relaxed(qspi->io_base + QUADSPI_CR)
>>> +               | CR_ABORT, qspi->io_base + QUADSPI_CR);
>> Use a helper variable here too.
> ok
>>> +    dev_err(qspi->dev, "%s abort err:%d\n", __func__, err);
>>> +    return err;
>>> +}
>> [...]
>>
>>> +static int stm32_qspi_flash_setup(struct stm32_qspi *qspi,
>>> +                  struct device_node *np)
>>> +{
>>> +    u32 width, flash_read, presc, cs_num, max_rate = 0;
>>> +    struct stm32_qspi_flash *flash;
>>> +    struct mtd_info *mtd;
>>> +    int ret;
>>> +
>>> +    of_property_read_u32(np, "reg", &cs_num);
>>> +    if (cs_num >= STM32_MAX_NORCHIP)
>>> +        return -EINVAL;
>>> +
>>> +    of_property_read_u32(np, "spi-max-frequency", &max_rate);
>>> +    if (!max_rate)
>>> +        return -EINVAL;
>>> +
>>> +    presc = DIV_ROUND_UP(qspi->clk_rate, max_rate) - 1;
>>> +
>>> +    if (of_property_read_u32(np, "spi-rx-bus-width", &width))
>>> +        width = 1;
>>> +
>>> +    if (width == 4)
>>> +        flash_read = SPI_NOR_QUAD;
>>> +    else if (width == 2)
>>> +        flash_read = SPI_NOR_DUAL;
>>> +    else if (width == 1)
>>> +        flash_read = SPI_NOR_NORMAL;
>>> +    else
>>> +        return -EINVAL;
>>> +
>>> +    flash = &qspi->flash[cs_num];
>>> +    flash->qspi = qspi;
>>> +    flash->cs = cs_num;
>>> +    flash->presc = presc;
>>> +
>>> +    flash->nor.dev = qspi->dev;
>>> +    spi_nor_set_flash_node(&flash->nor, np);
>>> +    flash->nor.priv = flash;
>>> +    mtd = &flash->nor.mtd;
>>> +    mtd->priv = &flash->nor;
>>> +
>>> +    flash->nor.read = stm32_qspi_read;
>>> +    flash->nor.write = stm32_qspi_write;
>>> +    flash->nor.erase = stm32_qspi_erase;
>>> +    flash->nor.read_reg = stm32_qspi_read_reg;
>>> +    flash->nor.write_reg = stm32_qspi_write_reg;
>>> +    flash->nor.prepare = stm32_qspi_prep;
>>> +    flash->nor.unprepare = stm32_qspi_unprep;
>>> +
>>> +    writel_relaxed(LPTR_DFT_TIMEOUT, qspi->io_base + QUADSPI_LPTR);
>>> +
>>> +    writel_relaxed(CR_PRESC(presc) | CR_FTHRES(3) | CR_TCEN | CR_SSHIFT
>>> +               | CR_EN, qspi->io_base + QUADSPI_CR);
>>> +
>>> +    /* a minimum fsize must be set to sent the command id */
>>> +    flash->fsize = 25;
>> I don't understand why this is needed and the comment doesn't make
>> sense. Please fix.
> fsize field defines the size of external memory.

What external memory ? Unclear

> Normaly, this field is used only for memory map mode,
> but in fact is check in indirect mode.
> So while flash scan "spi_nor_scan":
> -I can't let 0.
> -I not know yet the size of flash.
> So I fix a temporary value
> 
> I will update my comment

Please do, also please consider that I'm reading the comment and I
barely have any clue about this hardware , so make sure I can understand it.

