drivers/serial/altera_jtag_uart.c

   1 /*
   2  * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
   3  * Scott McNutt <smcnutt@psyent.com>
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <dm.h>
  10 #include <errno.h>
  11 #include <asm/io.h>
  12 #include <linux/compiler.h>
  13 #include <serial.h>
  14
  15 struct altera_jtaguart_regs {
  16         u32     data;                   /* Data register */
  17         u32     control;                /* Control register */
  18 };
  19
  20 struct altera_jtaguart_platdata {
  21         struct altera_jtaguart_regs *regs;
  22 };
  23
  24 /* data register */
  25 #define ALTERA_JTAG_RVALID      (1<<15)         /* Read valid */
  26
  27 /* control register */
  28 #define ALTERA_JTAG_AC          (1 << 10)       /* activity indicator */
  29 #define ALTERA_JTAG_RRDY        (1 << 12)       /* read available */
  30 #define ALTERA_JTAG_WSPACE(d)   ((d)>>16)       /* Write space avail */
  31 /* Write fifo size. FIXME: this should be extracted with sopc2dts */
  32 #define ALTERA_JTAG_WRITE_DEPTH 64
  33
  34 DECLARE_GLOBAL_DATA_PTR;
  35
  36 static int altera_jtaguart_setbrg(struct udevice *dev, int baudrate)
  37 {
  38         return 0;
  39 }
  40
  41 static int altera_jtaguart_putc(struct udevice *dev, const char ch)
  42 {
  43         struct altera_jtaguart_platdata *plat = dev->platdata;
  44         struct altera_jtaguart_regs *const regs = plat->regs;
  45         u32 st = readl(&regs->control);
  46
  47 #ifdef CONFIG_ALTERA_JTAG_UART_BYPASS
  48         if (!(st & ALTERA_JTAG_AC)) /* no connection yet */
  49                 return -ENETUNREACH;
  50 #endif
  51
  52         if (ALTERA_JTAG_WSPACE(st) == 0)
  53                 return -EAGAIN;
  54
  55         writel(ch, &regs->data);
  56
  57         return 0;
  58 }
  59
  60 static int altera_jtaguart_pending(struct udevice *dev, bool input)
  61 {
  62         struct altera_jtaguart_platdata *plat = dev->platdata;
  63         struct altera_jtaguart_regs *const regs = plat->regs;
  64         u32 st = readl(&regs->control);
  65
  66         if (input)
  67                 return st & ALTERA_JTAG_RRDY ? 1 : 0;
  68         else
  69                 return !(ALTERA_JTAG_WSPACE(st) == ALTERA_JTAG_WRITE_DEPTH);
  70 }
  71
  72 static int altera_jtaguart_getc(struct udevice *dev)
  73 {
  74         struct altera_jtaguart_platdata *plat = dev->platdata;
  75         struct altera_jtaguart_regs *const regs = plat->regs;
  76         u32 val;
  77
  78         val = readl(&regs->data);
  79
  80         if (!(val & ALTERA_JTAG_RVALID))
  81                 return -EAGAIN;
  82
  83         return val & 0xff;
  84 }
  85
  86 static int altera_jtaguart_probe(struct udevice *dev)
  87 {
  88 #ifdef CONFIG_ALTERA_JTAG_UART_BYPASS
  89         struct altera_jtaguart_platdata *plat = dev->platdata;
  90         struct altera_jtaguart_regs *const regs = plat->regs;
  91
  92         writel(ALTERA_JTAG_AC, &regs->control); /* clear AC flag */
  93 #endif
  94         return 0;
  95 }
  96
  97 static int altera_jtaguart_ofdata_to_platdata(struct udevice *dev)
  98 {
  99         struct altera_jtaguart_platdata *plat = dev_get_platdata(dev);
 100
 101         plat->regs = ioremap(dev_get_addr(dev),
 102                 sizeof(struct altera_jtaguart_regs));
 103
 104         return 0;
 105 }
 106
 107 static const struct dm_serial_ops altera_jtaguart_ops = {
 108         .putc = altera_jtaguart_putc,
 109         .pending = altera_jtaguart_pending,
 110         .getc = altera_jtaguart_getc,
 111         .setbrg = altera_jtaguart_setbrg,
 112 };
 113
 114 static const struct udevice_id altera_jtaguart_ids[] = {
 115         { .compatible = "altr,juart-1.0", },
 116         { }
 117 };
 118
 119 U_BOOT_DRIVER(altera_jtaguart) = {
 120         .name   = "altera_jtaguart",
 121         .id     = UCLASS_SERIAL,
 122         .of_match = altera_jtaguart_ids,
 123         .ofdata_to_platdata = altera_jtaguart_ofdata_to_platdata,
 124         .platdata_auto_alloc_size = sizeof(struct altera_jtaguart_platdata),
 125         .probe = altera_jtaguart_probe,
 126         .ops    = &altera_jtaguart_ops,
 127         .flags = DM_FLAG_PRE_RELOC,
 128 };
 129
 130 #ifdef CONFIG_DEBUG_UART_ALTERA_JTAGUART
 131
 132 #include <debug_uart.h>
 133
 134 void debug_uart_init(void)
 135 {
 136 }
 137
 138 static inline void _debug_uart_putc(int ch)
 139 {
 140         struct altera_jtaguart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
 141
 142         while (1) {
 143                 u32 st = readl(&regs->control);
 144
 145                 if (ALTERA_JTAG_WSPACE(st))
 146                         break;
 147         }
 148
 149         writel(ch, &regs->data);
 150 }
 151
 152 DEBUG_UART_FUNCS
 153
 154 #endif