[PATCH v5 2/2] memory: add Renesas RPC-IF driver

[Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>]

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@xxxxxxxxxxx>.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>

---
Changes in version 5:
- added "core" to the driver description comments, removing "R-Car Gen3" from
  the header comment;
- changed " ~ " to '-' in the Renesas copyrights;
- extended Cogent Embedded's copyrights to 2020;
- refreshed the patch.

Changes in version 2:
- stopped using the read cache to avoid the errata in rpcif_dirmap_read();
- zeroed out 'smcr', 'option', and 'dummy' fileds of the 'struct rpcif' and
  reordered the assignments at the start of rpcif_prepare();
- renamed rpcif_io_xfer() to rpcif_manual_xfer();
- switched the lowercase in the hex numbers to the consistent uppercase;
- converted the OCTA #define's into a single bitfield #define and added the
  DDRCAL/HS bits to the PHYCNT register bit #define's;
- write to the register PHYCNT.STRTIM(7) instead of PHYCNT.STRTIM(0) in
  rpcif_hw_init();
- started flushing the read cache via DRCR after updating CMNCR.BSZ;
- changed the operators updating 'struct rpcif' fields from |= to = for the
  command phase setup in rpcif_prepare();
- moved setting rpc->dir before the data phase setup in rpcif_prepare();
- moved pm_runtime_get_sync() call closer to the register setup in
  rpcif_manual_xfer();
- added a dummy read from DRCR after a writing to it in rpcif_hw_init() and
  rpcif_manual_xfer();
- swapped the 'command' and 'smadr' fields in the 'struct rpcif'.
- fixed up the whitespace in rpcif_manual_xfer() and rpcif_probe();
- changed "MFD" to "core" in the MODULE_DESCRIPTION() invocation.

 drivers/memory/Kconfig          |    9 
 drivers/memory/Makefile         |    1 
 drivers/memory/renesas-rpc-if.c |  603 ++++++++++++++++++++++++++++++++++++++++
 include/memory/renesas-rpc-if.h |   87 +++++
 4 files changed, 700 insertions(+)

Index: linux/drivers/memory/Kconfig
===================================================================
--- linux.orig/drivers/memory/Kconfig
+++ linux/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"
 
Index: linux/drivers/memory/Makefile
===================================================================
--- linux.orig/drivers/memory/Makefile
+++ linux/drivers/memory/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_JZ4780_NEMC)	+= jz4780-nemc
 obj-$(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/
Index: linux/drivers/memory/renesas-rpc-if.c
===================================================================
--- /dev/null
+++ linux/drivers/memory/renesas-rpc-if.c
@@ -0,0 +1,603 @@
+// 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+#include <memory/renesas-rpc-if.h>
+
+#define RPCIF_CMNCR		0x0000	/* R/W */
+#define RPCIF_CMNCR_MD		BIT(31)
+#define RPCIF_CMNCR_SFDE	BIT(24) /* undocumented but must be set */
+#define RPCIF_CMNCR_MOIIO3(val)	(((val) & 0x3) << 22)
+#define RPCIF_CMNCR_MOIIO2(val)	(((val) & 0x3) << 20)
+#define RPCIF_CMNCR_MOIIO1(val)	(((val) & 0x3) << 18)
+#define RPCIF_CMNCR_MOIIO0(val)	(((val) & 0x3) << 16)
