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