LXR uboot/drivers/serial/serial_bcm283x

   1/*
   2 * (C) Copyright 2016 Stephen Warren <swarren@wwwdotorg.org>
   3 *
   4 * Derived from pl01x code:
   5 *
   6 * (C) Copyright 2000
   7 * Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
   8 *
   9 * (C) Copyright 2004
  10 * ARM Ltd.
  11 * Philippe Robin, <philippe.robin@arm.com>
  12 *
  13 * SPDX-License-Identifier:     GPL-2.0+
  14 */
  15
  16/* Simple U-Boot driver for the BCM283x mini UART */
  17
  18#include <common.h>
  19#include <dm.h>
  20#include <errno.h>
  21#include <watchdog.h>
  22#include <asm/io.h>
  23#include <serial.h>
  24#include <dm/platform_data/serial_bcm283x_mu.h>
  25#include <linux/compiler.h>
  26#include <fdtdec.h>
  27
  28DECLARE_GLOBAL_DATA_PTR;
  29
  30struct bcm283x_mu_regs {
  31        u32 io;
  32        u32 iir;
  33        u32 ier;
  34        u32 lcr;
  35        u32 mcr;
  36        u32 lsr;
  37        u32 msr;
  38        u32 scratch;
  39        u32 cntl;
  40        u32 stat;
  41        u32 baud;
  42};
  43
  44#define BCM283X_MU_LCR_DATA_SIZE_8      3
  45
  46#define BCM283X_MU_LSR_TX_IDLE          BIT(6)
  47/* This actually means not full, but is named not empty in the docs */
  48#define BCM283X_MU_LSR_TX_EMPTY         BIT(5)
  49#define BCM283X_MU_LSR_RX_READY         BIT(0)
  50
  51struct bcm283x_mu_priv {
  52        struct bcm283x_mu_regs *regs;
  53};
  54
  55static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate)
  56{
  57        struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
  58        struct bcm283x_mu_priv *priv = dev_get_priv(dev);
  59        struct bcm283x_mu_regs *regs = priv->regs;
  60        u32 divider;
  61
  62        if (plat->disabled || plat->skip_init)
  63                return 0;
  64
  65        divider = plat->clock / (baudrate * 8);
  66
  67        writel(BCM283X_MU_LCR_DATA_SIZE_8, &regs->lcr);
  68        writel(divider - 1, &regs->baud);
  69
  70        return 0;
  71}
  72
  73static int bcm283x_mu_serial_probe(struct udevice *dev)
  74{
  75        struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
  76        struct bcm283x_mu_priv *priv = dev_get_priv(dev);
  77
  78        if (plat->disabled)
  79                return -ENODEV;
  80
  81        priv->regs = (struct bcm283x_mu_regs *)plat->base;
  82
  83        return 0;
  84}
  85
  86static int bcm283x_mu_serial_getc(struct udevice *dev)
  87{
  88        struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
  89        struct bcm283x_mu_priv *priv = dev_get_priv(dev);
  90        struct bcm283x_mu_regs *regs = priv->regs;
  91        u32 data;
  92
  93        if (plat->disabled)
  94                return -EAGAIN;
  95
  96        /* Wait until there is data in the FIFO */
  97        if (!(readl(&regs->lsr) & BCM283X_MU_LSR_RX_READY))
  98                return -EAGAIN;
  99
 100        data = readl(&regs->io);
 101
 102        return (int)data;
 103}
 104
 105static int bcm283x_mu_serial_putc(struct udevice *dev, const char data)
 106{
 107        struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
 108        struct bcm283x_mu_priv *priv = dev_get_priv(dev);
 109        struct bcm283x_mu_regs *regs = priv->regs;
 110
 111        if (plat->disabled)
 112                return 0;
 113
 114        /* Wait until there is space in the FIFO */
 115        if (!(readl(&regs->lsr) & BCM283X_MU_LSR_TX_EMPTY))
 116                return -EAGAIN;
 117
 118        /* Send the character */
 119        writel(data, &regs->io);
 120
 121        return 0;
 122}
 123
 124static int bcm283x_mu_serial_pending(struct udevice *dev, bool input)
 125{
 126        struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
 127        struct bcm283x_mu_priv *priv = dev_get_priv(dev);
 128        struct bcm283x_mu_regs *regs = priv->regs;
 129        unsigned int lsr;
 130
 131        if (plat->disabled)
 132                return 0;
 133
 134        lsr = readl(&regs->lsr);
 135
 136        if (input) {
 137                WATCHDOG_RESET();
 138                return (lsr & BCM283X_MU_LSR_RX_READY) ? 1 : 0;
 139        } else {
 140                return (lsr & BCM283X_MU_LSR_TX_IDLE) ? 0 : 1;
 141        }
 142}
 143
 144static const struct dm_serial_ops bcm283x_mu_serial_ops = {
 145        .putc = bcm283x_mu_serial_putc,
 146        .pending = bcm283x_mu_serial_pending,
 147        .getc = bcm283x_mu_serial_getc,
 148        .setbrg = bcm283x_mu_serial_setbrg,
 149};
 150
 151#if CONFIG_IS_ENABLED(OF_CONTROL)
 152static const struct udevice_id bcm283x_mu_serial_id[] = {
 153        {.compatible = "brcm,bcm2835-aux-uart"},
 154        {}
 155};
 156
 157static int bcm283x_mu_serial_ofdata_to_platdata(struct udevice *dev)
 158{
 159        struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
 160        fdt_addr_t addr;
 161
 162        addr = devfdt_get_addr(dev);
 163        if (addr == FDT_ADDR_T_NONE)
 164                return -EINVAL;
 165
 166        plat->base = addr;
 167        plat->clock = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev), "clock",
 168                                     1);
 169        plat->skip_init = fdtdec_get_bool(gd->fdt_blob, dev_of_offset(dev),
 170                                          "skip-init");
 171        plat->disabled = false;
 172        return 0;
 173}
 174#endif
 175
 176U_BOOT_DRIVER(serial_bcm283x_mu) = {
 177        .name = "serial_bcm283x_mu",
 178        .id = UCLASS_SERIAL,
 179        .of_match = of_match_ptr(bcm283x_mu_serial_id),
 180        .ofdata_to_platdata = of_match_ptr(bcm283x_mu_serial_ofdata_to_platdata),
 181        .platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata),
 182        .probe = bcm283x_mu_serial_probe,
 183        .ops = &bcm283x_mu_serial_ops,
 184        .flags = DM_FLAG_PRE_RELOC,
 185        .priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv),
 186};
 187