>>> +    ret = spi_nor_scan(&flash->nor, NULL, flash_read);
>>> +    if (ret) {
>>> +        dev_err(qspi->dev, "device scan failed\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    flash->fsize = __fls(mtd->size) - 1;
>>> +
>>> +    writel_relaxed(DCR_CSHT(1), qspi->io_base + QUADSPI_DCR);
>>> +
>>> +    ret = mtd_device_register(mtd, NULL, 0);
>>> +    if (ret) {
>>> +        dev_err(qspi->dev, "mtd device parse failed\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    dev_dbg(qspi->dev, "read mm:%s cs:%d bus:%d\n",
>>> +        qspi->read_mode == CCR_FMODE_MM ? "yes" : "no", cs_num, width);
>>> +
>>> +    return 0;
>>> +}
>> [...]
>>
> 


-- 
Best regards,
Marek Vasut
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Re: [PATCH 2/2] mtd: spi-nor: add driver for STM32 quad spi flash controller

[Ludovic BARRE]

On 03/29/2017 03:09 PM, Marek Vasut wrote:
> On 03/29/2017 02:24 PM, Ludovic BARRE wrote:
>> hi Marek
> Hi!
>
>> thanks for review
>> comment below
>>
>> On 03/29/2017 12:54 PM, Marek Vasut wrote:
>>> On 03/27/2017 02:54 PM, Ludovic Barre wrote:
>>>> From: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
>>>>
>>>> The quadspi is a specialized communication interface targeting single,
>>>> dual or quad SPI Flash memories.
>>>>
>>>> It can operate in any of the following modes:
>>>> -indirect mode: all the operations are performed using the quadspi
>>>>    registers
>>>> -read memory-mapped mode: the external Flash memory is mapped to the
>>>>    microcontroller address space and is seen by the system as if it was
>>>>    an internal memory
>>>>
>>>> Signed-off-by: Ludovic Barre <ludovic.barre-qxv4g6HH51o@public.gmane.org>
>>> Hi! I presume this is not compatible with the Cadence QSPI or any other
>>> QSPI controller, huh ?
>> it's not a cadence QSPI, it's specific for stm32 platform
> OK, got it. Didn't ST use Cadence IP somewhere too though ?
> That's probably what confused me, oh well ...
>
>>> Mostly minor nits below ...
>>>
>>>> ---
>>>>    drivers/mtd/spi-nor/Kconfig         |   7 +
>>>>    drivers/mtd/spi-nor/Makefile        |   1 +
>>>>    drivers/mtd/spi-nor/stm32-quadspi.c | 679
>>>> ++++++++++++++++++++++++++++++++++++
>>>>    3 files changed, 687 insertions(+)
>>>>    create mode 100644 drivers/mtd/spi-nor/stm32-quadspi.c
>>> [...]
>>>
>>>> +struct stm32_qspi_cmd {
>>>> +    struct {
>>>> +        u32 addr_width:8;
>>>> +        u32 dummy:8;
>>>> +        u32 data:1;
>>>> +    } conf;
>>> This could all be u8 ? Why this awful construct ?
>> yes I could replace each u32 by u8
> Yeah, please do .
>
>>>> +    u8 opcode;
>>>> +    u32 framemode;
>>>> +    u32 qspimode;
>>>> +    u32 addr;
>>>> +    size_t len;
>>>> +    void *buf;
>>>> +};
>>>> +
>>>> +static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi)
>>>> +{
>>>> +    u32 cr;
>>>> +    int err = 0;
>>> Can readl_poll_timeout() or somesuch replace this function ?
>> in fact stm32_qspi_wait_cmd test if the transfer has been complete (TCF
>> flag)
>> else initialize an interrupt completion.
>> like the time may be long I prefer keep the interrupt wait, if you agree.
> I don't really mind if it fits the hardware better and I agree with you
> it does here.
>
>>>> +    if (readl_relaxed(qspi->io_base + QUADSPI_SR) & SR_TCF)
>>>> +        return 0;
>>>> +
>>>> +    reinit_completion(&qspi->cmd_completion);
>>>> +    cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
>>>> +    writel_relaxed(cr | CR_TCIE, qspi->io_base + QUADSPI_CR);
>>>> +
>>>> +    if
>>>> (!wait_for_completion_interruptible_timeout(&qspi->cmd_completion,