+#define RPCIF_CMNCR_MOIIO_HIZ	(RPCIF_CMNCR_MOIIO0(3) | \
+				 RPCIF_CMNCR_MOIIO1(3) | \
+				 RPCIF_CMNCR_MOIIO2(3) | RPCIF_CMNCR_MOIIO3(3))
+#define RPCIF_CMNCR_IO3FV(val)	(((val) & 0x3) << 14) /* undocumented */
+#define RPCIF_CMNCR_IO2FV(val)	(((val) & 0x3) << 12) /* undocumented */
+#define RPCIF_CMNCR_IO0FV(val)	(((val) & 0x3) << 8)
+#define RPCIF_CMNCR_IOFV_HIZ	(RPCIF_CMNCR_IO0FV(3) | RPCIF_CMNCR_IO2FV(3) | \
+				 RPCIF_CMNCR_IO3FV(3))
+#define RPCIF_CMNCR_BSZ(val)	(((val) & 0x3) << 0)
+
+#define RPCIF_SSLDR		0x0004	/* R/W */
+#define RPCIF_SSLDR_SPNDL(d)	(((d) & 0x7) << 16)
+#define RPCIF_SSLDR_SLNDL(d)	(((d) & 0x7) << 8)
+#define RPCIF_SSLDR_SCKDL(d)	(((d) & 0x7) << 0)
+
+#define RPCIF_DRCR		0x000C	/* R/W */
+#define RPCIF_DRCR_SSLN		BIT(24)
+#define RPCIF_DRCR_RBURST(v)	((((v) - 1) & 0x1F) << 16)
+#define RPCIF_DRCR_RCF		BIT(9)
+#define RPCIF_DRCR_RBE		BIT(8)
+#define RPCIF_DRCR_SSLE		BIT(0)
+
+#define RPCIF_DRCMR		0x0010	/* R/W */
+#define RPCIF_DRCMR_CMD(c)	(((c) & 0xFF) << 16)
+#define RPCIF_DRCMR_OCMD(c)	(((c) & 0xFF) << 0)
+
+#define RPCIF_DREAR		0x0014	/* R/W */
+#define RPCIF_DREAR_EAV(c)	(((c) & 0xF) << 16)
+#define RPCIF_DREAR_EAC(c)	(((c) & 0x7) << 0)
+
+#define RPCIF_DROPR		0x0018	/* R/W */
+
+#define RPCIF_DRENR		0x001C	/* R/W */
+#define RPCIF_DRENR_CDB(o)	(u32)((((o) & 0x3) << 30))
+#define RPCIF_DRENR_OCDB(o)	(((o) & 0x3) << 28)
+#define RPCIF_DRENR_ADB(o)	(((o) & 0x3) << 24)
+#define RPCIF_DRENR_OPDB(o)	(((o) & 0x3) << 20)
+#define RPCIF_DRENR_DRDB(o)	(((o) & 0x3) << 16)
+#define RPCIF_DRENR_DME		BIT(15)
+#define RPCIF_DRENR_CDE		BIT(14)
+#define RPCIF_DRENR_OCDE	BIT(12)
+#define RPCIF_DRENR_ADE(v)	(((v) & 0xF) << 8)
+#define RPCIF_DRENR_OPDE(v)	(((v) & 0xF) << 4)
+
+#define RPCIF_SMCR		0x0020	/* R/W */
+#define RPCIF_SMCR_SSLKP	BIT(8)
+#define RPCIF_SMCR_SPIRE	BIT(2)
+#define RPCIF_SMCR_SPIWE	BIT(1)
+#define RPCIF_SMCR_SPIE		BIT(0)
+
+#define RPCIF_SMCMR		0x0024	/* R/W */
+#define RPCIF_SMCMR_CMD(c)	(((c) & 0xFF) << 16)
+#define RPCIF_SMCMR_OCMD(c)	(((c) & 0xFF) << 0)
+
+#define RPCIF_SMADR		0x0028	/* R/W */
+
+#define RPCIF_SMOPR		0x002C	/* R/W */
+#define RPCIF_SMOPR_OPD3(o)	(((o) & 0xFF) << 24)
+#define RPCIF_SMOPR_OPD2(o)	(((o) & 0xFF) << 16)
+#define RPCIF_SMOPR_OPD1(o)	(((o) & 0xFF) << 8)
+#define RPCIF_SMOPR_OPD0(o)	(((o) & 0xFF) << 0)
+
+#define RPCIF_SMENR		0x0030	/* R/W */
+#define RPCIF_SMENR_CDB(o)	(((o) & 0x3) << 30)
+#define RPCIF_SMENR_OCDB(o)	(((o) & 0x3) << 28)
+#define RPCIF_SMENR_ADB(o)	(((o) & 0x3) << 24)
+#define RPCIF_SMENR_OPDB(o)	(((o) & 0x3) << 20)
+#define RPCIF_SMENR_SPIDB(o)	(((o) & 0x3) << 16)
+#define RPCIF_SMENR_DME		BIT(15)
+#define RPCIF_SMENR_CDE		BIT(14)
+#define RPCIF_SMENR_OCDE	BIT(12)
+#define RPCIF_SMENR_ADE(v)	(((v) & 0xF) << 8)
+#define RPCIF_SMENR_OPDE(v)	(((v) & 0xF) << 4)
+#define RPCIF_SMENR_SPIDE(v)	(((v) & 0xF) << 0)
+
+#define RPCIF_SMRDR0		0x0038	/* R */
+#define RPCIF_SMRDR1		0x003C	/* R */
+#define RPCIF_SMWDR0		0x0040	/* W */
+#define RPCIF_SMWDR1		0x0044	/* W */
+
+#define RPCIF_CMNSR		0x0048	/* R */
+#define RPCIF_CMNSR_SSLF	BIT(1)
+#define RPCIF_CMNSR_TEND	BIT(0)
+
+#define RPCIF_DRDMCR		0x0058	/* R/W */
