spi: Add support SH Quad SPI driver

This patch adds a driver for Renesas SoC's Quad SPI bus.
This supports with 8 bits per transfer to use with SPI flash.

Signed-off-by: Kouei Abe <kouei.abe.cp@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>

doc/SPI/README.sh_qspi_test

+-------------------------------------------------
+   Simple steps used to test the SH-QSPI at U-Boot
+-------------------------------------------------
+
+#0, Currently, SH-QSPI is used by lager board (Renesas ARM SoC R8A7790)
+    and koelsch board (Renesas ARM SoC R8A7791). These boot from SPI ROM
+    basically. Thus, U-Boot start, SH-QSPI will is operating normally.
+
+#1, build U-Boot and load u-boot.bin
+
+  => tftpboot 40000000 u-boot.bin
+  sh_eth Waiting for PHY auto negotiation to complete.. done
+  sh_eth: 100Base/Half
+  Using sh_eth device
+  TFTP from server 192.168.169.1; our IP address is 192.168.169.79
+  Filename 'u-boot.bin'.
+  Load address: 0x40000000
+  Loading: ############
+    2.5 MiB/s
+  done
+  Bytes transferred = 175364 (2ad04 hex)
+
+#2, Commands to erase/write u-boot to flash device
+
+  Note: This method is description of the lager board. If you want to use the
+  other boards, please change the value according to each environment.
+
+  =>  sf probe 0
+  SF: Detected S25FL512S_256K with page size 512 Bytes, erase size 64 KiB, total 64 MiB
+  => sf erase 80000 40000
+  SF: 262144 bytes @ 0x80000 Erased: OK
+  => sf write 40000000 80000 175364
+  SF: 1528676 bytes @ 0x80000 Written: OK
+  =>
+
+#3, Push reset button.
+
+  If you're written correctly and driver works properly, U-Boot starts.

drivers/spi/Makefile

@@ -30,6 +30,7 @@ obj-$(CONFIG_OMAP3_SPI) += omap3_spi.o
 obj-$(CONFIG_SANDBOX_SPI) += sandbox_spi.o
 obj-$(CONFIG_SOFT_SPI) += soft_spi.o
 obj-$(CONFIG_SH_SPI) += sh_spi.o
+obj-$(CONFIG_SH_QSPI) += sh_qspi.o
 obj-$(CONFIG_FSL_ESPI) += fsl_espi.o
 obj-$(CONFIG_FDT_SPI) += fdt_spi.o
 obj-$(CONFIG_TEGRA20_SFLASH) += tegra20_sflash.o

