drivers/serial/serial_s5p.c

   1 /*
   2  * (C) Copyright 2009 SAMSUNG Electronics
   3  * Minkyu Kang <mk7.kang@samsung.com>
   4  * Heungjun Kim <riverful.kim@samsung.com>
   5  *
   6  * based on drivers/serial/s3c64xx.c
   7  *
   8  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11 #include <common.h>
  12 #include <dm.h>
  13 #include <errno.h>
  14 #include <fdtdec.h>
  15 #include <linux/compiler.h>
  16 #include <asm/io.h>
  17 #include <asm/arch/clk.h>
  18 #include <asm/arch/uart.h>
  19 #include <serial.h>
  20 #include <clk.h>
  21
  22 DECLARE_GLOBAL_DATA_PTR;
  23
  24 #define RX_FIFO_COUNT_SHIFT     0
  25 #define RX_FIFO_COUNT_MASK      (0xff << RX_FIFO_COUNT_SHIFT)
  26 #define RX_FIFO_FULL            (1 << 8)
  27 #define TX_FIFO_COUNT_SHIFT     16
  28 #define TX_FIFO_COUNT_MASK      (0xff << TX_FIFO_COUNT_SHIFT)
  29 #define TX_FIFO_FULL            (1 << 24)
  30
  31 /* Information about a serial port */
  32 struct s5p_serial_platdata {
  33         struct s5p_uart *reg;  /* address of registers in physical memory */
  34         u8 port_id;     /* uart port number */
  35 };
  36
  37 /*
  38  * The coefficient, used to calculate the baudrate on S5P UARTs is
  39  * calculated as
  40  * C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT
  41  * however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1,
  42  * 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants:
  43  */
  44 static const int udivslot[] = {
  45         0,
  46         0x0080,
  47         0x0808,
  48         0x0888,
  49         0x2222,
  50         0x4924,
  51         0x4a52,
  52         0x54aa,
  53         0x5555,
  54         0xd555,
  55         0xd5d5,
  56         0xddd5,
  57         0xdddd,
  58         0xdfdd,
  59         0xdfdf,
  60         0xffdf,
  61 };
  62
  63 static void __maybe_unused s5p_serial_init(struct s5p_uart *uart)
  64 {
  65         /* enable FIFOs, auto clear Rx FIFO */
  66         writel(0x3, &uart->ufcon);
  67         writel(0, &uart->umcon);
  68         /* 8N1 */
  69         writel(0x3, &uart->ulcon);
  70         /* No interrupts, no DMA, pure polling */
  71         writel(0x245, &uart->ucon);
  72 }
  73
  74 static void __maybe_unused s5p_serial_baud(struct s5p_uart *uart, uint uclk,
  75                                            int baudrate)
  76 {
  77         u32 val;
  78
  79         val = uclk / baudrate;
  80
  81         writel(val / 16 - 1, &uart->ubrdiv);
  82
  83         if (s5p_uart_divslot())
  84                 writew(udivslot[val % 16], &uart->rest.slot);
  85         else
  86                 writeb(val % 16, &uart->rest.value);
  87 }
  88
  89 #ifndef CONFIG_SPL_BUILD
  90 int s5p_serial_setbrg(struct udevice *dev, int baudrate)
  91 {
  92         struct s5p_serial_platdata *plat = dev->platdata;
  93         struct s5p_uart *const uart = plat->reg;
  94         u32 uclk;
  95
  96 #ifdef CONFIG_CLK_EXYNOS
  97         struct clk clk;
  98         u32 ret;
  99
 100         ret = clk_get_by_index(dev, 1, &clk);
 101         if (ret < 0)
 102                 return ret;
 103         uclk = clk_get_rate(&clk);
 104 #else
 105         uclk = get_uart_clk(plat->port_id);
 106 #endif
 107
 108         s5p_serial_baud(uart, uclk, baudrate);
 109
 110         return 0;
 111 }
 112
 113 static int s5p_serial_probe(struct udevice *dev)
 114 {
 115         struct s5p_serial_platdata *plat = dev->platdata;
 116         struct s5p_uart *const uart = plat->reg;
 117
 118         s5p_serial_init(uart);
 119
 120         return 0;
 121 }
 122
 123 static int serial_err_check(const struct s5p_uart *const uart, int op)
 124 {
 125         unsigned int mask;