+#define RPCIF_DMDMCR_DMCYC(v)	((((v) - 1) & 0x1F) << 0)
+
+#define RPCIF_DRDRENR		0x005C	/* R/W */
+#define RPCIF_DRDRENR_HYPE(v)	(((v) & 0x7) << 12)
+#define RPCIF_DRDRENR_ADDRE	BIT(8)
+#define RPCIF_DRDRENR_OPDRE	BIT(4)
+#define RPCIF_DRDRENR_DRDRE	BIT(0)
+
+#define RPCIF_SMDMCR		0x0060	/* R/W */
+#define RPCIF_SMDMCR_DMCYC(v)	((((v) - 1) & 0x1F) << 0)
+
+#define RPCIF_SMDRENR		0x0064	/* R/W */
+#define RPCIF_SMDRENR_HYPE(v)	(((v) & 0x7) << 12)
+#define RPCIF_SMDRENR_ADDRE	BIT(8)
+#define RPCIF_SMDRENR_OPDRE	BIT(4)
+#define RPCIF_SMDRENR_SPIDRE	BIT(0)
+
+#define RPCIF_PHYCNT		0x007C	/* R/W */
+#define RPCIF_PHYCNT_CAL	BIT(31)
+#define RPCIF_PHYCNT_OCTA(v)	(((v) & 0x3) << 22)
+#define RPCIF_PHYCNT_EXDS	BIT(21)
+#define RPCIF_PHYCNT_OCT	BIT(20)
+#define RPCIF_PHYCNT_DDRCAL	BIT(19)
+#define RPCIF_PHYCNT_HS		BIT(18)
+#define RPCIF_PHYCNT_STRTIM(v)	(((v) & 0x7) << 15)
+#define RPCIF_PHYCNT_WBUF2	BIT(4)
+#define RPCIF_PHYCNT_WBUF	BIT(2)
+#define RPCIF_PHYCNT_PHYMEM(v)	(((v) & 0x3) << 0)
+
+#define RPCIF_PHYOFFSET1	0x0080	/* R/W */
+#define RPCIF_PHYOFFSET1_DDRTMG(v) (((v) & 0x3) << 28)
+
+#define RPCIF_PHYOFFSET2	0x0084	/* R/W */
+#define RPCIF_PHYOFFSET2_OCTTMG(v) (((v) & 0x7) << 8)
+
+#define RPCIF_PHYINT		0x0088	/* R/W */
+#define RPCIF_PHYINT_WPVAL	BIT(1)
+
+#define RPCIF_DIRMAP_SIZE	0x4000000
+
+static const struct regmap_range rpcif_volatile_ranges[] = {
+	regmap_reg_range(RPCIF_SMRDR0, RPCIF_SMRDR1),
+	regmap_reg_range(RPCIF_SMWDR0, RPCIF_SMWDR1),
+	regmap_reg_range(RPCIF_CMNSR, RPCIF_CMNSR),
+};
+
+static const struct regmap_access_table rpcif_volatile_table = {
+	.yes_ranges	= rpcif_volatile_ranges,
+	.n_yes_ranges	= ARRAY_SIZE(rpcif_volatile_ranges),
+};
+
+static const struct regmap_config rpcif_regmap_config = {
+	.reg_bits	= 32,
+	.val_bits	= 32,
+	.reg_stride	= 4,
+	.fast_io	= true,
+	.max_register	= RPCIF_PHYINT,
+	.volatile_table	= &rpcif_volatile_table,
+};
+
+int rpcif_sw_init(struct rpcif *rpc, struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct resource *res;
+	void __iomem *base;
+
+	rpc->dev = dev;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	rpc->regmap = devm_regmap_init_mmio(&pdev->dev, base,
+					    &rpcif_regmap_config);
+	if (IS_ERR(rpc->regmap)) {
+		dev_err(&pdev->dev,
+			"failed to init regmap for rpcif, error %ld\n",
+			PTR_ERR(rpc->regmap));
+		return	PTR_ERR(rpc->regmap);
+	}
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dirmap");
+	rpc->size = resource_size(res);
+	rpc->dirmap = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(rpc->dirmap))
+		rpc->dirmap = NULL;
+
+	rpc->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(rpc->rstc))
+		return PTR_ERR(rpc->rstc);
+
+	return 0;
+}
+EXPORT_SYMBOL(rpcif_sw_init);
+
+void rpcif_enable_rpm(struct rpcif *rpc)
+{
+	pm_runtime_enable(rpc->dev);
+}
+EXPORT_SYMBOL(rpcif_enable_rpm);
+
+void rpcif_disable_rpm(struct rpcif *rpc)
+{
+	pm_runtime_put_sync(rpc->dev);
+}
+EXPORT_SYMBOL(rpcif_disable_rpm);
+
+void rpcif_hw_init(struct rpcif *rpc, bool hyperflash)
+{
+	u32 dummy;
+
+	pm_runtime_get_sync(rpc->dev);
+
+	/*
+	 * NOTE: The 0x260 are undocumented bits, but they must be set.
