[U-Boot,v2,2/4] sunxi: Add support for the rsb (Reduced Serial Bus)

diff --git a/arch/arm/cpu/armv7/sunxi/Makefile b/arch/arm/cpu/armv7/sunxi/Makefile
index 1337b60..3e8975a 100644
--- a/arch/arm/cpu/armv7/sunxi/Makefile
+++ b/arch/arm/cpu/armv7/sunxi/Makefile
@@ -15,6 +15,7 @@  obj-y	+= pinmux.o
 obj-$(CONFIG_MACH_SUN6I)	+= prcm.o
 obj-$(CONFIG_MACH_SUN8I)	+= prcm.o
 obj-$(CONFIG_MACH_SUN6I)	+= p2wi.o
+obj-$(CONFIG_MACH_SUN8I)	+= rsb.o
 obj-$(CONFIG_MACH_SUN4I)	+= clock_sun4i.o
 obj-$(CONFIG_MACH_SUN5I)	+= clock_sun4i.o
 obj-$(CONFIG_MACH_SUN6I)	+= clock_sun6i.o
diff --git a/arch/arm/cpu/armv7/sunxi/rsb.c b/arch/arm/cpu/armv7/sunxi/rsb.c
new file mode 100644
index 0000000..b72bb9d
--- /dev/null
+++ b/arch/arm/cpu/armv7/sunxi/rsb.c
@@ -0,0 +1,158 @@ 
+/*
+ * (C) Copyright 2014 Hans de Goede <hdegoede@redhat.com>
+ *
+ * Based on allwinner u-boot sources rsb code which is:
+ * (C) Copyright 2007-2013
+ * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
+ * lixiang <lixiang@allwinnertech.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/gpio.h>
+#include <asm/arch/prcm.h>
+#include <asm/arch/rsb.h>
+
+static void rsb_cfg_io(void)
+{
+	sunxi_gpio_set_cfgpin(SUNXI_GPL(0), SUN8I_GPL0_R_RSB_SCK);
+	sunxi_gpio_set_cfgpin(SUNXI_GPL(1), SUN8I_GPL1_R_RSB_SDA);
+	sunxi_gpio_set_pull(SUNXI_GPL(0), 1);
+	sunxi_gpio_set_pull(SUNXI_GPL(1), 1);
+	sunxi_gpio_set_drv(SUNXI_GPL(0), 2);
+	sunxi_gpio_set_drv(SUNXI_GPL(1), 2);
+}
+
+static void rsb_set_clk(void)
+{
+	struct sunxi_rsb_reg * const rsb =
+		(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
+	u32 div = 0;
+	u32 cd_odly = 0;
+
+	/* Source is Hosc24M, set RSB clk to 3Mhz */
+	div = 24000000 / 3000000 / 2 - 1;
+	cd_odly = div >> 1;
+	if (!cd_odly)
+		cd_odly = 1;
+
+	writel((cd_odly << 8) | div, &rsb->ccr);
+}
+
+void rsb_init(void)
+{
+	struct sunxi_rsb_reg * const rsb =
+		(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
+
+	rsb_cfg_io();
+
+	/* Enable RSB and PIO clk, and de-assert their resets */
+	prcm_apb0_enable(PRCM_APB0_GATE_PIO | PRCM_APB0_GATE_RSB);
+
+	writel(RSB_CTRL_SOFT_RST, &rsb->ctrl);
+	rsb_set_clk();
+}
+
+static int rsb_await_trans(void)
+{
+	struct sunxi_rsb_reg * const rsb =
+		(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
+	unsigned long tmo = timer_get_us() + 1000000;
+	u32 stat;
+	int ret;
+
+	while (1) {
+		stat = readl(&rsb->stat);
+		if (stat & RSB_STAT_LBSY_INT) {
+			ret = -EBUSY;
+			break;
+		}
+		if (stat & RSB_STAT_TERR_INT) {
+			ret = -EIO;
+			break;
+		}
+		if (stat & RSB_STAT_TOVER_INT) {
+			ret = 0;
