1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Qualcomm UART driver 4 * 5 * (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com> 6 * 7 * UART will work in Data Mover mode. 8 * Based on Linux driver. 9 */ 10 11 #include <common.h> 12 #include <clk.h> 13 #include <dm.h> 14 #include <errno.h> 15 #include <serial.h> 16 #include <watchdog.h> 17 #include <asm/io.h> 18 #include <linux/compiler.h> 19 #include <dm/pinctrl.h> 20 21 /* Serial registers - this driver works in uartdm mode*/ 22 23 #define UARTDM_DMRX 0x34 /* Max RX transfer length */ 24 #define UARTDM_NCF_TX 0x40 /* Number of chars to TX */ 25 26 #define UARTDM_RXFS 0x50 /* RX channel status register */ 27 #define UARTDM_RXFS_BUF_SHIFT 0x7 /* Number of bytes in the packing buffer */ 28 #define UARTDM_RXFS_BUF_MASK 0x7 29 #define UARTDM_MR1 0x00 30 #define UARTDM_MR2 0x04 31 #define UARTDM_CSR 0xA0 32 33 #define UARTDM_SR 0xA4 /* Status register */ 34 #define UARTDM_SR_RX_READY (1 << 0) /* Word is the receiver FIFO */ 35 #define UARTDM_SR_TX_EMPTY (1 << 3) /* Transmitter underrun */ 36 #define UARTDM_SR_UART_OVERRUN (1 << 4) /* Receive overrun */ 37 38 #define UARTDM_CR 0xA8 /* Command register */ 39 #define UARTDM_CR_CMD_RESET_ERR (3 << 4) /* Clear overrun error */ 40 #define UARTDM_CR_CMD_RESET_STALE_INT (8 << 4) /* Clears stale irq */ 41 #define UARTDM_CR_CMD_RESET_TX_READY (3 << 8) /* Clears TX Ready irq*/ 42 #define UARTDM_CR_CMD_FORCE_STALE (4 << 8) /* Causes stale event */ 43 #define UARTDM_CR_CMD_STALE_EVENT_DISABLE (6 << 8) /* Disable stale event */ 44 45 #define UARTDM_IMR 0xB0 /* Interrupt mask register */ 46 #define UARTDM_ISR 0xB4 /* Interrupt status register */ 47 #define UARTDM_ISR_TX_READY 0x80 /* TX FIFO empty */ 48 49 #define UARTDM_TF 0x100 /* UART Transmit FIFO register */ 50 #define UARTDM_RF 0x140 /* UART Receive FIFO register */ 51 52 #define UART_DM_CLK_RX_TX_BIT_RATE 0xCC 53 #define MSM_BOOT_UART_DM_8_N_1_MODE 0x34 54 #define MSM_BOOT_UART_DM_CMD_RESET_RX 0x10 55 #define MSM_BOOT_UART_DM_CMD_RESET_TX 0x20 56 57 DECLARE_GLOBAL_DATA_PTR; 58 59 struct msm_serial_data { 60 phys_addr_t base; 61 unsigned chars_cnt; /* number of buffered chars */ 62 uint32_t chars_buf; /* buffered chars */ 63 }; 64 65 static int msm_serial_fetch(struct udevice *dev) 66 { 67 struct msm_serial_data *priv = dev_get_priv(dev); 68 unsigned sr; 69 70 if (priv->chars_cnt) 71 return priv->chars_cnt; 72 73 /* Clear error in case of buffer overrun */ 74 if (readl(priv->base + UARTDM_SR) & UARTDM_SR_UART_OVERRUN) 75 writel(UARTDM_CR_CMD_RESET_ERR, priv->base + UARTDM_CR); 76 77 /* We need to fetch new character */ 78 sr = readl(priv->base + UARTDM_SR); 79 80 if (sr & UARTDM_SR_RX_READY) { 81 /* There are at least 4 bytes in fifo */ 82 priv->chars_buf = readl(priv->base + UARTDM_RF); 83 priv->chars_cnt = 4; 84 } else { 85 /* Check if there is anything in fifo */ 86 priv->chars_cnt = readl(priv->base + UARTDM_RXFS); 87 /* Extract number of characters in UART packing buffer*/ 88 priv->chars_cnt = (priv->chars_cnt >> 89 UARTDM_RXFS_BUF_SHIFT) & 90 UARTDM_RXFS_BUF_MASK; 91 if (!priv->chars_cnt) 92 return 0; 93 94 /* There is at least one charcter, move it to fifo */ 95 writel(UARTDM_CR_CMD_FORCE_STALE, 96 priv->base + UARTDM_CR); 97 98 priv->chars_buf = readl(priv->base + UARTDM_RF); 99 writel(UARTDM_CR_CMD_RESET_STALE_INT, 100 priv->base + UARTDM_CR); 101 writel(0x7, priv->base + UARTDM_DMRX); 102 } 103 104 return priv->chars_cnt; 105 } 106 107 static int msm_serial_getc(struct udevice *dev) 108 { 109 struct msm_serial_data *priv = dev_get_priv(dev); 110 char c; 111 112 if (!msm_serial_fetch(dev)) 113 return -EAGAIN; 114 115 c = priv->chars_buf & 0xFF; 116 priv->chars_buf >>= 8; 117 priv->chars_cnt--; 118 119 return c; 120 } 121 122 static int msm_serial_putc(struct udevice *dev, const char ch) 123 { 124 struct msm_serial_data *priv = dev_get_priv(dev); 125 126 if (!