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 20 /* Serial registers - this driver works in uartdm mode*/ 21 22 #define UARTDM_DMRX 0x34 /* Max RX transfer length */ 23 #define UARTDM_NCF_TX 0x40 /* Number of chars to TX */ 24 25 #define UARTDM_RXFS 0x50 /* RX channel status register */ 26 #define UARTDM_RXFS_BUF_SHIFT 0x7 /* Number of bytes in the packing buffer */ 27 #define UARTDM_RXFS_BUF_MASK 0x7 28 29 #define UARTDM_SR 0xA4 /* Status register */ 30 #define UARTDM_SR_RX_READY (1 << 0) /* Word is the receiver FIFO */ 31 #define UARTDM_SR_TX_EMPTY (1 << 3) /* Transmitter underrun */ 32 #define UARTDM_SR_UART_OVERRUN (1 << 4) /* Receive overrun */ 33 34 #define UARTDM_CR 0xA8 /* Command register */ 35 #define UARTDM_CR_CMD_RESET_ERR (3 << 4) /* Clear overrun error */ 36 #define UARTDM_CR_CMD_RESET_STALE_INT (8 << 4) /* Clears stale irq */ 37 #define UARTDM_CR_CMD_RESET_TX_READY (3 << 8) /* Clears TX Ready irq*/ 38 #define UARTDM_CR_CMD_FORCE_STALE (4 << 8) /* Causes stale event */ 39 #define UARTDM_CR_CMD_STALE_EVENT_DISABLE (6 << 8) /* Disable stale event */ 40 41 #define UARTDM_IMR 0xB0 /* Interrupt mask register */ 42 #define UARTDM_ISR 0xB4 /* Interrupt status register */ 43 #define UARTDM_ISR_TX_READY 0x80 /* TX FIFO empty */ 44 45 #define UARTDM_TF 0x100 /* UART Transmit FIFO register */ 46 #define UARTDM_RF 0x140 /* UART Receive FIFO register */ 47 48 49 DECLARE_GLOBAL_DATA_PTR; 50 51 struct msm_serial_data { 52 phys_addr_t base; 53 unsigned chars_cnt; /* number of buffered chars */ 54 uint32_t chars_buf; /* buffered chars */ 55 }; 56 57 static int msm_serial_fetch(struct udevice *dev) 58 { 59 struct msm_serial_data *priv = dev_get_priv(dev); 60 unsigned sr; 61 62 if (priv->chars_cnt) 63 return priv->chars_cnt; 64 65 /* Clear error in case of buffer overrun */ 66 if (readl(priv->base + UARTDM_SR) & UARTDM_SR_UART_OVERRUN) 67 writel(UARTDM_CR_CMD_RESET_ERR, priv->base + UARTDM_CR); 68 69 /* We need to fetch new character */ 70 sr = readl(priv->base + UARTDM_SR); 71 72 if (sr & UARTDM_SR_RX_READY) { 73 /* There are at least 4 bytes in fifo */ 74 priv->chars_buf = readl(priv->base + UARTDM_RF); 75 priv->chars_cnt = 4; 76 } else { 77 /* Check if there is anything in fifo */ 78 priv->chars_cnt = readl(priv->base + UARTDM_RXFS); 79 /* Extract number of characters in UART packing buffer*/ 80 priv->chars_cnt = (priv->chars_cnt >> 81 UARTDM_RXFS_BUF_SHIFT) & 82 UARTDM_RXFS_BUF_MASK; 83 if (!priv->chars_cnt) 84 return 0; 85 86 /* There is at least one charcter, move it to fifo */ 87 writel(UARTDM_CR_CMD_FORCE_STALE, 88 priv->base + UARTDM_CR); 89 90 priv->chars_buf = readl(priv->base + UARTDM_RF); 91 writel(UARTDM_CR_CMD_RESET_STALE_INT, 92 priv->base + UARTDM_CR); 93 writel(0x7, priv->base + UARTDM_DMRX); 94 } 95 96 return priv->chars_cnt; 97 } 98 99 static int msm_serial_getc(struct udevice *dev) 100 { 101 struct msm_serial_data *priv = dev_get_priv(dev); 102 char c; 103 104 if (!msm_serial_fetch(dev)) 105 return -EAGAIN; 106 107 c = priv->chars_buf & 0xFF; 108 priv->chars_buf >>= 8; 109 priv->chars_cnt--; 110 111 return c; 112 } 113 114 static int msm_serial_putc(struct udevice *dev, const char ch) 115 { 116 struct msm_serial_data *priv = dev_get_priv(dev); 117 118 if (!