LXR uboot/drivers/serial/serial

   1/*
   2 * Copyright (C) 2012-2015 Panasonic Corporation
   3 * Copyright (C) 2015-2016 Socionext Inc.
   4 *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
   5 *
   6 * SPDX-License-Identifier:     GPL-2.0+
   7 */
   8
   9#include <linux/io.h>
  10#include <linux/serial_reg.h>
  11#include <linux/sizes.h>
  12#include <linux/errno.h>
  13#include <dm/device.h>
  14#include <serial.h>
  15#include <fdtdec.h>
  16
  17/*
  18 * Note: Register map is slightly different from that of 16550.
  19 */
  20struct uniphier_serial {
  21        u32 rx;                 /* In:  Receive buffer */
  22#define tx rx                   /* Out: Transmit buffer */
  23        u32 ier;                /* Interrupt Enable Register */
  24        u32 iir;                /* In: Interrupt ID Register */
  25        u32 char_fcr;           /* Charactor / FIFO Control Register */
  26        u32 lcr_mcr;            /* Line/Modem Control Register */
  27#define LCR_SHIFT       8
  28#define LCR_MASK        (0xff << (LCR_SHIFT))
  29        u32 lsr;                /* In: Line Status Register */
  30        u32 msr;                /* In: Modem Status Register */
  31        u32 __rsv0;
  32        u32 __rsv1;
  33        u32 dlr;                /* Divisor Latch Register */
  34};
  35
  36struct uniphier_serial_private_data {
  37        struct uniphier_serial __iomem *membase;
  38        unsigned int uartclk;
  39};
  40
  41#define uniphier_serial_port(dev)       \
  42        ((struct uniphier_serial_private_data *)dev_get_priv(dev))->membase
  43
  44static int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
  45{
  46        struct uniphier_serial_private_data *priv = dev_get_priv(dev);
  47        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  48        const unsigned int mode_x_div = 16;
  49        unsigned int divisor;
  50
  51        divisor = DIV_ROUND_CLOSEST(priv->uartclk, mode_x_div * baudrate);
  52
  53        writel(divisor, &port->dlr);
  54
  55        return 0;
  56}
  57
  58static int uniphier_serial_getc(struct udevice *dev)
  59{
  60        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  61
  62        if (!(readl(&port->lsr) & UART_LSR_DR))
  63                return -EAGAIN;
  64
  65        return readl(&port->rx);
  66}
  67
  68static int uniphier_serial_putc(struct udevice *dev, const char c)
  69{
  70        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  71
  72        if (!(readl(&port->lsr) & UART_LSR_THRE))
  73                return -EAGAIN;
  74
  75        writel(c, &port->tx);
  76
  77        return 0;
  78}
  79
  80static int uniphier_serial_pending(struct udevice *dev, bool input)
  81{
  82        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  83
  84        if (input)
  85                return readl(&port->lsr) & UART_LSR_DR;
  86        else
  87                return !(readl(&port->lsr) & UART_LSR_THRE);
  88}
  89
  90static int uniphier_serial_probe(struct udevice *dev)
  91{
  92        DECLARE_GLOBAL_DATA_PTR;
  93        struct uniphier_serial_private_data *priv = dev_get_priv(dev);
  94        struct uniphier_serial __iomem *port;
  95        fdt_addr_t base;
  96        u32 tmp;
  97
  98        base = dev_get_addr(dev);
  99        if (base == FDT_ADDR_T_NONE)
 100                return -EINVAL;
 101
 102        port = devm_ioremap(dev, base, SZ_64);
 103        if (!port)
 104                return -ENOMEM;
 105
 106        priv->membase = port;
 107
 108        priv->uartclk = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
 109                                       "clock-frequency", 0);
 110
 111        tmp = readl(&port->lcr_mcr);
 112        tmp &= ~LCR_MASK;
 113        tmp |= UART_LCR_WLEN8 << LCR_SHIFT;
 114        writel(tmp, &port->lcr_mcr);
 115
 116        return 0;
 117}
 118
 119static const struct udevice_id uniphier_uart_of_match[] = {
 120        { .compatible = "socionext,uniphier-uart" },
 121        { /* sentinel */ }
 122};
 123
 124static const struct dm_serial_ops uniphier_serial_ops = {
 125        .setbrg = uniphier_serial_setbrg,
 126        .getc = uniphier_serial_getc,
 127        .putc = uniphier_serial_putc,
 128        .pending = uniphier_serial_pending,
 129};
 130
 131U_BOOT_DRIVER(uniphier_serial) = {
 132        .name = "uniphier-uart",
 133        .id = UCLASS_SERIAL,
 134        .of_match = uniphier_uart_of_match,
 135        .probe = uniphier_serial_probe,
 136        .priv_auto_alloc_size = sizeof(struct uniphier_serial_private_data),
 137        .ops = &uniphier_serial_ops,
 138};
 139