+			break;
+		}
+		if (timer_get_us() > tmo) {
+			ret = -ETIME;
+			break;
+		}
+	}
+	writel(stat, &rsb->stat); /* Clear status bits */
+
+	return ret;
+}
+
+int rsb_set_device_mode(u32 device_mode_data)
+{
+	struct sunxi_rsb_reg * const rsb =
+		(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
+	unsigned long tmo = timer_get_us() + 1000000;
+
+	writel(RSB_DMCR_DEVICE_MODE_START | device_mode_data, &rsb->dmcr);
+
+	while (readl(&rsb->dmcr) & RSB_DMCR_DEVICE_MODE_START) {
+		if (timer_get_us() > tmo)
+			return -ETIME;
+	}
+
+	return rsb_await_trans();
+}
+
+static int rsb_do_trans(void)
+{
+	struct sunxi_rsb_reg * const rsb =
+		(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
+
+	setbits_le32(&rsb->ctrl, RSB_CTRL_START_TRANS);
+	return rsb_await_trans();
+}
+
+int rsb_set_device_address(u16 device_addr, u16 runtime_addr)
+{
+	struct sunxi_rsb_reg * const rsb =
+		(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
+
+	writel(RSB_DEVADDR_RUNTIME_ADDR(runtime_addr) |
+	       RSB_DEVADDR_DEVICE_ADDR(device_addr), &rsb->devaddr);
+	writel(RSB_CMD_SET_RTSADDR, &rsb->cmd);
+
+	return rsb_do_trans();
+}
+
+int rsb_write(const u16 runtime_device_addr, const u8 reg_addr, u8 data)
+{
+	struct sunxi_rsb_reg * const rsb =
+		(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
+
+	writel(RSB_DEVADDR_RUNTIME_ADDR(runtime_device_addr), &rsb->devaddr);
+	writel(reg_addr, &rsb->addr);
+	writel(data, &rsb->data);
+	writel(RSB_CMD_BYTE_WRITE, &rsb->cmd);
+
+	return rsb_do_trans();
+}
+
+int rsb_read(const u16 runtime_device_addr, const u8 reg_addr, u8 *data)
+{
+	struct sunxi_rsb_reg * const rsb =
+		(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
+	int ret;
+
+	writel(RSB_DEVADDR_RUNTIME_ADDR(runtime_device_addr), &rsb->devaddr);
+	writel(reg_addr, &rsb->addr);
+	writel(RSB_CMD_BYTE_READ, &rsb->cmd);
+
+	ret = rsb_do_trans();
+	if (ret)
+		return ret;
+
+	*data = readl(&rsb->data) & 0xff;
+
+	return 0;
+}
diff --git a/arch/arm/include/asm/arch-sunxi/cpu.h b/arch/arm/include/asm/arch-sunxi/cpu.h
index adf203a..bcfa00d 100644
--- a/arch/arm/include/asm/arch-sunxi/cpu.h
+++ b/arch/arm/include/asm/arch-sunxi/cpu.h
@@ -129,6 +129,7 @@ 
 #define SUNXI_R_UART_BASE		0x01f02800
 #define SUNXI_R_PIO_BASE		0x01f02c00
 #define SUN6I_P2WI_BASE			0x01f03400
+#define SUNXI_RSB_BASE			0x01f03400
 
 /* CoreSight Debug Module */
 #define SUNXI_CSDM_BASE			0x3f500000
diff --git a/arch/arm/include/asm/arch-sunxi/gpio.h b/arch/arm/include/asm/arch-sunxi/gpio.h
index 9f972ce..6623f15 100644
--- a/arch/arm/include/asm/arch-sunxi/gpio.h