+	 *	 RPCIF_PHYCNT_STRTIM is strobe timing adjustment bits,
+	 *	 0x0 : the delay is biggest,
+	 *	 0x1 : the delay is 2nd biggest,
+	 *	 On H3 ES1.x, the value should be 0, while on others,
+	 *	 the value should be 7.
+	 */
+	regmap_write(rpc->regmap, RPCIF_PHYCNT, RPCIF_PHYCNT_STRTIM(7) |
+		     RPCIF_PHYCNT_PHYMEM(hyperflash ? 3 : 0) | 0x260);
+
+	/*
+	 * NOTE: The 0x1511144 are undocumented bits, but they must be set
+	 *       for RPCIF_PHYOFFSET1.
+	 *	 The 0x31 are undocumented bits, but they must be set
+	 *	 for RPCIF_PHYOFFSET2.
+	 */
+	regmap_write(rpc->regmap, RPCIF_PHYOFFSET1, 0x1511144 |
+		     RPCIF_PHYOFFSET1_DDRTMG(3));
+	regmap_write(rpc->regmap, RPCIF_PHYOFFSET2, 0x31 |
+		     RPCIF_PHYOFFSET2_OCTTMG(4));
+
+	if (hyperflash)
+		regmap_update_bits(rpc->regmap, RPCIF_PHYINT,
+				   RPCIF_PHYINT_WPVAL, 0);
+
+	regmap_write(rpc->regmap, RPCIF_CMNCR, RPCIF_CMNCR_SFDE |
+		     RPCIF_CMNCR_MOIIO_HIZ | RPCIF_CMNCR_IOFV_HIZ |
+		     RPCIF_CMNCR_BSZ(hyperflash ? 1 : 0));
+	/* Set RCF after BSZ update */
+	regmap_write(rpc->regmap, RPCIF_DRCR, RPCIF_DRCR_RCF);
+	/* Dummy read according to spec */
+	regmap_read(rpc->regmap, RPCIF_DRCR, &dummy);
+	regmap_write(rpc->regmap, RPCIF_SSLDR, RPCIF_SSLDR_SPNDL(7) |
+		     RPCIF_SSLDR_SLNDL(7) | RPCIF_SSLDR_SCKDL(7));
+
+	pm_runtime_put(rpc->dev);
+
+	rpc->bus_size = hyperflash ? 2 : 1;
+}
+EXPORT_SYMBOL(rpcif_hw_init);
+
+static int wait_msg_xfer_end(struct rpcif *rpc)
+{
+	u32 sts;
+
+	return regmap_read_poll_timeout(rpc->regmap, RPCIF_CMNSR, sts,
+					sts & RPCIF_CMNSR_TEND, 0,
+					USEC_PER_SEC);
+}
+
+static u8 rpcif_bits_set(struct rpcif *rpc, u32 nbytes)
+{
+	if (rpc->bus_size == 2)
+		nbytes /= 2;
+	nbytes = clamp(nbytes, 1U, 4U);
+	return GENMASK(3, 4 - nbytes);
+}
+
+static u8 rpcif_bit_size(u8 buswidth)
+{
+	return buswidth > 4 ? 2 : ilog2(buswidth);
+}
+
+void rpcif_prepare(struct rpcif *rpc, const struct rpcif_op *op, u64 *offs,
+		   size_t *len)
+{
+	rpc->smcr = 0;
+	rpc->smadr = 0;
+	rpc->enable = 0;
+	rpc->command = 0;
+	rpc->option = 0;
+	rpc->dummy = 0;
+	rpc->ddr = 0;
+	rpc->xferlen = 0;
+
+	if (op->cmd.buswidth) {
+		rpc->enable  = RPCIF_SMENR_CDE |
+			RPCIF_SMENR_CDB(rpcif_bit_size(op->cmd.buswidth));
+		rpc->command = RPCIF_SMCMR_CMD(op->cmd.opcode);
+		if (op->cmd.ddr)
+			rpc->ddr = RPCIF_SMDRENR_HYPE(0x5);
+	}
+	if (op->ocmd.buswidth) {
+		rpc->enable  |= RPCIF_SMENR_OCDE |
+			RPCIF_SMENR_OCDB(rpcif_bit_size(op->ocmd.buswidth));
+		rpc->command |= RPCIF_SMCMR_OCMD(op->ocmd.opcode);
+	}
+
+	if (op->addr.buswidth) {
+		rpc->enable |=
+			RPCIF_SMENR_ADB(rpcif_bit_size(op->addr.buswidth));
