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