drivers/serial/serial_uniphier.c

   1 /*
   2  * Copyright (C) 2012-2014 Panasonic Corporation
   3  *   Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <linux/serial_reg.h>
   9 #include <asm/io.h>
  10 #include <asm/errno.h>
  11 #include <dm/device.h>
  12 #include <dm/platform_data/serial-uniphier.h>
  13 #include <serial.h>
  14 #include <fdtdec.h>
  15
  16 #define UART_REG(x)                                     \
  17         u8 x;                                           \
  18         u8 postpad_##x[3];
  19
  20 /*
  21  * Note: Register map is slightly different from that of 16550.
  22  */
  23 struct uniphier_serial {
  24         UART_REG(rbr);          /* 0x00 */
  25         UART_REG(ier);          /* 0x04 */
  26         UART_REG(iir);          /* 0x08 */
  27         UART_REG(fcr);          /* 0x0c */
  28         u8 mcr;                 /* 0x10 */
  29         u8 lcr;
  30         u16 __postpad;
  31         UART_REG(lsr);          /* 0x14 */
  32         UART_REG(msr);          /* 0x18 */
  33         u32 __none1;
  34         u32 __none2;
  35         u16 dlr;
  36         u16 __postpad2;
  37 };
  38
  39 #define thr rbr
  40
  41 struct uniphier_serial_private_data {
  42         struct uniphier_serial __iomem *membase;
  43 };
  44
  45 #define uniphier_serial_port(dev)       \
  46         ((struct uniphier_serial_private_data *)dev_get_priv(dev))->membase
  47
  48 static int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
  49 {
  50         struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
  51         struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  52         const unsigned int mode_x_div = 16;
  53         unsigned int divisor;
  54
  55         writeb(UART_LCR_WLEN8, &port->lcr);
  56
  57         divisor = DIV_ROUND_CLOSEST(plat->uartclk, mode_x_div * baudrate);
  58
  59         writew(divisor, &port->dlr);
  60
  61         return 0;
  62 }
  63
  64 static int uniphier_serial_getc(struct udevice *dev)
  65 {
  66         struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  67
  68         if (!(readb(&port->lsr) & UART_LSR_DR))
  69                 return -EAGAIN;
  70
  71         return readb(&port->rbr);
  72 }
  73
  74 static int uniphier_serial_putc(struct udevice *dev, const char c)
  75 {
  76         struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  77
  78         if (!(readb(&port->lsr) & UART_LSR_THRE))
  79                 return -EAGAIN;
  80
  81         writeb(c, &port->thr);
  82
  83         return 0;
  84 }
  85
  86 static int uniphier_serial_pending(struct udevice *dev, bool input)
  87 {
  88         struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  89
  90         if (input)
  91                 return readb(&port->lsr) & UART_LSR_DR;
  92         else
  93                 return !(readb(&port->lsr) & UART_LSR_THRE);
  94 }
  95
  96 static int uniphier_serial_probe(struct udevice *dev)
  97 {
  98         struct uniphier_serial_private_data *priv = dev_get_priv(dev);
  99         struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
 100
 101         priv->membase = map_sysmem(plat->base, sizeof(struct uniphier_serial));
 102
 103         if (!priv->membase)
 104                 return -ENOMEM;
 105
 106         return 0;
 107 }
 108
 109 static int uniphier_serial_remove(struct udevice *dev)
 110 {
 111         unmap_sysmem(uniphier_serial_port(dev));
 112
 113         return 0;
 114 }
 115
 116 #ifdef CONFIG_OF_CONTROL
 117 static const struct udevice_id uniphier_uart_of_match[] = {
 118         { .compatible = "panasonic,uniphier-uart" },
 119         {},
 120 };
 121
 122 static int uniphier_serial_ofdata_to_platdata(struct udevice *dev)
 123 {
 124         struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
 125         DECLARE_GLOBAL_DATA_PTR;
 126
 127         plat->base = fdtdec_get_addr(gd->fdt_blob, dev->of_offset, "reg");
 128         plat->uartclk = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
 129                                        "clock-frequency", 0);
 130
 131         return 0;
 132 }
 133 #endif
 134
 135 static const struct dm_serial_ops uniphier_serial_ops = {
 136         .setbrg = uniphier_serial_setbrg,
 137         .getc = uniphier_serial_getc,
 138         .putc = uniphier_serial_putc,
 139         .pending = uniphier_serial_pending,
 140 };
 141
 142 U_BOOT_DRIVER(uniphier_serial) = {
 143         .name = DRIVER_NAME,
 144         .id = UCLASS_SERIAL,
 145         .of_match = of_match_ptr(uniphier_uart_of_match),
 146         .ofdata_to_platdata = of_match_ptr(uniphier_serial_ofdata_to_platdata),
 147         .probe = uniphier_serial_probe,
 148         .remove = uniphier_serial_remove,
 149         .priv_auto_alloc_size = sizeof(struct uniphier_serial_private_data),
 150         .platdata_auto_alloc_size =
 151                                 sizeof(struct uniphier_serial_platform_data),
 152         .ops = &uniphier_serial_ops,
 153         .flags = DM_FLAG_PRE_RELOC,
 154 };