+		if (op->addr.nbytes == 4)
+			rpc->enable |= RPCIF_SMENR_ADE(0xF);
+		else
+			rpc->enable |= RPCIF_SMENR_ADE(GENMASK(
+						2, 3 - op->addr.nbytes));
+		if (op->addr.ddr)
+			rpc->ddr |= RPCIF_SMDRENR_ADDRE;
+
+		if (offs && len)
+			rpc->smadr = *offs;
+		else
+			rpc->smadr = op->addr.val;
+	}
+
+	if (op->dummy.buswidth) {
+		rpc->enable |= RPCIF_SMENR_DME;
+		rpc->dummy = RPCIF_SMDMCR_DMCYC(op->dummy.ncycles /
+						op->dummy.buswidth);
+	}
+
+	if (op->option.buswidth) {
+		rpc->enable |= RPCIF_SMENR_OPDE(
+			rpcif_bits_set(rpc, op->option.nbytes)) |
+			RPCIF_SMENR_OPDB(rpcif_bit_size(op->option.buswidth));
+		if (op->option.ddr)
+			rpc->ddr |= RPCIF_SMDRENR_OPDRE;
+		rpc->option = op->option.val;
+	}
+
+	rpc->dir = op->data.dir;
+	if (op->data.buswidth) {
+		u32 nbytes;
+
+		rpc->buffer = op->data.buf.in;
+		switch (op->data.dir) {
+		case RPCIF_DATA_IN:
+			rpc->smcr = RPCIF_SMCR_SPIRE;
+			break;
+		case RPCIF_DATA_OUT:
+			rpc->smcr = RPCIF_SMCR_SPIWE;
+			break;
+		default:
+			break;
+		}
+		if (op->data.ddr)
+			rpc->ddr |= RPCIF_SMDRENR_SPIDRE;
+
+		if (offs && len)
+			nbytes = *len;
+		else
+			nbytes = op->data.nbytes;
+		rpc->xferlen = nbytes;
+
+		rpc->enable |= RPCIF_SMENR_SPIDE(rpcif_bits_set(rpc, nbytes)) |
+			RPCIF_SMENR_SPIDB(rpcif_bit_size(op->data.buswidth));
+	}
+}
+EXPORT_SYMBOL(rpcif_prepare);
+
+int rpcif_manual_xfer(struct rpcif *rpc)
+{
+	u32 smenr, smcr, pos = 0, max = 4;
+	int ret = 0;
+
+	if (rpc->bus_size == 2)
+		max = 8;
+
+	pm_runtime_get_sync(rpc->dev);
+
+	regmap_update_bits(rpc->regmap, RPCIF_PHYCNT,
+			   RPCIF_PHYCNT_CAL, RPCIF_PHYCNT_CAL);
+	regmap_update_bits(rpc->regmap, RPCIF_CMNCR,
+			   RPCIF_CMNCR_MD, RPCIF_CMNCR_MD);
+	regmap_write(rpc->regmap, RPCIF_SMCMR, rpc->command);
+	regmap_write(rpc->regmap, RPCIF_SMOPR, rpc->option);
+	regmap_write(rpc->regmap, RPCIF_SMDMCR, rpc->dummy);
+	regmap_write(rpc->regmap, RPCIF_SMDRENR, rpc->ddr);
+	smenr = rpc->enable;
+
+	switch (rpc->dir) {
+	case RPCIF_DATA_OUT:
+		while (pos < rpc->xferlen) {
+			u32 nbytes = rpc->xferlen - pos;
+			u32 data[2];
+
+			smcr = rpc->smcr | RPCIF_SMCR_SPIE;
+			if (nbytes > max) {
+				nbytes = max;
+				smcr |= RPCIF_SMCR_SSLKP;
+			}
+
+			memcpy(data, rpc->buffer + pos, nbytes);
+			if (nbytes > 4) {
+				regmap_write(rpc->regmap, RPCIF_SMWDR1,
+					     data[0]);
+				regmap_write(rpc->regmap, RPCIF_SMWDR0,
+					     data[1]);
+			} else if (nbytes > 2) {
+				regmap_write(rpc->regmap, RPCIF_SMWDR0,
+					     data[0]);
+			} else	{
+				regmap_write(rpc->regmap, RPCIF_SMWDR0,
+					     data[0] << 16);
+			}
+
