Add spi-nor driver for Realtek RTL838x/RTL839x switch SoCs

PATCH Superseded Bert Vermeulen 3 participants 6 messages Dec 15, 2020 – Dec 20, 2020

Subsystems (2)

Memory technology devices (MTD) SPI NOR

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Bert Vermeulen

author

2020-12-15 21:48 UTC #0 lore raw

PATCH 1/1 Add spi-nor driver for Realtek RTL838x/RTL839x switch SoCs

This driver supports the spiflash core in all RTL838x/RTL839x SoCs, and likely some older models as well (RTL8196C).

Signed-off-by Bert Vermeulen <[email protected]>

---
 drivers/mtd/spi-nor/controllers/Kconfig       |   7 +
 drivers/mtd/spi-nor/controllers/Makefile      |   1 +
 .../spi-nor/controllers/rtl8380-spiflash.c    | 347 ++++++++++++++++++
 .../spi-nor/controllers/rtl8380-spiflash.h    |  34 ++
 4 files changed, 389 insertions(+)
 create mode 100644 drivers/mtd/spi-nor/controllers/rtl8380-spiflash.c
 create mode 100644 drivers/mtd/spi-nor/controllers/rtl8380-spiflash.h

drivers/mtd/spi-nor/controllers/Kconfig +7 -0

index 5c0e0ec2e6d1..1e035c511ea5 100644
@@ -62,3 +62,10 @@ 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_REALTEK_RTL8380
+	tristate "Realtek RTL8380 SPI flash controller"
+	depends on MACH_REALTEK
+	help
+	  This enables support for the SPI flash controller in the Realtek
+	  RTL8380 series SoCs.

drivers/mtd/spi-nor/controllers/Makefile +1 -0

index e7abba491d98..f03a79e88a78 100644
@@ -5,3 +5,4 @@ obj-$(CONFIG_SPI_NXP_SPIFI)	+= nxp-spifi.o
 obj-$(CONFIG_SPI_INTEL_SPI)	+= intel-spi.o
 obj-$(CONFIG_SPI_INTEL_SPI_PCI)	+= intel-spi-pci.o
 obj-$(CONFIG_SPI_INTEL_SPI_PLATFORM)	+= intel-spi-platform.o
+obj-$(CONFIG_SPI_REALTEK_RTL8380)	+= rtl8380-spiflash.o

drivers/mtd/spi-nor/controllers/rtl8380-spiflash.c new file +347 -0

347 lines not on this page · raw message

drivers/mtd/spi-nor/controllers/rtl8380-spiflash.h new file +34 -0

new file mode 100644
index 000000000000..754e67087ed1
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#ifndef _RTL8380_SPIFLASH_H_
+#define _RTL8380_SPIFLASH_H_
+
+struct rtl8380_nor {
+	struct spi_nor nor;
+	void __iomem *base;
+	u32 cs;
+};
+
+/* SPI Flash Configuration Register */
+#define RTL8380_SPI_SFCR		0x00
+#define RTL8380_SPI_SFCR_RBO		BIT(28)
+#define RTL8380_SPI_SFCR_WBO		BIT(27)
+
+/* SPI Flash Control and Status Register */
+#define RTL8380_SPI_SFCSR		0x08
+#define RTL8380_SPI_SFCSR_CSB0		BIT(31)
+#define RTL8380_SPI_SFCSR_CSB1		BIT(30)
+#define RTL8380_SPI_SFCSR_RDY		BIT(27)
+#define RTL8380_SPI_SFCSR_CS		BIT(24)
+#define RTL8380_SPI_SFCSR_LEN_MASK	~(0x03 << 28)
+#define RTL8380_SPI_SFCSR_LEN1		(0x00 << 28)
+#define RTL8380_SPI_SFCSR_LEN2		(0x01 << 28)
+#define RTL8380_SPI_SFCSR_LEN3		(0x02 << 28)
+#define RTL8380_SPI_SFCSR_LEN4		(0x03 << 28)
+
+/* SPI Flash Data Registers */
+#define RTL8380_SPI_SFDR	0x0c
+#define RTL8380_SPI_SFDR2	0x10
+
+#endif /* _RTL8380_SPIFLASH_H_ */
+

Signature · 1 line

2.25.1

[email protected]

2020-12-16 08:31 UTC #1 lore raw

Quoted 3 lines · Bert Vermeulen

This driver supports the spiflash core in all RTL838x/RTL839x SoCs, and likely some older models as well (RTL8196C).

Can we use SPIMEM and move this under drivers/spi/ instead?