drivers/spi/sh_qspi.c

+/*
+ * SH QSPI (Quad SPI) driver
+ *
+ * Copyright (C) 2013 Renesas Electronics Corporation
+ * Copyright (C) 2013 Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <spi.h>
+#include <asm/io.h>
+
+/* SH QSPI register bit masks <REG>_<BIT> */
+#define SPCR_MSTR	0x08
+#define SPCR_SPE	0x40
+#define SPSR_SPRFF	0x80
+#define SPSR_SPTEF	0x20
+#define SPPCR_IO3FV	0x04
+#define SPPCR_IO2FV	0x02
+#define SPPCR_IO1FV	0x01
+#define SPBDCR_RXBC0	(1 << 0)
+#define SPCMD_SCKDEN	(1 << 15)
+#define SPCMD_SLNDEN	(1 << 14)
+#define SPCMD_SPNDEN	(1 << 13)
+#define SPCMD_SSLKP	(1 << 7)
+#define SPCMD_BRDV0	(1 << 2)
+#define SPCMD_INIT1	SPCMD_SCKDEN | SPCMD_SLNDEN | \
+			SPCMD_SPNDEN | SPCMD_SSLKP | \
+			SPCMD_BRDV0
+#define SPCMD_INIT2	SPCMD_SPNDEN | SPCMD_SSLKP | \
+			SPCMD_BRDV0
+#define SPBFCR_TXRST	(1 << 7)
+#define SPBFCR_RXRST	(1 << 6)
+
+/* SH QSPI register set */
+struct sh_qspi_regs {
+	unsigned char spcr;
+	unsigned char sslp;
+	unsigned char sppcr;
+	unsigned char spsr;
+	unsigned long spdr;
+	unsigned char spscr;
+	unsigned char spssr;
+	unsigned char spbr;
+	unsigned char spdcr;
+	unsigned char spckd;
+	unsigned char sslnd;
+	unsigned char spnd;
+	unsigned char dummy0;
+	unsigned short spcmd0;
+	unsigned short spcmd1;
+	unsigned short spcmd2;
+	unsigned short spcmd3;
+	unsigned char spbfcr;
+	unsigned char dummy1;
+	unsigned short spbdcr;
+	unsigned long spbmul0;
+	unsigned long spbmul1;
+	unsigned long spbmul2;
+	unsigned long spbmul3;
+};
+
+struct sh_qspi_slave {
+	struct spi_slave	slave;
+	struct sh_qspi_regs	*regs;
+};
+
+static inline struct sh_qspi_slave *to_sh_qspi(struct spi_slave *slave)
+{
+	return container_of(slave, struct sh_qspi_slave, slave);
+}
+
+static void sh_qspi_init(struct sh_qspi_slave *ss)
+{
+	/* QSPI initialize */
+	/* Set master mode only */
+	writeb(SPCR_MSTR, &ss->regs->spcr);
+
+	/* Set SSL signal level */
+	writeb(0x00, &ss->regs->sslp);
+
+	/* Set MOSI signal value when transfer is in idle state */
+	writeb(SPPCR_IO3FV|SPPCR_IO2FV, &ss->regs->sppcr);
+
+	/* Set bit rate. See 58.3.8 Quad Serial Peripheral Interface */
+	writeb(0x01, &ss->regs->spbr);
+
+	/* Disable Dummy Data Transmission */
+	writeb(0x00, &ss->regs->spdcr);
+
+	/* Set clock delay value */
+	writeb(0x00, &ss->regs->spckd);
+
+	/* Set SSL negation delay value */
+	writeb(0x00, &ss->regs->sslnd);
+
+	/* Set next-access delay value */
+	writeb(0x00, &ss->regs->spnd);
+
+	/* Set equence command */
+	writew(SPCMD_INIT2, &ss->regs->spcmd0);
+
+	/* Reset transfer and receive Buffer */
+	setbits_8(&ss->regs->spbfcr, SPBFCR_TXRST|SPBFCR_RXRST);
+
+	/* Clear transfer and receive Buffer control bit */
+	clrbits_8(&ss->regs->spbfcr, SPBFCR_TXRST|SPBFCR_RXRST);
+
+	/* Set equence control method. Use equence0 only */
+	writeb(0x00, &ss->regs->spscr);
+
+	/* Enable SPI function */
+	setbits_8(&ss->regs->spcr, SPCR_SPE);
+}
+
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+	return 1;
+}
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+	struct sh_qspi_slave *ss = to_sh_qspi(slave);
+
+	/* Set master mode only */
+	writeb(SPCR_MSTR, &ss->regs->spcr);
+
+	/* Set command */
+	writew(SPCMD_INIT1, &ss->regs->spcmd0);
+
+	/* Reset transfer and receive Buffer */
+	setbits_8(&ss->regs->spbfcr, SPBFCR_TXRST|SPBFCR_RXRST);
+
+	/* Clear transfer and receive Buffer control bit */
+	clrbits_8(&ss->regs->spbfcr, SPBFCR_TXRST|SPBFCR_RXRST);
+
+	/* Set equence control method. Use equence0 only */
+	writeb(0x00, &ss->regs->spscr);
+
+	/* Enable SPI function */
+	setbits_8(&ss->regs->spcr, SPCR_SPE);
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+	struct sh_qspi_slave *ss = to_sh_qspi(slave);
+
+	/* Disable SPI Function */
+	clrbits_8(&ss->regs->spcr, SPCR_SPE);
+}
+
+void spi_init(void)
+{
+	/* nothing to do */
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+		unsigned int max_hz, unsigned int mode)
+{
+	struct sh_qspi_slave *ss;
+
+	if (!spi_cs_is_valid(bus, cs))
+		return NULL;
+
+	ss = spi_alloc_slave(struct sh_qspi_slave, bus, cs);
+	if (!ss) {
+		printf("SPI_error: Fail to allocate sh_qspi_slave\n");
+		return NULL;
+	}
+
+	ss->regs = (struct sh_qspi_regs *)CONFIG_SH_QSPI_BASE;
+
+	/* Init SH QSPI */
+	sh_qspi_init(ss);
+
+	return &ss->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	struct sh_qspi_slave *spi = to_sh_qspi(slave);
+
+	free(spi);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
+	     void *din, unsigned long flags)
+{
+	struct sh_qspi_slave *ss = to_sh_qspi(slave);
+	unsigned long nbyte;
+	int ret = 0;
+	unsigned char dtdata = 0, drdata;
+	unsigned char *tdata = &dtdata, *rdata = &drdata;
+	unsigned long *spbmul0 = &ss->regs->spbmul0;
+
+	if (dout == NULL && din == NULL) {
+		if (flags & SPI_XFER_END)
+			spi_cs_deactivate(slave);
+		return 0;
+	}
+
+	if (bitlen % 8) {
+		printf("%s: bitlen is not 8bit alined %d", __func__, bitlen);
+		return 1;
+	}
+
+	nbyte = bitlen / 8;
+
+	if (flags & SPI_XFER_BEGIN) {
+		spi_cs_activate(slave);
+
+		/* Set 1048576 byte */
+		writel(0x100000, spbmul0);
+	}
+
+	if (flags & SPI_XFER_END)
+		writel(nbyte, spbmul0);
+
+	if (dout != NULL)
+		tdata = (unsigned char *)dout;
+
+	if (din != NULL)
+		rdata = din;
+
+	while (nbyte > 0) {
+		while (!(readb(&ss->regs->spsr) & SPSR_SPTEF)) {
+			if (ctrlc()) {
+				puts("abort\n");
+				return 1;
+			}
+			udelay(10);
+		}
+
+		writeb(*tdata, (unsigned char *)(&ss->regs->spdr));
+
+		while ((readw(&ss->regs->spbdcr) != SPBDCR_RXBC0)) {
+			if (ctrlc()) {
+				puts("abort\n");
+				return 1;
+			}
+			udelay(1);
+		}
+
+		while (!(readb(&ss->regs->spsr) & SPSR_SPRFF)) {
+			if (ctrlc()) {
+				puts("abort\n");
+				return 1;
+			}
+			udelay(10);
+		}
+
+		*rdata = readb((unsigned char *)(&ss->regs->spdr));
+
+		if (dout != NULL)
+			tdata++;
+		if (din != NULL)
+			rdata++;
+
+		nbyte--;
+	}
+
+	if (flags & SPI_XFER_END)
+		spi_cs_deactivate(slave);
+
+	return ret;
+}