LXR uboot/drivers/serial/serial

   1/*
   2 * Copyright (C) 2012-2015 Masahiro Yamada <yamada.masahiro@socionext.com>
   3 *
   4 * SPDX-License-Identifier:     GPL-2.0+
   5 */
   6
   7#include <linux/io.h>
   8#include <linux/serial_reg.h>
   9#include <asm/errno.h>
  10#include <dm/device.h>
  11#include <mapmem.h>
  12#include <serial.h>
  13#include <fdtdec.h>
  14
  15/*
  16 * Note: Register map is slightly different from that of 16550.
  17 */
  18struct uniphier_serial {
  19        u32 rx;                 /* In:  Receive buffer */
  20#define tx rx                   /* Out: Transmit buffer */
  21        u32 ier;                /* Interrupt Enable Register */
  22        u32 iir;                /* In: Interrupt ID Register */
  23        u32 char_fcr;           /* Charactor / FIFO Control Register */
  24        u32 lcr_mcr;            /* Line/Modem Control Register */
  25#define LCR_SHIFT       8
  26#define LCR_MASK        (0xff << (LCR_SHIFT))
  27        u32 lsr;                /* In: Line Status Register */
  28        u32 msr;                /* In: Modem Status Register */
  29        u32 __rsv0;
  30        u32 __rsv1;
  31        u32 dlr;                /* Divisor Latch Register */
  32};
  33
  34struct uniphier_serial_private_data {
  35        struct uniphier_serial __iomem *membase;
  36        unsigned int uartclk;
  37};
  38
  39#define uniphier_serial_port(dev)       \
  40        ((struct uniphier_serial_private_data *)dev_get_priv(dev))->membase
  41
  42static int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
  43{
  44        struct uniphier_serial_private_data *priv = dev_get_priv(dev);
  45        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  46        const unsigned int mode_x_div = 16;
  47        unsigned int divisor;
  48
  49        divisor = DIV_ROUND_CLOSEST(priv->uartclk, mode_x_div * baudrate);
  50
  51        writel(divisor, &port->dlr);
  52
  53        return 0;
  54}
  55
  56static int uniphier_serial_getc(struct udevice *dev)
  57{
  58        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  59
  60        if (!(readl(&port->lsr) & UART_LSR_DR))
  61                return -EAGAIN;
  62
  63        return readl(&port->rx);
  64}
  65
  66static int uniphier_serial_putc(struct udevice *dev, const char c)
  67{
  68        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  69
  70        if (!(readl(&port->lsr) & UART_LSR_THRE))
  71                return -EAGAIN;
  72
  73        writel(c, &port->tx);
  74
  75        return 0;
  76}
  77
  78static int uniphier_serial_pending(struct udevice *dev, bool input)
  79{
  80        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  81
  82        if (input)
  83                return readl(&port->lsr) & UART_LSR_DR;
  84        else
  85                return !(readl(&port->lsr) & UART_LSR_THRE);
  86}
  87
  88static int uniphier_serial_probe(struct udevice *dev)
  89{
  90        DECLARE_GLOBAL_DATA_PTR;
  91        struct uniphier_serial_private_data *priv = dev_get_priv(dev);
  92        struct uniphier_serial __iomem *port;
  93        fdt_addr_t base;
  94        fdt_size_t size;
  95        u32 tmp;
  96
  97        base = fdtdec_get_addr_size(gd->fdt_blob, dev->of_offset, "reg", &size);
  98
  99        port = map_sysmem(base, size);
 100        if (!port)
 101                return -ENOMEM;
 102
 103        priv->membase = port;
 104
 105        priv->uartclk = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
 106                                       "clock-frequency", 0);
 107
 108        tmp = readl(&port->lcr_mcr);
 109        tmp &= ~LCR_MASK;
 110        tmp |= UART_LCR_WLEN8 << LCR_SHIFT;
 111        writel(tmp, &port->lcr_mcr);
 112
 113        return 0;
 114}
 115
 116static int uniphier_serial_remove(struct udevice *dev)
 117{
 118        unmap_sysmem(uniphier_serial_port(dev));
 119
 120        return 0;
 121}
 122
 123static const struct udevice_id uniphier_uart_of_match[] = {
 124        { .compatible = "socionext,uniphier-uart" },
 125        { /* sentinel */ }
 126};
 127
 128static const struct dm_serial_ops uniphier_serial_ops = {
 129        .setbrg = uniphier_serial_setbrg,
 130        .getc = uniphier_serial_getc,
 131        .putc = uniphier_serial_putc,
 132        .pending = uniphier_serial_pending,
 133};
 134
 135U_BOOT_DRIVER(uniphier_serial) = {
 136        .name = "uniphier-uart",
 137        .id = UCLASS_SERIAL,
 138        .of_match = uniphier_uart_of_match,
 139        .probe = uniphier_serial_probe,
 140        .remove = uniphier_serial_remove,
 141        .priv_auto_alloc_size = sizeof(struct uniphier_serial_private_data),
 142        .ops = &uniphier_serial_ops,
 143};
 144