Cheers,
ta

Quoted 9 lines

Signed-off-by Bert Vermeulen <[email protected]>

---
 drivers/mtd/spi-nor/controllers/Kconfig       |   7 +
 drivers/mtd/spi-nor/controllers/Makefile      |   1 +
 .../spi-nor/controllers/rtl8380-spiflash.c    | 347 ++++++++++++++++++
 .../spi-nor/controllers/rtl8380-spiflash.h    |  34 ++
 4 files changed, 389 insertions(+)
 create mode 100644 drivers/mtd/spi-nor/controllers/rtl8380-spiflash.c
 create mode 100644 drivers/mtd/spi-nor/controllers/rtl8380-spiflash.h

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Chuanhong Guo

2020-12-16 11:16 UTC #2 lore raw

Hi!

Quoted 9 lines · On Wed, Dec 16, 2020 at 4:30 PM <[email protected]> wrote:

Quoted 3 lines · Bert Vermeulen
This driver supports the spiflash core in all RTL838x/RTL839x SoCs, and likely some older models as well (RTL8196C).
Can we use SPIMEM and move this under drivers/spi/ instead?
Cheers,
ta

Just took a brief look at the code, and here's my current understanding of this controller:
1. CS is controlled separately with SFCSR_CSB* bits
2. To write 1-4 bytes, set SFCSR_LEN* and write to SFDR
2. To read 1-4 bytes, set SFCSR_LEN* and read SFDR

If that's true, this is a generic half-duplex spi controller, and the driver should register a spi_controller with set_cs and transfer_one implemented.

Signature · 6 lines

Regards,
Chuanhong Guo

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http://lists.infradead.org/mailman/listinfo/linux-mtd/

Bert Vermeulen

author

2020-12-19 22:59 UTC #3 lore raw

In reply to [email protected]

Quoted 5 lines · On 12/16/20 9:30 AM, [email protected] wrote:

Quoted 3 lines · Bert Vermeulen
This driver supports the spiflash core in all RTL838x/RTL839x SoCs, and likely some older models as well (RTL8196C).
Can we use SPIMEM and move this under drivers/spi/ instead?

I wasn't aware spimem was the thing to use for new drivers. I will rewrite the driver to that API.

Signature · 2 lines

Bert Vermeulen
[email protected]

Chuanhong Guo

2020-12-20 08:52 UTC #4 lore raw

Hi!

Quoted 10 lines · Bert Vermeulen

Quoted 5 lines · On 12/16/20 9:30 AM, [email protected] wrote:
Quoted 3 lines · Bert Vermeulen
This driver supports the spiflash core in all RTL838x/RTL839x SoCs, and likely some older models as well (RTL8196C).
Can we use SPIMEM and move this under drivers/spi/ instead?
I wasn't aware spimem was the thing to use for new drivers. I will rewrite the driver to that API.

Are there any limitations preventing this from being implemented as a generic SPI controller?
spi-nor and spi-mem are designed for controllers which can only perform spi-mem/spi-nor specific transfers. I can't find such limitations from your current driver code.

BTW I found a SPI controller driver for RTL8196C here: [0] It seems pretty similar to the controller you are working on.

[0]: https://github.com/hackpascal/lede-rtl8196c/blob/realtek/target/linux/realtek/files/drivers/spi/spi-realtek.c

Signature · 2 lines

Regards,
Chuanhong Guo

Bert Vermeulen

author

2020-12-20 15:37 UTC #5 lore raw

Quoted 20 lines · Chuanhong Guo

Hi!
Quoted 10 lines · Bert Vermeulen
Quoted 5 lines · On 12/16/20 9:30 AM, [email protected] wrote:
Quoted 3 lines · Bert Vermeulen
This driver supports the spiflash core in all RTL838x/RTL839x SoCs, and likely some older models as well (RTL8196C).
Can we use SPIMEM and move this under drivers/spi/ instead?
I wasn't aware spimem was the thing to use for new drivers. I will rewrite the driver to that API.
Are there any limitations preventing this from being implemented as a generic SPI controller?
spi-nor and spi-mem are designed for controllers which can only perform spi-mem/spi-nor specific transfers. I can't find such limitations from your current driver code.

Quoted 4 lines

BTW I found a SPI controller driver for RTL8196C here: [0] It seems pretty similar to the controller you are working on.
[0]: https://github.com/hackpascal/lede-rtl8196c/blob/realtek/target/linux/realtek/files/drivers/spi/spi-realtek.c

The SoC's SPI core is very much intended for SPI flash use only, and indeed we haven't come across anything else connected to that SPI bus in dozens of devices.

I wrote my driver based on Realtek code and a datasheet for the (older) RTL8196C found floating around the net, and found no inconsistencies.

I hadn't seen that RTL8196C driver, but if it works that proves a plain SPI driver will do. I'll investigate.

Signature · 2 lines

Bert Vermeulen
[email protected]