git.sur5r.net Git - u-boot/blob - arch/arm/mach-sunxi/rsb.c

   1 /*
   2  * (C) Copyright 2014 Hans de Goede <hdegoede@redhat.com>
   3  *
   4  * Based on allwinner u-boot sources rsb code which is:
   5  * (C) Copyright 2007-2013
   6  * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
   7  * lixiang <lixiang@allwinnertech.com>
   8  *
   9  * SPDX-License-Identifier:     GPL-2.0+
  10  */
  11
  12 #include <common.h>
  13 #include <errno.h>
  14 #include <asm/arch/cpu.h>
  15 #include <asm/arch/gpio.h>
  16 #include <asm/arch/prcm.h>
  17 #include <asm/arch/rsb.h>
  18
  19 static int rsb_set_device_mode(void);
  20
  21 static void rsb_cfg_io(void)
  22 {
  23 #ifdef CONFIG_MACH_SUN8I
  24         sunxi_gpio_set_cfgpin(SUNXI_GPL(0), SUN8I_GPL_R_RSB);
  25         sunxi_gpio_set_cfgpin(SUNXI_GPL(1), SUN8I_GPL_R_RSB);
  26         sunxi_gpio_set_pull(SUNXI_GPL(0), 1);
  27         sunxi_gpio_set_pull(SUNXI_GPL(1), 1);
  28         sunxi_gpio_set_drv(SUNXI_GPL(0), 2);
  29         sunxi_gpio_set_drv(SUNXI_GPL(1), 2);
  30 #elif defined CONFIG_MACH_SUN9I
  31         sunxi_gpio_set_cfgpin(SUNXI_GPN(0), SUN9I_GPN_R_RSB);
  32         sunxi_gpio_set_cfgpin(SUNXI_GPN(1), SUN9I_GPN_R_RSB);
  33         sunxi_gpio_set_pull(SUNXI_GPN(0), 1);
  34         sunxi_gpio_set_pull(SUNXI_GPN(1), 1);
  35         sunxi_gpio_set_drv(SUNXI_GPN(0), 2);
  36         sunxi_gpio_set_drv(SUNXI_GPN(1), 2);
  37 #else
  38 #error unsupported MACH_SUNXI
  39 #endif
  40 }
  41
  42 static void rsb_set_clk(void)
  43 {
  44         struct sunxi_rsb_reg * const rsb =
  45                 (struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
  46         u32 div = 0;
  47         u32 cd_odly = 0;
  48
  49         /* Source is Hosc24M, set RSB clk to 3Mhz */
  50         div = 24000000 / 3000000 / 2 - 1;
  51         cd_odly = div >> 1;
  52         if (!cd_odly)
  53                 cd_odly = 1;
  54
  55         writel((cd_odly << 8) | div, &rsb->ccr);
  56 }
  57
  58 int rsb_init(void)
  59 {
  60         struct sunxi_rsb_reg * const rsb =
  61                 (struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
  62
  63         /* Enable RSB and PIO clk, and de-assert their resets */
  64         prcm_apb0_enable(PRCM_APB0_GATE_PIO | PRCM_APB0_GATE_RSB);
  65
  66         /* Setup external pins */
  67         rsb_cfg_io();
  68
  69         writel(RSB_CTRL_SOFT_RST, &rsb->ctrl);
  70         rsb_set_clk();
  71
  72         return rsb_set_device_mode();
  73 }
  74
  75 static int rsb_await_trans(void)
  76 {
  77         struct sunxi_rsb_reg * const rsb =
  78                 (struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
  79         unsigned long tmo = timer_get_us() + 1000000;
  80         u32 stat;
  81         int ret;
  82
  83         while (1) {
  84                 stat = readl(&rsb->stat);
  85                 if (stat & RSB_STAT_LBSY_INT) {
  86                         ret = -EBUSY;
  87                         break;
  88                 }
  89                 if (stat & RSB_STAT_TERR_INT) {
  90                         ret = -EIO;
  91                         break;
  92                 }
  93                 if (stat & RSB_STAT_TOVER_INT) {
  94                         ret = 0;
  95                         break;
  96                 }
  97                 if (timer_get_us() > tmo) {
  98                         ret = -ETIME;
  99                         break;
 100                 }
 101         }
 102         writel(stat, &rsb->stat); /* Clear status bits */
 103
 104         return ret;
 105 }
 106
 107 static int rsb_set_device_mode(void)
 108 {
 109         struct sunxi_rsb_reg * const rsb =
 110                 (struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
 111         unsigned long tmo = timer_get_us() + 1000000;
 112
 113         writel(RSB_DMCR_DEVICE_MODE_START | RSB_DMCR_DEVICE_MODE_DATA,
 114                &rsb->dmcr);
 115
 116         while (readl(&rsb->dmcr) & RSB_DMCR_DEVICE_MODE_START) {
 117                 if (timer_get_us() > tmo)
 118                         return -ETIME;
 119         }
 120
 121         return rsb_await_trans();
 122 }
 123
 124 static int rsb_do_trans(void)
 125 {
 126         struct sunxi_rsb_reg * const rsb =
 127                 (struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
 128
 129         setbits_le32(&rsb->ctrl, RSB_CTRL_START_TRANS);
 130         return rsb_await_trans();
 131 }
 132
 133 int rsb_set_device_address(u16 device_addr, u16 runtime_addr)
 134 {
 135         struct sunxi_rsb_reg * const rsb =
 136                 (struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
 137
 138         writel(RSB_DEVADDR_RUNTIME_ADDR(runtime_addr) |
 139                RSB_DEVADDR_DEVICE_ADDR(device_addr), &rsb->devaddr);
 140         writel(RSB_CMD_SET_RTSADDR, &rsb->cmd);
 141
 142         return rsb_do_trans();
 143 }
 144
 145 int rsb_write(const u16 runtime_device_addr, const u8 reg_addr, u8 data)
 146 {
 147         struct sunxi_rsb_reg * const rsb =
 148                 (struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
 149
 150         writel(RSB_DEVADDR_RUNTIME_ADDR(runtime_device_addr), &rsb->devaddr);
 151         writel(reg_addr, &rsb->addr);
 152         writel(data, &rsb->data);
 153         writel(RSB_CMD_BYTE_WRITE, &rsb->cmd);
 154
 155         return rsb_do_trans();
 156 }
 157
 158 int rsb_read(const u16 runtime_device_addr, const u8 reg_addr, u8 *data)
 159 {
 160         struct sunxi_rsb_reg * const rsb =
 161                 (struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
 162         int ret;
 163
 164         writel(RSB_DEVADDR_RUNTIME_ADDR(runtime_device_addr), &rsb->devaddr);
 165         writel(reg_addr, &rsb->addr);
 166         writel(RSB_CMD_BYTE_READ, &rsb->cmd);
 167
 168         ret = rsb_do_trans();
 169         if (ret)
 170                 return ret;
 171
 172         *data = readl(&rsb->data) & 0xff;
 173
 174         return 0;
 175 }