>>>> +                               msecs_to_jiffies(1000)))
>>>> +        err = -ETIMEDOUT;
>>>> +
>>>> +    writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
>>>> +    return err;
>>>> +}
>>>> +
>>>> +static int stm32_qspi_wait_nobusy(struct stm32_qspi *qspi)
>>>> +{
>>>> +    u32 sr;
>>>> +
>>>> +    return readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR, sr,
>>>> +                      !(sr & SR_BUSY), 10, 100000);
>>>> +}
>>>> +
>>>> +static void stm32_qspi_set_framemode(struct spi_nor *nor,
>>>> +                     struct stm32_qspi_cmd *cmd, bool read)
>>>> +{
>>>> +    u32 dmode = CCR_DMODE_1;
>>>> +
>>>> +    cmd->framemode = CCR_IMODE_1;
>>>> +
>>>> +    if (read) {
>>>> +        switch (nor->flash_read) {
>>>> +        case SPI_NOR_NORMAL:
>>>> +        case SPI_NOR_FAST:
>>>> +            dmode = CCR_DMODE_1;
>>>> +            break;
>>>> +        case SPI_NOR_DUAL:
>>>> +            dmode = CCR_DMODE_2;
>>>> +            break;
>>>> +        case SPI_NOR_QUAD:
>>>> +            dmode = CCR_DMODE_4;
>>>> +            break;
>>>> +        }
>>>> +    }
>>>> +
>>>> +    cmd->framemode |= cmd->conf.data ? dmode : 0;
>>>> +    cmd->framemode |= cmd->conf.addr_width ? CCR_ADMODE_1 : 0;
>>>> +}
>>>> +
>>>> +static void stm32_qspi_read_fifo(u8 *val, void __iomem *addr)
>>>> +{
>>>> +    *val = readb_relaxed(addr);
>>>> +}
>>>> +
>>>> +static void stm32_qspi_write_fifo(u8 *val, void __iomem *addr)
>>>> +{
>>>> +    writeb_relaxed(*val, addr);
>>>> +}
>>>> +
>>>> +static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
>>>> +                  const struct stm32_qspi_cmd *cmd)
>>>> +{
>>>> +    void (*tx_fifo)(u8 *, void __iomem *);
>>>> +    u32 len = cmd->len, sr;
>>>> +    u8 *buf = cmd->buf;
>>>> +    int ret;
>>>> +
>>>> +    if (cmd->qspimode == CCR_FMODE_INDW)
>>>> +        tx_fifo = stm32_qspi_write_fifo;
>>>> +    else
>>>> +        tx_fifo = stm32_qspi_read_fifo;
>>>> +
>>>> +    while (len--) {
>>>> +        ret = readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR,
>>>> +                         sr, (sr & SR_FTF),
>>>> +                         10, 30000);
>>> Add macros for those ad-hoc timeouts.
>> I will add 2 defines (for stm32_qspi_wait_nobusy, stm32_qspi_tx_poll)
>> #define STM32_QSPI_FIFO_TIMEOUT_US 30000
>> #define STM32_QSPI_BUSY_TIMEOUT_US 100000
> Super
>
>>>> +        if (ret) {
>>>> +            dev_err(qspi->dev, "fifo timeout (stat:%#x)\n", sr);
>>>> +            break;
>>>> +        }
>>>> +        tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
>>>> +    }
>>>> +
>>>> +    return ret;
>>>> +}
>>> [...]
>>>
>>>> +static int stm32_qspi_send(struct stm32_qspi_flash *flash,
>>>> +               const struct stm32_qspi_cmd *cmd)
>>>> +{
>>>> +    struct stm32_qspi *qspi = flash->qspi;
>>>> +    u32 ccr, dcr, cr;
>>>> +    int err;
>>>> +
>>>> +    err = stm32_qspi_wait_nobusy(qspi);
>>>> +    if (err)
>>>> +        goto abort;
>>>> +
>>>> +    dcr = readl_relaxed(qspi->io_base + QUADSPI_DCR) & ~DCR_FSIZE_MASK;
>>>> +    dcr |= DCR_FSIZE(flash->fsize);
>>>> +    writel_relaxed(dcr, qspi->io_base + QUADSPI_DCR);
>>>> +
>>>> +    cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
>>>> +    cr &= ~CR_PRESC_MASK & ~CR_FSEL;
>>>> +    cr |= CR_PRESC(flash->presc);
>>>> +    cr |= flash->cs ? CR_FSEL : 0;
>>>> +    writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
>>>> +
>>>> +    if (cmd->conf.data)
>>>> +        writel_relaxed(cmd->len - 1, qspi->io_base + QUADSPI_DLR);
>>>> +
>>>> +    ccr = cmd->framemode | cmd->qspimode;