+			regmap_write(rpc->regmap, RPCIF_SMADR,
+				     rpc->smadr + pos);
+			regmap_write(rpc->regmap, RPCIF_SMENR, smenr);
+			regmap_write(rpc->regmap, RPCIF_SMCR, smcr);
+			ret = wait_msg_xfer_end(rpc);
+			if (ret)
+				goto err_out;
+
+			pos += nbytes;
+			smenr = rpc->enable &
+				~RPCIF_SMENR_CDE & ~RPCIF_SMENR_ADE(0xF);
+		}
+		break;
+	case RPCIF_DATA_IN:
+		/*
+		 * RPC-IF spoils the data for the commands without an address
+		 * phase (like RDID) in the manual mode, so we'll have to work
+		 * around this issue by using the external address space read
+		 * mode instead.
+		 */
+		if (!(smenr & RPCIF_SMENR_ADE(0xF)) && rpc->dirmap) {
+			u32 dummy;
+
+			regmap_update_bits(rpc->regmap, RPCIF_CMNCR,
+					   RPCIF_CMNCR_MD, 0);
+			regmap_write(rpc->regmap, RPCIF_DRCR,
+				     RPCIF_DRCR_RBURST(32) | RPCIF_DRCR_RBE);
+			regmap_write(rpc->regmap, RPCIF_DRCMR, rpc->command);
+			regmap_write(rpc->regmap, RPCIF_DREAR,
+				     RPCIF_DREAR_EAC(1));
+			regmap_write(rpc->regmap, RPCIF_DROPR, rpc->option);
+			regmap_write(rpc->regmap, RPCIF_DRENR,
+				     smenr & ~RPCIF_SMENR_SPIDE(0xF));
+			regmap_write(rpc->regmap, RPCIF_DRDMCR,  rpc->dummy);
+			regmap_write(rpc->regmap, RPCIF_DRDRENR, rpc->ddr);
+			memcpy_fromio(rpc->buffer, rpc->dirmap, rpc->xferlen);
+			regmap_write(rpc->regmap, RPCIF_DRCR, RPCIF_DRCR_RCF);
+			/* Dummy read according to spec */
+			regmap_read(rpc->regmap, RPCIF_DRCR, &dummy);
+			break;
+		}
+		while (pos < rpc->xferlen) {
+			u32 nbytes = rpc->xferlen - pos;
+			u32 data[2];
+
+			if (nbytes > max)
+				nbytes = max;
+
+			regmap_write(rpc->regmap, RPCIF_SMADR,
+				     rpc->smadr + pos);
+			regmap_write(rpc->regmap, RPCIF_SMENR, smenr);
+			regmap_write(rpc->regmap, RPCIF_SMCR,
+				     rpc->smcr | RPCIF_SMCR_SPIE);
+			ret = wait_msg_xfer_end(rpc);
+			if (ret)
+				goto err_out;
+
+			if (nbytes > 4) {
+				regmap_read(rpc->regmap, RPCIF_SMRDR1,
+					    &data[0]);
+				regmap_read(rpc->regmap, RPCIF_SMRDR0,
+					    &data[1]);
+			} else if (nbytes > 2) {
+				regmap_read(rpc->regmap, RPCIF_SMRDR0,
+					    &data[0]);
+			} else	{
+				regmap_read(rpc->regmap, RPCIF_SMRDR0,
+					    &data[0]);
+				data[0] >>= 16;
+			}
+			memcpy(rpc->buffer + pos, data, nbytes);
+
+			pos += nbytes;
+		}
+		break;
+	default:
+		regmap_write(rpc->regmap, RPCIF_SMENR, rpc->enable);
+		regmap_write(rpc->regmap, RPCIF_SMCR,
+			     rpc->smcr | RPCIF_SMCR_SPIE);
+		ret = wait_msg_xfer_end(rpc);
+		if (ret)
+			goto err_out;
+	}
+
+exit:
+	pm_runtime_put(rpc->dev);
+	return ret;
+
+err_out:
+	ret = reset_control_reset(rpc->rstc);
