mtd: aspeed: add memory controllers for the Aspeed AST2400 SoC

This driver adds mtd support for the Aspeed AST2400 SoC static memory
controllers:

 * New Static Memory Controller (referred as FMC)
   . BMC firmware
   . AST2500 compatible register set
   . 5 chip select pins (CE0 ∼ CE4)
   . supports NOR flash, NAND flash and SPI flash memory.

 * SPI Flash Controller (SPI)
   . host Firmware
   . slightly different register set, between AST2500 and the legacy
     controller
   . supports SPI flash memory
   . 1 chip select pin (CE0)

The legacy static memory controller (referred as SMC) is not
supported, as well as types other than SPI.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>

drivers/mtd/spi-nor/Kconfig

@@ -35,7 +35,7 @@ config SPI_ASPEED_SMC
 	depends on HAS_IOMEM && OF
 	help
 	  This enables support for the Firmware Memory controller (FMC)
-	  in the Aspeed AST2500 SoC when attached to SPI NOR chips,
+	  in the Aspeed AST2500/AST2400 SoCs when attached to SPI NOR chips,
 	  and support for the SPI flash memory controller (SPI) for
 	  the host firmware. The implementation only supports SPI NOR.
 

drivers/mtd/spi-nor/aspeed-smc.c

@@ -44,8 +44,27 @@ struct aspeed_smc_info {
 	void (*set_4b)(struct aspeed_smc_chip *chip);
 };
 
+static void aspeed_smc_chip_set_4b_spi_2400(struct aspeed_smc_chip *chip);
 static void aspeed_smc_chip_set_4b(struct aspeed_smc_chip *chip);
 
+static const struct aspeed_smc_info fmc_2400_info = {
+	.maxsize = 64 * 1024 * 1024,
+	.nce = 5,
+	.hastype = true,
+	.we0 = 16,
+	.ctl0 = 0x10,
+	.set_4b = aspeed_smc_chip_set_4b,
+};
+
+static const struct aspeed_smc_info spi_2400_info = {
+	.maxsize = 64 * 1024 * 1024,
+	.nce = 1,
+	.hastype = false,
+	.we0 = 0,
+	.ctl0 = 0x04,
+	.set_4b = aspeed_smc_chip_set_4b_spi_2400,
+};
+
 static const struct aspeed_smc_info fmc_2500_info = {
 	.maxsize = 256 * 1024 * 1024,
 	.nce = 3,
@@ -135,6 +154,7 @@ struct aspeed_smc_controller {
 #define CONTROL_IO_DUMMY_HI		BIT(14)
 #define CONTROL_IO_DUMMY_HI_SHIFT	14
 #define CONTROL_CLK_DIV4		BIT(13) /* others */
+#define CONTROL_IO_ADDRESS_4B		BIT(13) /* AST2400 SPI */
 #define CONTROL_RW_MERGE		BIT(12)
 #define CONTROL_IO_DUMMY_LO_SHIFT	6
 #define CONTROL_IO_DUMMY_LO		GENMASK(7, \
@@ -397,6 +417,8 @@ static int aspeed_smc_remove(struct platform_device *dev)
 }
 
 static const struct of_device_id aspeed_smc_matches[] = {
+	{ .compatible = "aspeed,ast2400-fmc", .data = &fmc_2400_info },
+	{ .compatible = "aspeed,ast2400-spi", .data = &spi_2400_info },
 	{ .compatible = "aspeed,ast2500-fmc", .data = &fmc_2500_info },
 	{ .compatible = "aspeed,ast2500-spi", .data = &spi_2500_info },
 	{ }
@@ -470,6 +492,17 @@ static void aspeed_smc_chip_set_4b(struct aspeed_smc_chip *chip)
 	}
 }
 
+/*
+ * The AST2400 SPI flash controller does not have a CE Control
+ * register. It uses the CE0 control register to set 4Byte mode at the
+ * controller level.
+ */
+static void aspeed_smc_chip_set_4b_spi_2400(struct aspeed_smc_chip *chip)
+{
+	chip->ctl_val[smc_base] |= CONTROL_IO_ADDRESS_4B;
+	chip->ctl_val[smc_read] |= CONTROL_IO_ADDRESS_4B;
+}
+
 static int aspeed_smc_chip_setup_init(struct aspeed_smc_chip *chip,
 				      struct resource *res)
 {