 126
 127         /*
 128          * UERSTAT
 129          * Break Detect [3]
 130          * Frame Err    [2] : receive operation
 131          * Parity Err   [1] : receive operation
 132          * Overrun Err  [0] : receive operation
 133          */
 134         if (op)
 135                 mask = 0x8;
 136         else
 137                 mask = 0xf;
 138
 139         return readl(&uart->uerstat) & mask;
 140 }
 141
 142 static int s5p_serial_getc(struct udevice *dev)
 143 {
 144         struct s5p_serial_platdata *plat = dev->platdata;
 145         struct s5p_uart *const uart = plat->reg;
 146
 147         if (!(readl(&uart->ufstat) & RX_FIFO_COUNT_MASK))
 148                 return -EAGAIN;
 149
 150         serial_err_check(uart, 0);
 151         return (int)(readb(&uart->urxh) & 0xff);
 152 }
 153
 154 static int s5p_serial_putc(struct udevice *dev, const char ch)
 155 {
 156         struct s5p_serial_platdata *plat = dev->platdata;
 157         struct s5p_uart *const uart = plat->reg;
 158
 159         if (readl(&uart->ufstat) & TX_FIFO_FULL)
 160                 return -EAGAIN;
 161
 162         writeb(ch, &uart->utxh);
 163         serial_err_check(uart, 1);
 164
 165         return 0;
 166 }
 167
 168 static int s5p_serial_pending(struct udevice *dev, bool input)
 169 {
 170         struct s5p_serial_platdata *plat = dev->platdata;
 171         struct s5p_uart *const uart = plat->reg;
 172         uint32_t ufstat = readl(&uart->ufstat);
 173
 174         if (input)
 175                 return (ufstat & RX_FIFO_COUNT_MASK) >> RX_FIFO_COUNT_SHIFT;
 176         else
 177                 return (ufstat & TX_FIFO_COUNT_MASK) >> TX_FIFO_COUNT_SHIFT;
 178 }
 179
 180 static int s5p_serial_ofdata_to_platdata(struct udevice *dev)
 181 {
 182         struct s5p_serial_platdata *plat = dev->platdata;
 183         fdt_addr_t addr;
 184
 185         addr = dev_get_addr(dev);
 186         if (addr == FDT_ADDR_T_NONE)
 187                 return -EINVAL;
 188
 189         plat->reg = (struct s5p_uart *)addr;
 190         plat->port_id = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
 191                                         "id", dev->seq);
 192         return 0;
 193 }
 194
 195 static const struct dm_serial_ops s5p_serial_ops = {
 196         .putc = s5p_serial_putc,
 197         .pending = s5p_serial_pending,
 198         .getc = s5p_serial_getc,
 199         .setbrg = s5p_serial_setbrg,
 200 };
 201
 202 static const struct udevice_id s5p_serial_ids[] = {
 203         { .compatible = "samsung,exynos4210-uart" },
 204         { }
 205 };
 206
 207 U_BOOT_DRIVER(serial_s5p) = {
 208         .name   = "serial_s5p",
 209         .id     = UCLASS_SERIAL,
 210         .of_match = s5p_serial_ids,
 211         .ofdata_to_platdata = s5p_serial_ofdata_to_platdata,
 212         .platdata_auto_alloc_size = sizeof(struct s5p_serial_platdata),
 213         .probe = s5p_serial_probe,
 214         .ops    = &s5p_serial_ops,
 215         .flags = DM_FLAG_PRE_RELOC,
 216 };
 217 #endif
 218
 219 #ifdef CONFIG_DEBUG_UART_S5P
 220
 221 #include <debug_uart.h>
 222
 223 static inline void _debug_uart_init(void)
 224 {
 225         struct s5p_uart *uart = (struct s5p_uart *)CONFIG_DEBUG_UART_BASE;
 226
 227         s5p_serial_init(uart);
 228         s5p_serial_baud(uart, CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
 229 }
 230
 231 static inline void _debug_uart_putc(int ch)
 232 {
 233         struct s5p_uart *uart = (struct s5p_uart *)CONFIG_DEBUG_UART_BASE;
 234
 235         while (readl(&uart->ufstat) & TX_FIFO_FULL);
 236
 237         writeb(ch, &uart->utxh);
 238 }
 239
 240 DEBUG_UART_FUNCS
 241
 242 #endif