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 <common.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 /*
  41  * These are the definitions for the Line Control Register
  42  */
  43 #define UART_LCR_WLS_8  0x03            /* 8 bit character length */
  44
  45 /*
  46  * These are the definitions for the Line Status Register
  47  */
  48 #define UART_LSR_DR     0x01            /* Data ready */
  49 #define UART_LSR_THRE   0x20            /* Xmit holding register empty */
  50
  51 struct uniphier_serial_private_data {
  52         struct uniphier_serial __iomem *membase;
  53 };
  54
  55 #define uniphier_serial_port(dev)       \
  56         ((struct uniphier_serial_private_data *)dev_get_priv(dev))->membase
  57
  58 static int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
  59 {
  60         struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
  61         struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  62         const unsigned int mode_x_div = 16;
  63         unsigned int divisor;
  64
  65         writeb(UART_LCR_WLS_8, &port->lcr);
  66
  67         divisor = DIV_ROUND_CLOSEST(plat->uartclk, mode_x_div * baudrate);
  68
  69         writew(divisor, &port->dlr);
  70
  71         return 0;
  72 }
  73
  74 static int uniphier_serial_getc(struct udevice *dev)
  75 {
  76         struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  77
  78         if (!(readb(&port->lsr) & UART_LSR_DR))
  79                 return -EAGAIN;
  80
  81         return readb(&port->rbr);
  82 }
  83
  84 static int uniphier_serial_putc(struct udevice *dev, const char c)
  85 {
  86         struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  87
  88         if (!(readb(&port->lsr) & UART_LSR_THRE))
  89                 return -EAGAIN;
  90
  91         writeb(c, &port->thr);
  92
  93         return 0;
  94 }
  95
  96 static int uniphier_serial_pending(struct udevice *dev, bool input)
  97 {
  98         struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  99
 100         if (input)
 101                 return readb(&port->lsr) & UART_LSR_DR;
 102         else
 103                 return !(readb(&port->lsr) & UART_LSR_THRE);
 104 }
 105
 106 static int uniphier_serial_probe(struct udevice *dev)
 107 {
 108         struct uniphier_serial_private_data *priv = dev_get_priv(dev);
 109         struct uniphier_serial_platform_data *plat = dev_get_platdata(dev);
 110
 111         priv->membase = map_sysmem(plat->base, sizeof(struct uniphier_serial));
 112
 113         if (!priv->membase)
 114                 return -ENOMEM;
 115
 116         return 0;
 117 }
 118
 119 static int uniphier_serial_remove(struct udevice *dev)
 120 {
 121         unmap_sysmem(uniphier_serial_port(dev));
 122
 123         return 0;
 124 }
 125
 126 #ifdef CONFIG_OF_CONTROL
 127 static const struct udevice_id uniphier_uart_of_match = {
 128         { .compatible = "panasonic,uniphier-uart"},
 129         {},
 130 };
 131
 132 static int uniphier_serial_ofdata_to_platdata(struct udevice *dev)
 133 {
 134         /*
 135          * TODO: Masahiro Yamada (yamada.m@jp.panasonic.com)
 136          *
 137          * Implement conversion code from DTB to platform data
 138          * when supporting CONFIG_OF_CONTROL on UniPhir platform.
 139          */
 140 }
 141 #endif
 142
 143 static const struct dm_serial_ops uniphier_serial_ops = {
 144         .setbrg = uniphier_serial_setbrg,
 145         .getc = uniphier_serial_getc,
 146         .putc = uniphier_serial_putc,
 147         .pending = uniphier_serial_pending,
 148 };
 149
 150 U_BOOT_DRIVER(uniphier_serial) = {
 151         .name = DRIVER_NAME,
 152         .id = UCLASS_SERIAL,
 153         .of_match = of_match_ptr(uniphier_uart_of_match),
 154         .ofdata_to_platdata = of_match_ptr(uniphier_serial_ofdata_to_platdata),
 155         .probe = uniphier_serial_probe,
 156         .remove = uniphier_serial_remove,
 157         .priv_auto_alloc_size = sizeof(struct uniphier_serial_private_data),
 158         .platdata_auto_alloc_size =
 159                                 sizeof(struct uniphier_serial_platform_data),
 160         .ops = &uniphier_serial_ops,
 161         .flags = DM_FLAG_PRE_RELOC,
 162 };