+	rpcif_hw_init(rpc, rpc->bus_size == 2);
+	goto exit;
+}
+EXPORT_SYMBOL(rpcif_manual_xfer);
+
+ssize_t rpcif_dirmap_read(struct rpcif *rpc, u64 offs, size_t len, void *buf)
+{
+	loff_t from = offs & (RPCIF_DIRMAP_SIZE - 1);
+	size_t size = RPCIF_DIRMAP_SIZE - from;
+
+	if (len > size)
+		len = size;
+
+	pm_runtime_get_sync(rpc->dev);
+
+	regmap_update_bits(rpc->regmap, RPCIF_CMNCR, RPCIF_CMNCR_MD, 0);
+	regmap_write(rpc->regmap, RPCIF_DRCR, 0);
+	regmap_write(rpc->regmap, RPCIF_DRCMR, rpc->command);
+	regmap_write(rpc->regmap, RPCIF_DREAR,
+		     RPCIF_DREAR_EAV(offs >> 25) | RPCIF_DREAR_EAC(1));
+	regmap_write(rpc->regmap, RPCIF_DROPR, rpc->option);
+	regmap_write(rpc->regmap, RPCIF_DRENR,
+		     rpc->enable & ~RPCIF_SMENR_SPIDE(0xF));
+	regmap_write(rpc->regmap, RPCIF_DRDMCR, rpc->dummy);
+	regmap_write(rpc->regmap, RPCIF_DRDRENR, rpc->ddr);
+
+	memcpy_fromio(buf, rpc->dirmap + from, len);
+
+	pm_runtime_put(rpc->dev);
+
+	return len;
+}
+EXPORT_SYMBOL(rpcif_dirmap_read);
+
+static int rpcif_probe(struct platform_device *pdev)
+{
+	struct platform_device *vdev;
+	struct device_node *flash;
+	const char *name;
+
+	flash = of_get_next_child(pdev->dev.of_node, NULL);
+	if (!flash) {
+		dev_warn(&pdev->dev, "no flash node found\n");
+		return -ENODEV;
+	}
+
+	if (of_device_is_compatible(flash, "jedec,spi-nor")) {
+		name = "rpc-if-spi";
+	} else if (of_device_is_compatible(flash, "cfi-flash")) {
+		name = "rpc-if-hyperflash";
+	} else	{
+		dev_warn(&pdev->dev, "unknown flash type\n");
+		return -ENODEV;
+	}
+
+	vdev = platform_device_alloc(name, pdev->id);
+	if (!vdev)
+		return -ENOMEM;
+	vdev->dev.parent = &pdev->dev;
+	platform_set_drvdata(pdev, vdev);
+	return platform_device_add(vdev);
+}
+
+static int rpcif_remove(struct platform_device *pdev)
+{
+	struct platform_device *vdev = platform_get_drvdata(pdev);
+
+	platform_device_unregister(vdev);
+
+	return 0;
+}
+
+static const struct of_device_id rpcif_of_match[] = {
+	{ .compatible = "renesas,rcar-gen3-rpc-if", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rpcif_of_match);
+
+static struct platform_driver rpcif_driver = {
+	.probe	= rpcif_probe,
+	.remove	= rpcif_remove,
+	.driver = {
+		.name =	"rpc-if",
+		.of_match_table = rpcif_of_match,
+	},
+};
+module_platform_driver(rpcif_driver);
+
+MODULE_DESCRIPTION("Renesas RPC-IF core driver");
+MODULE_LICENSE("GPL v2");
Index: linux/include/memory/renesas-rpc-if.h
===================================================================
--- /dev/null
+++ linux/include/memory/renesas-rpc-if.h
@@ -0,0 +1,87 @@
+/* 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