rockchip: Add SPI driver

Add a SPI driver for the Rockchip RK3288, using driver model. It should work
for other Rockchip SoCs also.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/arm/include/asm/arch-rockchip/clock.h

@@ -35,6 +35,26 @@ static inline int rk_pll_id(enum rk_clk_id clk_id)
 	return clk_id - 1;
 }
 
+/**
+ * clk_get_divisor() - Calculate the required clock divisior
+ *
+ * Given an input rate and a required output_rate, calculate the Rockchip
+ * divisor needed to achieve this.
+ *
+ * @input_rate:		Input clock rate in Hz
+ * @output_rate:	Output clock rate in Hz
+ * @return divisor register value to use
+ */
+static inline u32 clk_get_divisor(ulong input_rate, uint output_rate)
+{
+	uint clk_div;
+
+	clk_div = input_rate / output_rate;
+	clk_div = (clk_div + 1) & 0xfffe;
+
+	return clk_div;
+}
+
 /**
  * rockchip_get_cru() - get a pointer to the clock/reset unit registers
  *

drivers/spi/Kconfig

@@ -58,6 +58,14 @@ config ICH_SPI
 	  access the SPI NOR flash on platforms embedding this Intel
 	  ICH IP core.
 
+config ROCKCHIP_SPI
+	bool "Rockchip SPI driver"
+	help
+	  Enable the Rockchip SPI driver, used to access SPI NOR flash and
+	  other SPI peripherals (such as the Chrome OS EC) on Rockchip SoCs.
+	  This uses driver model and requires a device tree binding to
+	  operate.
+
 config SANDBOX_SPI
 	bool "Sandbox SPI driver"
 	depends on SANDBOX && DM

drivers/spi/Makefile

@@ -39,6 +39,7 @@ obj-$(CONFIG_MPC8XXX_SPI) += mpc8xxx_spi.o
 obj-$(CONFIG_MXC_SPI) += mxc_spi.o
 obj-$(CONFIG_MXS_SPI) += mxs_spi.o
 obj-$(CONFIG_OMAP3_SPI) += omap3_spi.o
+obj-$(CONFIG_ROCKCHIP_SPI) += rk_spi.o
 obj-$(CONFIG_SANDBOX_SPI) += sandbox_spi.o
 obj-$(CONFIG_SH_SPI) += sh_spi.o
 obj-$(CONFIG_SH_QSPI) += sh_qspi.o