>>>> +
>>>> +    if (cmd->conf.dummy)
>>>> +        ccr |= CCR_DCYC(cmd->conf.dummy);
>>>> +
>>>> +    if (cmd->conf.addr_width)
>>>> +        ccr |= CCR_ADSIZE(cmd->conf.addr_width - 1);
>>>> +
>>>> +    ccr |= CCR_INST(cmd->opcode);
>>>> +    writel_relaxed(ccr, qspi->io_base + QUADSPI_CCR);
>>>> +
>>>> +    if (cmd->conf.addr_width && cmd->qspimode != CCR_FMODE_MM)
>>>> +        writel_relaxed(cmd->addr, qspi->io_base + QUADSPI_AR);
>>>> +
>>>> +    err = stm32_qspi_tx(qspi, cmd);
>>>> +    if (err)
>>>> +        goto abort;
>>>> +
>>>> +    if (cmd->qspimode != CCR_FMODE_MM) {
>>>> +        err = stm32_qspi_wait_cmd(qspi);
>>>> +        if (err)
>>>> +            goto abort;
>>>> +        writel_relaxed(FCR_CTCF, qspi->io_base + QUADSPI_FCR);
>>>> +    }
>>>> +
>>>> +    return err;
>>>> +
>>>> +abort:
>>>> +    writel_relaxed(readl_relaxed(qspi->io_base + QUADSPI_CR)
>>>> +               | CR_ABORT, qspi->io_base + QUADSPI_CR);
>>> Use a helper variable here too.
>> ok
>>>> +    dev_err(qspi->dev, "%s abort err:%d\n", __func__, err);
>>>> +    return err;
>>>> +}
>>> [...]
>>>
>>>> +static int stm32_qspi_flash_setup(struct stm32_qspi *qspi,
>>>> +                  struct device_node *np)
>>>> +{
>>>> +    u32 width, flash_read, presc, cs_num, max_rate = 0;
>>>> +    struct stm32_qspi_flash *flash;
>>>> +    struct mtd_info *mtd;
>>>> +    int ret;
>>>> +
>>>> +    of_property_read_u32(np, "reg", &cs_num);
>>>> +    if (cs_num >= STM32_MAX_NORCHIP)
>>>> +        return -EINVAL;
>>>> +
>>>> +    of_property_read_u32(np, "spi-max-frequency", &max_rate);
>>>> +    if (!max_rate)
>>>> +        return -EINVAL;
>>>> +
>>>> +    presc = DIV_ROUND_UP(qspi->clk_rate, max_rate) - 1;
>>>> +
>>>> +    if (of_property_read_u32(np, "spi-rx-bus-width", &width))
>>>> +        width = 1;
>>>> +
>>>> +    if (width == 4)
>>>> +        flash_read = SPI_NOR_QUAD;
>>>> +    else if (width == 2)
>>>> +        flash_read = SPI_NOR_DUAL;
>>>> +    else if (width == 1)
>>>> +        flash_read = SPI_NOR_NORMAL;
>>>> +    else
>>>> +        return -EINVAL;
>>>> +
>>>> +    flash = &qspi->flash[cs_num];
>>>> +    flash->qspi = qspi;
>>>> +    flash->cs = cs_num;
>>>> +    flash->presc = presc;
>>>> +
>>>> +    flash->nor.dev = qspi->dev;
>>>> +    spi_nor_set_flash_node(&flash->nor, np);
>>>> +    flash->nor.priv = flash;
>>>> +    mtd = &flash->nor.mtd;
>>>> +    mtd->priv = &flash->nor;
>>>> +
>>>> +    flash->nor.read = stm32_qspi_read;
>>>> +    flash->nor.write = stm32_qspi_write;
>>>> +    flash->nor.erase = stm32_qspi_erase;
>>>> +    flash->nor.read_reg = stm32_qspi_read_reg;
>>>> +    flash->nor.write_reg = stm32_qspi_write_reg;
>>>> +    flash->nor.prepare = stm32_qspi_prep;
>>>> +    flash->nor.unprepare = stm32_qspi_unprep;
>>>> +
>>>> +    writel_relaxed(LPTR_DFT_TIMEOUT, qspi->io_base + QUADSPI_LPTR);
>>>> +
>>>> +    writel_relaxed(CR_PRESC(presc) | CR_FTHRES(3) | CR_TCEN | CR_SSHIFT
>>>> +               | CR_EN, qspi->io_base + QUADSPI_CR);
>>>> +
>>>> +    /* a minimum fsize must be set to sent the command id */
>>>> +    flash->fsize = 25;
>>> I don't understand why this is needed and the comment doesn't make
>>> sense. Please fix.
>> fsize field defines the size of external memory.
> What external memory ? Unclear
oops, fsize field defined the size of "flash memory" in stm32 qspi 
controller.
Number of bytes in Flash memory = 2 ^[FSIZE+1].
To sent a nor cmd this field must be set (hardware issue),
but before "spi_nor_scan" the size of flash nor is not know.
So I set a temporary value (workaround).