(readl(priv->base + UARTDM_SR) & UARTDM_SR_TX_EMPTY) && 119 !(readl(priv->base + UARTDM_ISR) & UARTDM_ISR_TX_READY)) 120 return -EAGAIN; 121 122 writel(UARTDM_CR_CMD_RESET_TX_READY, priv->base + UARTDM_CR); 123 124 writel(1, priv->base + UARTDM_NCF_TX); 125 writel(ch, priv->base + UARTDM_TF); 126 127 return 0; 128 } 129 130 static int msm_serial_pending(struct udevice *dev, bool input) 131 { 132 if (input) { 133 if (msm_serial_fetch(dev)) 134 return 1; 135 } 136 137 return 0; 138 } 139 140 static const struct dm_serial_ops msm_serial_ops = { 141 .putc = msm_serial_putc, 142 .pending = msm_serial_pending, 143 .getc = msm_serial_getc, 144 }; 145 146 static int msm_uart_clk_init(struct udevice *dev) 147 { 148 uint clk_rate = fdtdec_get_uint(gd->fdt_blob, dev_of_offset(dev), 149 "clock-frequency", 115200); 150 uint clkd[2]; /* clk_id and clk_no */ 151 int clk_offset; 152 struct udevice *clk_dev; 153 struct clk clk; 154 int ret; 155 156 ret = fdtdec_get_int_array(gd->fdt_blob, dev_of_offset(dev), "clock", 157 clkd, 2); 158 if (ret) 159 return ret; 160 161 clk_offset = fdt_node_offset_by_phandle(gd->fdt_blob, clkd[0]); 162 if (clk_offset < 0) 163 return clk_offset; 164 165 ret = uclass_get_device_by_of_offset(UCLASS_CLK, clk_offset, &clk_dev); 166 if (ret) 167 return ret; 168 169 clk.id = clkd[1]; 170 ret = clk_request(clk_dev, &clk); 171 if (ret < 0) 172 return ret; 173 174 ret = clk_set_rate(&clk, clk_rate); 175 clk_free(&clk); 176 if (ret < 0) 177 return ret; 178 179 return 0; 180 } 181 182 static int msm_serial_probe(struct udevice *dev) 183 { 184 struct msm_serial_data *priv = dev_get_priv(dev); 185 186 msm_uart_clk_init(dev); /* Ignore return value and hope clock was 187 properly initialized by earlier loaders */ 188 189 if (readl(priv->base + UARTDM_SR) & UARTDM_SR_UART_OVERRUN) 190 writel(UARTDM_CR_CMD_RESET_ERR, priv->base + UARTDM_CR); 191 192 writel(0, priv->base + UARTDM_IMR); 193 writel(UARTDM_CR_CMD_STALE_EVENT_DISABLE, priv->base + UARTDM_CR); 194 msm_serial_fetch(dev); 195 196 return 0; 197 } 198 199 static int msm_serial_ofdata_to_platdata(struct udevice *dev) 200 { 201 struct msm_serial_data *priv = dev_get_priv(dev); 202 203 priv->base = devfdt_get_addr(dev); 204 if (priv->base == FDT_ADDR_T_NONE) 205 return -EINVAL; 206 207 return 0; 208 } 209 210 static const struct udevice_id msm_serial_ids[] = { 211 { .compatible = "qcom,msm-uartdm-v1.4" }, 212 { } 213 }; 214 215 U_BOOT_DRIVER(serial_msm) = { 216 .name = "serial_msm", 217 .id = UCLASS_SERIAL, 218 .of_match = msm_serial_ids, 219 .ofdata_to_platdata = msm_serial_ofdata_to_platdata, 220 .priv_auto_alloc_size = sizeof(struct msm_serial_data), 221 .probe = msm_serial_probe, 222 .ops = &msm_serial_ops, 223 }; 224