drivers/spi/rk_spi.c

@@ -0,0 +1,374 @@
+/*
+ * spi driver for rockchip
+ *
+ * (C) Copyright 2015 Google, Inc
+ *
+ * (C) Copyright 2008-2013 Rockchip Electronics
+ * Peter, Software Engineering, <superpeter.cai@gmail.com>.
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <errno.h>
+#include <spi.h>
+#include <asm/errno.h>
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/periph.h>
+#include <dm/pinctrl.h>
+#include "rk_spi.h"
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* Change to 1 to output registers at the start of each transaction */
+#define DEBUG_RK_SPI	0
+
+struct rockchip_spi_platdata {
+	enum periph_id periph_id;
+	struct udevice *pinctrl;
+	s32 frequency;		/* Default clock frequency, -1 for none */
+	fdt_addr_t base;
+	uint deactivate_delay_us;	/* Delay to wait after deactivate */
+};
+
+struct rockchip_spi_priv {
+	struct rockchip_spi *regs;
+	struct udevice *clk_gpll;
+	unsigned int max_freq;
+	unsigned int mode;
+	enum periph_id periph_id;	/* Peripheral ID for this device */
+	ulong last_transaction_us;	/* Time of last transaction end */
+	u8 bits_per_word;		/* max 16 bits per word */
+	u8 n_bytes;
+	unsigned int speed_hz;
+	unsigned int tmode;
+	uint input_rate;
+};
+
+#define SPI_FIFO_DEPTH		32
+
+static void rkspi_dump_regs(struct rockchip_spi *regs)
+{
+	debug("ctrl0: \t\t0x%08x\n", readl(&regs->ctrlr0));
+	debug("ctrl1: \t\t0x%08x\n", readl(&regs->ctrlr1));
+	debug("ssienr: \t\t0x%08x\n", readl(&regs->enr));
+	debug("ser: \t\t0x%08x\n", readl(&regs->ser));
+	debug("baudr: \t\t0x%08x\n", readl(&regs->baudr));
+	debug("txftlr: \t\t0x%08x\n", readl(&regs->txftlr));
+	debug("rxftlr: \t\t0x%08x\n", readl(&regs->rxftlr));
+	debug("txflr: \t\t0x%08x\n", readl(&regs->txflr));
+	debug("rxflr: \t\t0x%08x\n", readl(&regs->rxflr));
+	debug("sr: \t\t0x%08x\n", readl(&regs->sr));
+	debug("imr: \t\t0x%08x\n", readl(&regs->imr));
+	debug("isr: \t\t0x%08x\n", readl(&regs->isr));
+	debug("dmacr: \t\t0x%08x\n", readl(&regs->dmacr));
+	debug("dmatdlr: \t0x%08x\n", readl(&regs->dmatdlr));
+	debug("dmardlr: \t0x%08x\n", readl(&regs->dmardlr));
+}
+
+static void rkspi_enable_chip(struct rockchip_spi *regs, bool enable)
+{
+	writel(enable ? 1 : 0, &regs->enr);
+}
+
+static void rkspi_set_clk(struct rockchip_spi_priv *priv, uint speed)
+{
+	uint clk_div;
+
+	clk_div = clk_get_divisor(priv->input_rate, speed);
+	debug("spi speed %u, div %u\n", speed, clk_div);
+
+	writel(clk_div, &priv->regs->baudr);
+}
+
+static int rkspi_wait_till_not_busy(struct rockchip_spi *regs)
+{
+	unsigned long start;
+
+	start = get_timer(0);
+	while (readl(&regs->sr) & SR_BUSY) {
+		if (get_timer(start) > ROCKCHIP_SPI_TIMEOUT_MS) {
+			debug("RK SPI: Status keeps busy for 1000us after a read/write!\n");
+			return -ETIMEDOUT;
+		}
+	}
+
+	return 0;
+}
+
+static void spi_cs_activate(struct rockchip_spi *regs, uint cs)
+{
+	debug("activate cs%u\n", cs);
+	writel(1 << cs, &regs->ser);
+}
+
+static void spi_cs_deactivate(struct rockchip_spi *regs, uint cs)
+{
+	debug("deactivate cs%u\n", cs);
+	writel(0, &regs->ser);
+}
+
+static int rockchip_spi_ofdata_to_platdata(struct udevice *bus)
+{
+	struct rockchip_spi_platdata *plat = bus->platdata;
+	const void *blob = gd->fdt_blob;