After "spi_nor_scan" the fsize is overwritten by the right value
flash->fsize = __fls(mtd->size) - 1;
>> Normaly, this field is used only for memory map mode,
>> but in fact is check in indirect mode.
>> So while flash scan "spi_nor_scan":
>> -I can't let 0.
>> -I not know yet the size of flash.
>> So I fix a temporary value
>>
>> I will update my comment
> Please do, also please consider that I'm reading the comment and I
> barely have any clue about this hardware , so make sure I can understand it.
>
>>>> +    ret = spi_nor_scan(&flash->nor, NULL, flash_read);
>>>> +    if (ret) {
>>>> +        dev_err(qspi->dev, "device scan failed\n");
>>>> +        return ret;
>>>> +    }
>>>> +
>>>> +    flash->fsize = __fls(mtd->size) - 1;
>>>> +
>>>> +    writel_relaxed(DCR_CSHT(1), qspi->io_base + QUADSPI_DCR);
>>>> +
>>>> +    ret = mtd_device_register(mtd, NULL, 0);
>>>> +    if (ret) {
>>>> +        dev_err(qspi->dev, "mtd device parse failed\n");
>>>> +        return ret;
>>>> +    }
>>>> +
>>>> +    dev_dbg(qspi->dev, "read mm:%s cs:%d bus:%d\n",
>>>> +        qspi->read_mode == CCR_FMODE_MM ? "yes" : "no", cs_num, width);
>>>> +
>>>> +    return 0;
>>>> +}
>>> [...]
>>>
>

