memory: add Renesas RPC-IF driver

Add the memory driver for Renesas RPC-IF which registers either SPI or
HyperFLash device depending on the contents of the device tree subnode.
It also provides the absract "back end" device APIs that can be used by
the "front end" SPI/MTD drivers to talk to the real hardware.

Based on the original patch by Mason Yang <masonccyang@mxic.com.tw>.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Link: https://lore.kernel.org/r/9a3606ec-d4d0-c63a-4fb6-631ab38e621c@cogentembedded.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/memory/Kconfig

@@ -174,6 +174,15 @@ config PL353_SMC
 	  This driver is for the ARM PL351/PL353 Static Memory
 	  Controller(SMC) module.
 
+config RENESAS_RPCIF
+	tristate "Renesas RPC-IF driver"
+	depends on ARCH_RENESAS
+	select REGMAP_MMIO
+	help
+	  This supports Renesas R-Car Gen3 RPC-IF which provides either SPI
+	  host or HyperFlash. You'll have to select individual components
+	  under the corresponding menu.
+
 source "drivers/memory/samsung/Kconfig"
 source "drivers/memory/tegra/Kconfig"
 

drivers/memory/Makefile

@@ -22,6 +22,7 @@ obj-$(CONFIG_JZ4780_NEMC)	+= jz4780-nemc.o
 obj-$(CONFIG_MTK_SMI)		+= mtk-smi.o
 obj-$(CONFIG_DA8XX_DDRCTL)	+= da8xx-ddrctl.o
 obj-$(CONFIG_PL353_SMC)		+= pl353-smc.o
+obj-$(CONFIG_RENESAS_RPCIF)	+= renesas-rpc-if.o
 
 obj-$(CONFIG_SAMSUNG_MC)	+= samsung/
 obj-$(CONFIG_TEGRA_MC)		+= tegra/

include/memory/renesas-rpc-if.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Renesas RPC-IF core driver
+ *
+ * Copyright (C) 2018~2019 Renesas Solutions Corp.
+ * Copyright (C) 2019 Macronix International Co., Ltd.
+ * Copyright (C) 2019-2020 Cogent Embedded, Inc.
+ */
+
+#ifndef __RENESAS_RPC_IF_H
+#define __RENESAS_RPC_IF_H
+
+#include <linux/types.h>
+
+enum rpcif_data_dir {
+	RPCIF_NO_DATA,
+	RPCIF_DATA_IN,
+	RPCIF_DATA_OUT,
+};
+
+struct	rpcif_op {
+	struct {
+		u8 buswidth;
+		u8 opcode;
+		bool ddr;
+	} cmd, ocmd;
+
+	struct {
+		u8 nbytes;
+		u8 buswidth;
+		bool ddr;
+		u64 val;
+	} addr;
+
+	struct {
+		u8 ncycles;
+		u8 buswidth;
+	} dummy;
+
+	struct {
+		u8 nbytes;
+		u8 buswidth;
+		bool ddr;
+		u32 val;
+	} option;
+
+	struct {
+		u8 buswidth;
+		unsigned int nbytes;
+		enum rpcif_data_dir dir;
+		bool ddr;
+		union {
+			void *in;
+			const void *out;
+		} buf;
+	} data;
+};
+
+struct	rpcif {
+	struct device *dev;
+	void __iomem *dirmap;
+	struct regmap *regmap;
+	struct reset_control *rstc;
+	size_t size;
+	enum rpcif_data_dir dir;
+	u8 bus_size;
+	void *buffer;
+	u32 xferlen;
+	u32 smcr;
+	u32 smadr;
+	u32 command;		/* DRCMR or SMCMR */
+	u32 option;		/* DROPR or SMOPR */
+	u32 enable;		/* DRENR or SMENR */
+	u32 dummy;		/* DRDMCR or SMDMCR */
+	u32 ddr;		/* DRDRENR or SMDRENR */
+};
+
+int  rpcif_sw_init(struct rpcif *rpc, struct device *dev);
+void rpcif_hw_init(struct rpcif *rpc, bool hyperflash);
+void rpcif_enable_rpm(struct rpcif *rpc);
+void rpcif_disable_rpm(struct rpcif *rpc);
+void rpcif_prepare(struct rpcif *rpc, const struct rpcif_op *op, u64 *offs,
+		   size_t *len);
+int rpcif_manual_xfer(struct rpcif *rpc);
+ssize_t rpcif_dirmap_read(struct rpcif *rpc, u64 offs, size_t len, void *buf);
+
+#endif // __RENESAS_RPC_IF_H