+	int node = bus->of_offset;
+	int ret;
+
+	plat->base = dev_get_addr(bus);
+	ret = uclass_get_device(UCLASS_PINCTRL, 0, &plat->pinctrl);
+	if (ret)
+		return ret;
+	ret = pinctrl_get_periph_id(plat->pinctrl, bus);
+
+	if (ret < 0) {
+		debug("%s: Could not get peripheral ID for %s: %d\n", __func__,
+		      bus->name, ret);
+		return -FDT_ERR_NOTFOUND;
+	}
+	plat->periph_id = ret;
+
+	plat->frequency = fdtdec_get_int(blob, node, "spi-max-frequency",
+					50000000);
+	plat->deactivate_delay_us = fdtdec_get_int(blob, node,
+					"spi-deactivate-delay", 0);
+	debug("%s: base=%x, periph_id=%d, max-frequency=%d, deactivate_delay=%d\n",
+	      __func__, plat->base, plat->periph_id, plat->frequency,
+	      plat->deactivate_delay_us);
+
+	return 0;
+}
+
+static int rockchip_spi_probe(struct udevice *bus)
+{
+	struct rockchip_spi_platdata *plat = dev_get_platdata(bus);
+	struct rockchip_spi_priv *priv = dev_get_priv(bus);
+	int ret;
+
+	debug("%s: probe\n", __func__);
+	priv->regs = (struct rockchip_spi *)plat->base;
+
+	priv->last_transaction_us = timer_get_us();
+	priv->max_freq = plat->frequency;
+	priv->periph_id = plat->periph_id;
+	ret = uclass_get_device(UCLASS_CLK, CLK_GENERAL, &priv->clk_gpll);
+	if (ret) {
+		debug("%s: Failed to find CLK_GENERAL: %d\n", __func__, ret);
+		return ret;
+	}
+
+	/*
+	 * Use 99 MHz as our clock since it divides nicely into 594 MHz which
+	 * is the assumed speed for CLK_GENERAL.
+	 */
+	ret = clk_set_periph_rate(priv->clk_gpll, plat->periph_id, 99000000);
+	if (ret < 0) {
+		debug("%s: Failed to set clock: %d\n", __func__, ret);
+		return ret;
+	}
+	priv->input_rate = ret;
+	debug("%s: rate = %u\n", __func__, priv->input_rate);
+	priv->bits_per_word = 8;
+	priv->tmode = TMOD_TR; /* Tx & Rx */
+
+	return 0;
+}
+
+static int rockchip_spi_claim_bus(struct udevice *dev)
+{
+	struct udevice *bus = dev->parent;
+	struct rockchip_spi_platdata *plat = dev_get_platdata(bus);
+	struct rockchip_spi_priv *priv = dev_get_priv(bus);
+	struct rockchip_spi *regs = priv->regs;
+	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
+	u8 spi_dfs, spi_tf;
+	uint ctrlr0;
+	int ret;
+
+	/* Disable the SPI hardware */
+	rkspi_enable_chip(regs, 0);
+
+	switch (priv->bits_per_word) {
+	case 8:
+		priv->n_bytes = 1;
+		spi_dfs = DFS_8BIT;
+		spi_tf = HALF_WORD_OFF;
+		break;
+	case 16:
+		priv->n_bytes = 2;
+		spi_dfs = DFS_16BIT;
+		spi_tf = HALF_WORD_ON;
+		break;
+	default:
+		debug("%s: unsupported bits: %dbits\n", __func__,
+		      priv->bits_per_word);
+		return -EPROTONOSUPPORT;
+	}
+
+	rkspi_set_clk(priv, priv->speed_hz);
+
+	/* Operation Mode */
+	ctrlr0 = OMOD_MASTER << OMOD_SHIFT;
+
+	/* Data Frame Size */
+	ctrlr0 |= spi_dfs & DFS_MASK << DFS_SHIFT;
+
+	/* set SPI mode 0..3 */
+	if (priv->mode & SPI_CPOL)
+		ctrlr0 |= SCOL_HIGH << SCOL_SHIFT;
+	if (priv->mode & SPI_CPHA)
+		ctrlr0 |= SCPH_TOGSTA << SCPH_SHIFT;
+
+	/* Chip Select Mode */
+	ctrlr0 |= CSM_KEEP << CSM_SHIFT;
+
+	/* SSN to Sclk_out delay */
+	ctrlr0 |= SSN_DELAY_ONE << SSN_DELAY_SHIFT;
+
+	/* Serial Endian Mode */
+	ctrlr0 |= SEM_LITTLE << SEM_SHIFT;
+
+	/* First Bit Mode */
+	ctrlr0 |= FBM_MSB << FBM_SHIFT;
+
+	/* Byte and Halfword Transform */
+	ctrlr0 |= (spi_tf & HALF_WORD_MASK) << HALF_WORD_TX_SHIFT;