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Re: [PATCH 2/2] mtd: spi-nor: add driver for STM32 quad spi flash controller

[Marek Vasut]

On 03/29/2017 03:35 PM, Ludovic BARRE wrote:

[...]

>>>>> +    writel_relaxed(CR_PRESC(presc) | CR_FTHRES(3) | CR_TCEN |
>>>>> CR_SSHIFT
>>>>> +               | CR_EN, qspi->io_base + QUADSPI_CR);
>>>>> +
>>>>> +    /* a minimum fsize must be set to sent the command id */
>>>>> +    flash->fsize = 25;
>>>> I don't understand why this is needed and the comment doesn't make
>>>> sense. Please fix.
>>> fsize field defines the size of external memory.
>> What external memory ? Unclear
> oops, fsize field defined the size of "flash memory" in stm32 qspi
> controller.

Errr, now I am totally lost :) Is that some internal SPI NOR ? Shouldn't
the size be coming from DT or something ?

> Number of bytes in Flash memory = 2 ^[FSIZE+1].
> To sent a nor cmd this field must be set (hardware issue),
> but before "spi_nor_scan" the size of flash nor is not know.
> So I set a temporary value (workaround).

Is it needed before the scan ?

> After "spi_nor_scan" the fsize is overwritten by the right value
> flash->fsize = __fls(mtd->size) - 1;
>>> Normaly, this field is used only for memory map mode,
>>> but in fact is check in indirect mode.
>>> So while flash scan "spi_nor_scan":
>>> -I can't let 0.
>>> -I not know yet the size of flash.
>>> So I fix a temporary value
>>>
>>> I will update my comment
>> Please do, also please consider that I'm reading the comment and I
>> barely have any clue about this hardware , so make sure I can
>> understand it.
>>
>>>>> +    ret = spi_nor_scan(&flash->nor, NULL, flash_read);
>>>>> +    if (ret) {
>>>>> +        dev_err(qspi->dev, "device scan failed\n");
>>>>> +        return ret;
>>>>> +    }
>>>>> +
>>>>> +    flash->fsize = __fls(mtd->size) - 1;
>>>>> +
>>>>> +    writel_relaxed(DCR_CSHT(1), qspi->io_base + QUADSPI_DCR);
>>>>> +
>>>>> +    ret = mtd_device_register(mtd, NULL, 0);
>>>>> +    if (ret) {
>>>>> +        dev_err(qspi->dev, "mtd device parse failed\n");
>>>>> +        return ret;
>>>>> +    }
>>>>> +
>>>>> +    dev_dbg(qspi->dev, "read mm:%s cs:%d bus:%d\n",
>>>>> +        qspi->read_mode == CCR_FMODE_MM ? "yes" : "no", cs_num,
>>>>> width);
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>> [...]
>>>>
>>
> 


-- 
Best regards,
Marek Vasut

Re: [PATCH 2/2] mtd: spi-nor: add driver for STM32 quad spi flash controller

[Ludovic BARRE]

On 03/29/2017 03:57 PM, Marek Vasut wrote:
> On 03/29/2017 03:35 PM, Ludovic BARRE wrote:
>
> [...]
>
>>>>>> +    writel_relaxed(CR_PRESC(presc) | CR_FTHRES(3) | CR_TCEN |
>>>>>> CR_SSHIFT
>>>>>> +               | CR_EN, qspi->io_base + QUADSPI_CR);
>>>>>> +
>>>>>> +    /* a minimum fsize must be set to sent the command id */
>>>>>> +    flash->fsize = 25;
>>>>> I don't understand why this is needed and the comment doesn't make
>>>>> sense. Please fix.
>>>> fsize field defines the size of external memory.
>>> What external memory ? Unclear
>> oops, fsize field defined the size of "flash memory" in stm32 qspi
>> controller.
> Errr, now I am totally lost :) Is that some internal SPI NOR ? Shouldn't
> the size be coming from DT or something ?
>
>> Number of bytes in Flash memory = 2 ^[FSIZE+1].
>> To sent a nor cmd this field must be set (hardware issue),
>> but before "spi_nor_scan" the size of flash nor is not know.
>> So I set a temporary value (workaround).
> Is it needed before the scan ?
yes it's needed before scan (fix a "stm32 qspi controller" issue)

sorry, I try to reformulate:

The nor flash (external component like micron n25q128a13
or spansion s25fl512s ...) is connected to stm32 by classic
spi-nor interface cs, clock and 1/2/4 IO lines.

the stm32 microprocessor has a dedicated controller to
manage spi-nor interface, it's stm32 qspi.

In stm32 qspi controller there is a register with fsize field
which define the size of nor flash (n25q128a13 or s25fl512s...).

fsize can't be null, else the stm32 qspi controller doesn't send
spi-nor command. it's "stm32 qspi controller" issue.

