drivers/serial/altera_jtag_uart.c

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