+
+	/* Rxd Sample Delay */
+	ctrlr0 |= 0 << RXDSD_SHIFT;
+
+	/* Frame Format */
+	ctrlr0 |= FRF_SPI << FRF_SHIFT;
+
+	/* Tx and Rx mode */
+	ctrlr0 |= (priv->tmode & TMOD_MASK) << TMOD_SHIFT;
+
+	writel(ctrlr0, &regs->ctrlr0);
+
+	ret = pinctrl_request(plat->pinctrl, priv->periph_id, slave_plat->cs);
+	if (ret) {
+		debug("%s: Cannot request pinctrl: %d\n", __func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int rockchip_spi_release_bus(struct udevice *dev)
+{
+	return 0;
+}
+
+static int rockchip_spi_xfer(struct udevice *dev, unsigned int bitlen,
+			   const void *dout, void *din, unsigned long flags)
+{
+	struct udevice *bus = dev->parent;
+	struct rockchip_spi_priv *priv = dev_get_priv(bus);
+	struct rockchip_spi *regs = priv->regs;
+	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
+	int len = bitlen >> 3;
+	const u8 *out = dout;
+	u8 *in = din;
+	int toread, towrite;
+	int ret;
+
+	debug("%s: dout=%p, din=%p, len=%x, flags=%lx\n", __func__, dout, din,
+	      len, flags);
+	if (DEBUG_RK_SPI)
+		rkspi_dump_regs(regs);
+
+	/* Assert CS before transfer */
+	if (flags & SPI_XFER_BEGIN)
+		spi_cs_activate(regs, slave_plat->cs);
+
+	while (len > 0) {
+		int todo = min(len, 0xffff);
+
+		rkspi_enable_chip(regs, true);
+		writel(todo - 1, &regs->ctrlr1);
+		rkspi_enable_chip(regs, true);
+
+		toread = todo;
+		towrite = todo;
+		while (toread || towrite) {
+			u32 status = readl(&regs->sr);
+
+			if (towrite && !(status & SR_TF_FULL)) {
+				writel(out ? *out++ : 0, regs->txdr);
+				towrite--;
+			}
+			if (toread && !(status & SR_RF_EMPT)) {
+				u32 byte = readl(regs->rxdr);
+
+				if (in)
+					*in++ = byte;
+				toread--;
+			}
+		}
+		ret = rkspi_wait_till_not_busy(regs);
+		if (ret)
+			break;
+		len -= todo;
+	}
+
+	/* Deassert CS after transfer */
+	if (flags & SPI_XFER_END)
+		spi_cs_deactivate(regs, slave_plat->cs);
+
+	rkspi_enable_chip(regs, false);
+
+	return ret;
+}
+
+static int rockchip_spi_set_speed(struct udevice *bus, uint speed)
+{
+	struct rockchip_spi_priv *priv = dev_get_priv(bus);
+
+	if (speed > ROCKCHIP_SPI_MAX_RATE)
+		return -EINVAL;
+	if (speed > priv->max_freq)
+		speed = priv->max_freq;
+	priv->speed_hz = speed;
+
+	return 0;
+}
+
+static int rockchip_spi_set_mode(struct udevice *bus, uint mode)
+{
+	struct rockchip_spi_priv *priv = dev_get_priv(bus);
+
+	priv->mode = mode;
+
+	return 0;
+}
+
+static const struct dm_spi_ops rockchip_spi_ops = {
+	.claim_bus	= rockchip_spi_claim_bus,
+	.release_bus	= rockchip_spi_release_bus,
+	.xfer		= rockchip_spi_xfer,
+	.set_speed	= rockchip_spi_set_speed,
+	.set_mode	= rockchip_spi_set_mode,
+	/*
+	 * cs_info is not needed, since we require all chip selects to be
+	 * in the device tree explicitly
+	 */
+};
+
+static const struct udevice_id rockchip_spi_ids[] = {
+	{ .compatible = "rockchip,rk3288-spi" },
+	{ }
+};
+
+U_BOOT_DRIVER(rockchip_spi) = {
+	.name	= "rockchip_spi",
+	.id	= UCLASS_SPI,
+	.of_match = rockchip_spi_ids,
+	.ops	= &rockchip_spi_ops,
+	.ofdata_to_platdata = rockchip_spi_ofdata_to_platdata,
+	.platdata_auto_alloc_size = sizeof(struct rockchip_spi_platdata),
+	.priv_auto_alloc_size = sizeof(struct rockchip_spi_priv),
+	.probe	= rockchip_spi_probe,
+};

