LXR uboot/drivers/serial/altera

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
   4 * Scott McNutt <smcnutt@psyent.com>
   5 */
   6
   7#include <common.h>
   8#include <dm.h>
   9#include <errno.h>
  10#include <serial.h>
  11#include <asm/io.h>
  12#include <linux/bitops.h>
  13
  14/* status register */
  15#define ALTERA_UART_TMT         BIT(5)  /* tx empty */
  16#define ALTERA_UART_TRDY        BIT(6)  /* tx ready */
  17#define ALTERA_UART_RRDY        BIT(7)  /* rx ready */
  18
  19struct altera_uart_regs {
  20        u32     rxdata;         /* Rx data reg */
  21        u32     txdata;         /* Tx data reg */
  22        u32     status;         /* Status reg */
  23        u32     control;        /* Control reg */
  24        u32     divisor;        /* Baud rate divisor reg */
  25        u32     endofpacket;    /* End-of-packet reg */
  26};
  27
  28struct altera_uart_platdata {
  29        struct altera_uart_regs *regs;
  30        unsigned int uartclk;
  31};
  32
  33static int altera_uart_setbrg(struct udevice *dev, int baudrate)
  34{
  35        struct altera_uart_platdata *plat = dev->platdata;
  36        struct altera_uart_regs *const regs = plat->regs;
  37        u32 div;
  38
  39        div = (plat->uartclk / baudrate) - 1;
  40        writel(div, &regs->divisor);
  41
  42        return 0;
  43}
  44
  45static int altera_uart_putc(struct udevice *dev, const char ch)
  46{
  47        struct altera_uart_platdata *plat = dev->platdata;
  48        struct altera_uart_regs *const regs = plat->regs;
  49
  50        if (!(readl(&regs->status) & ALTERA_UART_TRDY))
  51                return -EAGAIN;
  52
  53        writel(ch, &regs->txdata);
  54
  55        return 0;
  56}
  57
  58static int altera_uart_pending(struct udevice *dev, bool input)
  59{
  60        struct altera_uart_platdata *plat = dev->platdata;
  61        struct altera_uart_regs *const regs = plat->regs;
  62        u32 st = readl(&regs->status);
  63
  64        if (input)
  65                return st & ALTERA_UART_RRDY ? 1 : 0;
  66        else
  67                return !(st & ALTERA_UART_TMT);
  68}
  69
  70static int altera_uart_getc(struct udevice *dev)
  71{
  72        struct altera_uart_platdata *plat = dev->platdata;
  73        struct altera_uart_regs *const regs = plat->regs;
  74
  75        if (!(readl(&regs->status) & ALTERA_UART_RRDY))
  76                return -EAGAIN;
  77
  78        return readl(&regs->rxdata) & 0xff;
  79}
  80
  81static int altera_uart_probe(struct udevice *dev)
  82{
  83        return 0;
  84}
  85
  86static int altera_uart_ofdata_to_platdata(struct udevice *dev)
  87{
  88        struct altera_uart_platdata *plat = dev_get_platdata(dev);
  89
  90        plat->regs = map_physmem(dev_read_addr(dev),
  91                                 sizeof(struct altera_uart_regs),
  92                                 MAP_NOCACHE);
  93        plat->uartclk = dev_read_u32_default(dev, "clock-frequency", 0);
  94
  95        return 0;
  96}
  97
  98static const struct dm_serial_ops altera_uart_ops = {
  99        .putc = altera_uart_putc,
 100        .pending = altera_uart_pending,
 101        .getc = altera_uart_getc,
 102        .setbrg = altera_uart_setbrg,
 103};
 104
 105static const struct udevice_id altera_uart_ids[] = {
 106        { .compatible = "altr,uart-1.0" },
 107        {}
 108};
 109
 110U_BOOT_DRIVER(altera_uart) = {
 111        .name   = "altera_uart",
 112        .id     = UCLASS_SERIAL,
 113        .of_match = altera_uart_ids,
 114        .ofdata_to_platdata = altera_uart_ofdata_to_platdata,
 115        .platdata_auto_alloc_size = sizeof(struct altera_uart_platdata),
 116        .probe = altera_uart_probe,
 117        .ops    = &altera_uart_ops,
 118};
 119
 120#ifdef CONFIG_DEBUG_UART_ALTERA_UART
 121
 122#include <debug_uart.h>
 123
 124static inline void _debug_uart_init(void)
 125{
 126        struct altera_uart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
 127        u32 div;
 128
 129        div = (CONFIG_DEBUG_UART_CLOCK / CONFIG_BAUDRATE) - 1;
 130        writel(div, &regs->divisor);
 131}
 132
 133static inline void _debug_uart_putc(int ch)
 134{
 135        struct altera_uart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
 136
 137        while (1) {
 138                u32 st = readl(&regs->status);
 139
 140                if (st & ALTERA_UART_TRDY)
 141                        break;
 142        }
 143
 144        writel(ch, &regs->txdata);
 145}
 146
 147DEBUG_UART_FUNCS
 148
 149#endif
 150