Before the "spi_nor_scan" the size of nor flash (n25q128a13
or s25fl512s...) is not know. So we set a temporary value just
to discover the nor flash with "spi_nor_scan". After we can
set the right value (mtd->size) in fsize.
>> After "spi_nor_scan" the fsize is overwritten by the right value
>> flash->fsize = __fls(mtd->size) - 1;
>>>> Normaly, this field is used only for memory map mode,
>>>> but in fact is check in indirect mode.
>>>> So while flash scan "spi_nor_scan":
>>>> -I can't let 0.
>>>> -I not know yet the size of flash.
>>>> So I fix a temporary value
>>>>
>>>> I will update my comment
>>> Please do, also please consider that I'm reading the comment and I
>>> barely have any clue about this hardware , so make sure I can
>>> understand it.
>>>
>>>>>> +    ret = spi_nor_scan(&flash->nor, NULL, flash_read);
>>>>>> +    if (ret) {
>>>>>> +        dev_err(qspi->dev, "device scan failed\n");
>>>>>> +        return ret;
>>>>>> +    }
>>>>>> +
>>>>>> +    flash->fsize = __fls(mtd->size) - 1;
>>>>>> +
>>>>>> +    writel_relaxed(DCR_CSHT(1), qspi->io_base + QUADSPI_DCR);
>>>>>> +
>>>>>> +    ret = mtd_device_register(mtd, NULL, 0);
>>>>>> +    if (ret) {
>>>>>> +        dev_err(qspi->dev, "mtd device parse failed\n");
>>>>>> +        return ret;
>>>>>> +    }
>>>>>> +
>>>>>> +    dev_dbg(qspi->dev, "read mm:%s cs:%d bus:%d\n",
>>>>>> +        qspi->read_mode == CCR_FMODE_MM ? "yes" : "no", cs_num,
>>>>>> width);
>>>>>> +
>>>>>> +    return 0;
>>>>>> +}
>>>>> [...]
>>>>>
>

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Re: [PATCH 2/2] mtd: spi-nor: add driver for STM32 quad spi flash controller

[Marek Vasut]

On 03/29/2017 06:38 PM, Ludovic BARRE wrote:
> 
> 
> On 03/29/2017 03:57 PM, Marek Vasut wrote:
>> On 03/29/2017 03:35 PM, Ludovic BARRE wrote:
>>
>> [...]
>>
>>>>>>> +    writel_relaxed(CR_PRESC(presc) | CR_FTHRES(3) | CR_TCEN |
>>>>>>> CR_SSHIFT
>>>>>>> +               | CR_EN, qspi->io_base + QUADSPI_CR);
>>>>>>> +
>>>>>>> +    /* a minimum fsize must be set to sent the command id */
>>>>>>> +    flash->fsize = 25;
>>>>>> I don't understand why this is needed and the comment doesn't make
>>>>>> sense. Please fix.
>>>>> fsize field defines the size of external memory.
>>>> What external memory ? Unclear
>>> oops, fsize field defined the size of "flash memory" in stm32 qspi
>>> controller.
>> Errr, now I am totally lost :) Is that some internal SPI NOR ? Shouldn't
>> the size be coming from DT or something ?
>>
>>> Number of bytes in Flash memory = 2 ^[FSIZE+1].
>>> To sent a nor cmd this field must be set (hardware issue),
>>> but before "spi_nor_scan" the size of flash nor is not know.
>>> So I set a temporary value (workaround).
>> Is it needed before the scan ?
> yes it's needed before scan (fix a "stm32 qspi controller" issue)
> 
> sorry, I try to reformulate:
> 
> The nor flash (external component like micron n25q128a13
> or spansion s25fl512s ...) is connected to stm32 by classic
> spi-nor interface cs, clock and 1/2/4 IO lines.
> 
> the stm32 microprocessor has a dedicated controller to
> manage spi-nor interface, it's stm32 qspi.
> 
> In stm32 qspi controller there is a register with fsize field
> which define the size of nor flash (n25q128a13 or s25fl512s...).
> 
> fsize can't be null, else the stm32 qspi controller doesn't send
> spi-nor command. it's "stm32 qspi controller" issue.
> 
> Before the "spi_nor_scan" the size of nor flash (n25q128a13
> or s25fl512s...) is not know. So we set a temporary value just
> to discover the nor flash with "spi_nor_scan". After we can
> set the right value (mtd->size) in fsize.

I see, now it makes sense. Such a beefy comment would be nice :)

-- 
Best regards,
Marek Vasut

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