drivers/spi/rk_spi.h

@@ -0,0 +1,124 @@
+/*
+ * SPI driver for rockchip
+ *
+ * (C) Copyright 2015 Google, Inc
+ *
+ * (C) Copyright 2008-2013 Rockchip Electronics
+ * Peter, Software Engineering, <superpeter.cai@gmail.com>.
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#ifndef __RK_SPI_H
+#define __RK_SPI_H
+
+struct rockchip_spi {
+	u32 ctrlr0;
+	u32 ctrlr1;
+	u32 enr;
+	u32 ser;
+	u32 baudr;
+	u32 txftlr;
+	u32 rxftlr;
+	u32 txflr;
+	u32 rxflr;
+	u32 sr;
+	u32 ipr;
+	u32 imr;
+	u32 isr;
+	u32 risr;
+	u32 icr;
+	u32 dmacr;
+	u32 dmatdlr;
+	u32 dmardlr;		/* 0x44 */
+	u32 reserved[0xef];
+	u32 txdr[0x100];	/* 0x400 */
+	u32 rxdr[0x100];	/* 0x800 */
+};
+
+/* CTRLR0 */
+enum {
+	DFS_SHIFT	= 0,	/* Data Frame Size */
+	DFS_MASK	= 3,
+	DFS_4BIT	= 0,
+	DFS_8BIT,
+	DFS_16BIT,
+	DFS_RESV,
+
+	CFS_SHIFT	= 2,	/* Control Frame Size */
+	CFS_MASK	= 0xf,
+
+	SCPH_SHIFT	= 6,	/* Serial Clock Phase */
+	SCPH_MASK	= 1,
+	SCPH_TOGMID	= 0,	/* SCLK toggles in middle of first data bit */
+	SCPH_TOGSTA,		/* SCLK toggles at start of first data bit */
+
+	SCOL_SHIFT	= 7,	/* Serial Clock Polarity */
+	SCOL_MASK	= 1,
+	SCOL_LOW	= 0,	/* Inactive state of serial clock is low */
+	SCOL_HIGH,		/* Inactive state of serial clock is high */
+
+	CSM_SHIFT	= 8,	/* Chip Select Mode */
+	CSM_MASK	= 0x3,
+	CSM_KEEP	= 0,	/* ss_n stays low after each frame  */
+	CSM_HALF,		/* ss_n high for half sclk_out cycles */
+	CSM_ONE,		/* ss_n high for one sclk_out cycle */
+	CSM_RESV,
+
+	SSN_DELAY_SHIFT	= 10,	/* SSN to Sclk_out delay */
+	SSN_DELAY_MASK	= 1,
+	SSN_DELAY_HALF	= 0,	/* 1/2 sclk_out cycle */
+	SSN_DELAY_ONE	= 1,	/* 1 sclk_out cycle */
+
+	SEM_SHIFT	= 11,	/* Serial Endian Mode */
+	SEM_MASK	= 1,
+	SEM_LITTLE	= 0,	/* little endian */
+	SEM_BIG,		/* big endian */
+
+	FBM_SHIFT	= 12,	/* First Bit Mode */
+	FBM_MASK	= 1,
+	FBM_MSB		= 0,	/* first bit is MSB */
+	FBM_LSB,		/* first bit in LSB */
+
+	HALF_WORD_TX_SHIFT = 13,	/* Byte and Halfword Transform */
+	HALF_WORD_MASK	= 1,
+	HALF_WORD_ON	= 0,	/* apb 16bit write/read, spi 8bit write/read */
+	HALF_WORD_OFF,		/* apb 8bit write/read, spi 8bit write/read */
+
+	RXDSD_SHIFT	= 14,	/* Rxd Sample Delay, in cycles */
+	RXDSD_MASK	= 3,
+
+	FRF_SHIFT	= 16,	/* Frame Format */
+	FRF_MASK	= 3,
+	FRF_SPI		= 0,	/* Motorola SPI */
+	FRF_SSP,			/* Texas Instruments SSP*/
+	FRF_MICROWIRE,		/* National Semiconductors Microwire */
+	FRF_RESV,
+
+	TMOD_SHIFT	= 18,	/* Transfer Mode */
+	TMOD_MASK	= 3,
+	TMOD_TR		= 0,	/* xmit & recv */
+	TMOD_TO,		/* xmit only */
+	TMOD_RO,		/* recv only */
+	TMOD_RESV,
+
+	OMOD_SHIFT	= 20,	/* Operation Mode */
+	OMOD_MASK	= 1,
+	OMOD_MASTER	= 0,	/* Master Mode */
+	OMOD_SLAVE,		/* Slave Mode */
+};
+
+/* SR */
+enum {
+	SR_MASK		= 0x7f,
+	SR_BUSY		= 1 << 0,
+	SR_TF_FULL	= 1 << 1,
+	SR_TF_EMPT	= 1 << 2,
+	SR_RF_EMPT	= 1 << 3,
+	SR_RF_FULL	= 1 << 4,
+};
+
+#define ROCKCHIP_SPI_TIMEOUT_MS		1000
+#define ROCKCHIP_SPI_MAX_RATE		48000000
+
+#endif /* __RK_SPI_H */