+++ b/arch/arm/include/asm/arch-sunxi/gpio.h
@@ -176,6 +176,8 @@  enum sunxi_gpio_number {
 #define SUN6I_GPL0_R_P2WI_SCK	3
 #define SUN6I_GPL1_R_P2WI_SDA	3
 
+#define SUN8I_GPL0_R_RSB_SCK	2
+#define SUN8I_GPL1_R_RSB_SDA	2
 #define SUN8I_GPL2_R_UART_TX	2
 #define SUN8I_GPL3_R_UART_RX	2
 
diff --git a/arch/arm/include/asm/arch-sunxi/prcm.h b/arch/arm/include/asm/arch-sunxi/prcm.h
index 88de1ff..82ed541 100644
--- a/arch/arm/include/asm/arch-sunxi/prcm.h
+++ b/arch/arm/include/asm/arch-sunxi/prcm.h
@@ -50,7 +50,8 @@ 
 #define PRCM_APB0_GATE_PIO (0x1 << 0)
 #define PRCM_APB0_GATE_IR (0x1 << 1)
 #define PRCM_APB0_GATE_TIMER01 (0x1 << 2)
-#define PRCM_APB0_GATE_P2WI (0x1 << 3)
+#define PRCM_APB0_GATE_P2WI (0x1 << 3)		/* sun6i */
+#define PRCM_APB0_GATE_RSB (0x1 << 3)		/* sun8i */
 #define PRCM_APB0_GATE_UART (0x1 << 4)
 #define PRCM_APB0_GATE_1WIRE (0x1 << 5)
 #define PRCM_APB0_GATE_I2C (0x1 << 6)
diff --git a/arch/arm/include/asm/arch-sunxi/rsb.h b/arch/arm/include/asm/arch-sunxi/rsb.h
new file mode 100644
index 0000000..95a595a
--- /dev/null
+++ b/arch/arm/include/asm/arch-sunxi/rsb.h
@@ -0,0 +1,55 @@ 
+/*
+ * (C) Copyright 2014 Hans de Goede <hdegoede@redhat.com>
+ *
+ * Based on allwinner u-boot sources rsb code which is:
+ * (C) Copyright 2007-2013
+ * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
+ * lixiang <lixiang@allwinnertech.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __SUNXI_RSB_H
+#define __SUNXI_RSB_H
+
+#include <common.h>
+#include <asm/io.h>
+
+struct sunxi_rsb_reg {
+	u32 ctrl;	/* 0x00 */
+	u32 ccr;	/* 0x04 */
+	u32 inte;	/* 0x08 */
+	u32 stat;	/* 0x0c */
+	u32 addr;	/* 0x10 */
+	u8 res0[8];	/* 0x14 */
+	u32 data;	/* 0x1c */
+	u8 res1[4];	/* 0x20 */
+	u32 lcr;	/* 0x24 */
+	u32 dmcr;	/* 0x28 */
+	u32 cmd;	/* 0x2c */
+	u32 devaddr;	/* 0x30 */
+};
+
+#define RSB_CTRL_SOFT_RST		(1 << 0)
+#define RSB_CTRL_START_TRANS		(1 << 7)
+
+#define RSB_STAT_TOVER_INT		(1 << 0)
+#define RSB_STAT_TERR_INT		(1 << 1)
+#define RSB_STAT_LBSY_INT		(1 << 2)
+
+#define RSB_DMCR_DEVICE_MODE_START	(1 << 31)
+
+#define RSB_CMD_BYTE_WRITE		0x4e
+#define RSB_CMD_BYTE_READ		0x8b
+#define RSB_CMD_SET_RTSADDR		0xe8
+
+#define RSB_DEVADDR_RUNTIME_ADDR(x)	((x) << 16)
+#define RSB_DEVADDR_DEVICE_ADDR(x)	((x) << 0)
+
+void rsb_init(void);
+int rsb_set_device_mode(u32 device_mode_data);
+int rsb_set_device_address(u16 device_addr, u16 runtime_addr);
+int rsb_write(const u16 runtime_device_addr, const u8 reg_addr, u8 data);
+int rsb_read(const u16 runtime_device_addr, const u8 reg_addr, u8 *data);
+
+#endif