(readl(priv->base + UARTDM_SR) & UARTDM_SR_TX_EMPTY) && 127 !(readl(priv->base + UARTDM_ISR) & UARTDM_ISR_TX_READY)) 128 return -EAGAIN; 129 130 writel(UARTDM_CR_CMD_RESET_TX_READY, priv->base + UARTDM_CR); 131 132 writel(1, priv->base + UARTDM_NCF_TX); 133 writel(ch, priv->base + UARTDM_TF); 134 135 return 0; 136 } 137 138 static int msm_serial_pending(struct udevice *dev, bool input) 139 { 140 if (input) { 141 if (msm_serial_fetch(dev)) 142 return 1; 143 } 144 145 return 0; 146 } 147 148 static const struct dm_serial_ops msm_serial_ops = { 149 .putc = msm_serial_putc, 150 .pending = msm_serial_pending, 151 .getc = msm_serial_getc, 152 }; 153 154 static int msm_uart_clk_init(struct udevice *dev) 155 { 156 uint clk_rate = fdtdec_get_uint(gd->fdt_blob, dev_of_offset(dev), 157 "clock-frequency", 115200); 158 uint clkd[2]; /* clk_id and clk_no */ 159 int clk_offset; 160 struct udevice *clk_dev; 161 struct clk clk; 162 int ret; 163 164 ret = fdtdec_get_int_array(gd->fdt_blob, dev_of_offset(dev), "clock", 165 clkd, 2); 166 if (ret) 167 return ret; 168 169 clk_offset = fdt_node_offset_by_phandle(gd->fdt_blob, clkd[0]); 170 if (clk_offset < 0) 171 return clk_offset; 172 173 ret = uclass_get_device_by_of_offset(UCLASS_CLK, clk_offset, &clk_dev); 174 if (ret) 175 return ret; 176 177 clk.id = clkd[1]; 178 ret = clk_request(clk_dev, &clk); 179 if (ret < 0) 180 return ret; 181 182 ret = clk_set_rate(&clk, clk_rate); 183 clk_free(&clk); 184 if (ret < 0) 185 return ret; 186 187 return 0; 188 } 189 190 static void uart_dm_init(struct msm_serial_data *priv) 191 { 192 writel(UART_DM_CLK_RX_TX_BIT_RATE, priv->base + UARTDM_CSR); 193 writel(0x0, priv->base + UARTDM_MR1); 194 writel(MSM_BOOT_UART_DM_8_N_1_MODE, priv->base + UARTDM_MR2); 195 writel(MSM_BOOT_UART_DM_CMD_RESET_RX, priv->base + UARTDM_CR); 196 writel(MSM_BOOT_UART_DM_CMD_RESET_TX, priv->base + UARTDM_CR); 197 } 198 static int msm_serial_probe(struct udevice *dev) 199 { 200 int ret; 201 struct msm_serial_data *priv = dev_get_priv(dev); 202 203 /* No need to reinitialize the UART after relocation */ 204 if (gd->flags & GD_FLG_RELOC) 205 return 0; 206 207 ret = msm_uart_clk_init(dev); 208 if (ret) 209 return ret; 210 211 pinctrl_select_state(dev, "uart"); 212 uart_dm_init(priv); 213 214 return 0; 215 } 216 217 static int msm_serial_ofdata_to_platdata(struct udevice *dev) 218 { 219 struct msm_serial_data *priv = dev_get_priv(dev); 220 221 priv->base = devfdt_get_addr(dev); 222 if (priv->base == FDT_ADDR_T_NONE) 223 return -EINVAL; 224 225 return 0; 226 } 227 228 static const struct udevice_id msm_serial_ids[] = { 229 { .compatible = "qcom,msm-uartdm-v1.4" }, 230 { } 231 }; 232 233 U_BOOT_DRIVER(serial_msm) = { 234 .name = "serial_msm", 235 .id = UCLASS_SERIAL, 236 .of_match = msm_serial_ids, 237 .ofdata_to_platdata = msm_serial_ofdata_to_platdata, 238 .priv_auto_alloc_size = sizeof(struct msm_serial_data), 239 .probe = msm_serial_probe, 240 .ops = &msm_serial_ops, 241 }; 242