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 <linux/sizes.h>
  10#include <asm/errno.h>
  11#include <dm/device.h>
  12#include <mapmem.h>
  13#include <serial.h>
  14#include <fdtdec.h>
  15
  16/*
  17 * Note: Register map is slightly different from that of 16550.
  18 */
  19struct uniphier_serial {
  20        u32 rx;                 /* In:  Receive buffer */
  21#define tx rx                   /* Out: Transmit buffer */
  22        u32 ier;                /* Interrupt Enable Register */
  23        u32 iir;                /* In: Interrupt ID Register */
  24        u32 char_fcr;           /* Charactor / FIFO Control Register */
  25        u32 lcr_mcr;            /* Line/Modem Control Register */
  26#define LCR_SHIFT       8
  27#define LCR_MASK        (0xff << (LCR_SHIFT))
  28        u32 lsr;                /* In: Line Status Register */
  29        u32 msr;                /* In: Modem Status Register */
  30        u32 __rsv0;
  31        u32 __rsv1;
  32        u32 dlr;                /* Divisor Latch Register */
  33};
  34
  35struct uniphier_serial_private_data {
  36        struct uniphier_serial __iomem *membase;
  37        unsigned int uartclk;
  38};
  39
  40#define uniphier_serial_port(dev)       \
  41        ((struct uniphier_serial_private_data *)dev_get_priv(dev))->membase
  42
  43static int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
  44{
  45        struct uniphier_serial_private_data *priv = dev_get_priv(dev);
  46        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  47        const unsigned int mode_x_div = 16;
  48        unsigned int divisor;
  49
  50        divisor = DIV_ROUND_CLOSEST(priv->uartclk, mode_x_div * baudrate);
  51
  52        writel(divisor, &port->dlr);
  53
  54        return 0;
  55}
  56
  57static int uniphier_serial_getc(struct udevice *dev)
  58{
  59        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  60
  61        if (!(readl(&port->lsr) & UART_LSR_DR))
  62                return -EAGAIN;
  63
  64        return readl(&port->rx);
  65}
  66
  67static int uniphier_serial_putc(struct udevice *dev, const char c)
  68{
  69        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  70
  71        if (!(readl(&port->lsr) & UART_LSR_THRE))
  72                return -EAGAIN;
  73
  74        writel(c, &port->tx);
  75
  76        return 0;
  77}
  78
  79static int uniphier_serial_pending(struct udevice *dev, bool input)
  80{
  81        struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
  82
  83        if (input)
  84                return readl(&port->lsr) & UART_LSR_DR;
  85        else
  86                return !(readl(&port->lsr) & UART_LSR_THRE);
  87}
  88
  89static int uniphier_serial_probe(struct udevice *dev)
  90{
  91        DECLARE_GLOBAL_DATA_PTR;
  92        struct uniphier_serial_private_data *priv = dev_get_priv(dev);
  93        struct uniphier_serial __iomem *port;
  94        fdt_addr_t base;
  95        u32 tmp;
  96
  97        base = dev_get_addr(dev);
  98        if (base == FDT_ADDR_T_NONE)
  99                return -EINVAL;
 100
 101        port = map_sysmem(base, SZ_64);
 102        if (!port)
 103                return -ENOMEM;
 104
 105        priv->membase = port;
 106
 107        priv->uartclk = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
 108                                       "clock-frequency", 0);
 109
 110        tmp = readl(&port->lcr_mcr);
 111        tmp &= ~LCR_MASK;
 112        tmp |= UART_LCR_WLEN8 << LCR_SHIFT;
 113        writel(tmp, &port->lcr_mcr);
 114
 115        return 0;
 116}
 117
 118static int uniphier_serial_remove(struct udevice *dev)
 119{
 120        unmap_sysmem(uniphier_serial_port(dev));
 121
 122        return 0;
 123}
 124
 125static const struct udevice_id uniphier_uart_of_match[] = {
 126        { .compatible = "socionext,uniphier-uart" },
 127        { /* sentinel */ }
 128};
 129
 130static const struct dm_serial_ops uniphier_serial_ops = {
 131        .setbrg = uniphier_serial_setbrg,
 132        .getc = uniphier_serial_getc,
 133        .putc = uniphier_serial_putc,
 134        .pending = uniphier_serial_pending,
 135};
 136
 137U_BOOT_DRIVER(uniphier_serial) = {
 138        .name = "uniphier-uart",
 139        .id = UCLASS_SERIAL,
 140        .of_match = uniphier_uart_of_match,
 141        .probe = uniphier_serial_probe,
 142        .remove = uniphier_serial_remove,
 143        .priv_auto_alloc_size = sizeof(struct uniphier_serial_private_data),
 144        .ops = &uniphier_serial_ops,
 145};
 146