drivers/serial/serial_xuartlite.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * (C) Copyright 2008 - 2015 Michal Simek <monstr@monstr.eu>
   4  * Clean driver and add xilinx constant from header file
   5  *
   6  * (C) Copyright 2004 Atmark Techno, Inc.
   7  * Yasushi SHOJI <yashi@atmark-techno.com>
   8  */
   9
  10 #include <config.h>
  11 #include <common.h>
  12 #include <dm.h>
  13 #include <asm/io.h>
  14 #include <linux/bitops.h>
  15 #include <linux/compiler.h>
  16 #include <serial.h>
  17
  18 #define SR_TX_FIFO_FULL         BIT(3) /* transmit FIFO full */
  19 #define SR_TX_FIFO_EMPTY        BIT(2) /* transmit FIFO empty */
  20 #define SR_RX_FIFO_VALID_DATA   BIT(0) /* data in receive FIFO */
  21 #define SR_RX_FIFO_FULL         BIT(1) /* receive FIFO full */
  22
  23 #define ULITE_CONTROL_RST_TX    0x01
  24 #define ULITE_CONTROL_RST_RX    0x02
  25
  26 static bool little_endian;
  27
  28 struct uartlite {
  29         unsigned int rx_fifo;
  30         unsigned int tx_fifo;
  31         unsigned int status;
  32         unsigned int control;
  33 };
  34
  35 struct uartlite_plat {
  36         struct uartlite *regs;
  37 };
  38
  39 static u32 uart_in32(void __iomem *addr)
  40 {
  41         if (little_endian)
  42                 return in_le32(addr);
  43         else
  44                 return in_be32(addr);
  45 }
  46
  47 static void uart_out32(void __iomem *addr, u32 val)
  48 {
  49         if (little_endian)
  50                 out_le32(addr, val);
  51         else
  52                 out_be32(addr, val);
  53 }
  54
  55 static int uartlite_serial_putc(struct udevice *dev, const char ch)
  56 {
  57         struct uartlite_plat *plat = dev_get_plat(dev);
  58         struct uartlite *regs = plat->regs;
  59
  60         if (uart_in32(&regs->status) & SR_TX_FIFO_FULL)
  61                 return -EAGAIN;
  62
  63         uart_out32(&regs->tx_fifo, ch & 0xff);
  64
  65         return 0;
  66 }
  67
  68 static int uartlite_serial_getc(struct udevice *dev)
  69 {
  70         struct uartlite_plat *plat = dev_get_plat(dev);
  71         struct uartlite *regs = plat->regs;
  72
  73         if (!(uart_in32(&regs->status) & SR_RX_FIFO_VALID_DATA))
  74                 return -EAGAIN;
  75
  76         return uart_in32(&regs->rx_fifo) & 0xff;
  77 }
  78
  79 static int uartlite_serial_pending(struct udevice *dev, bool input)
  80 {
  81         struct uartlite_plat *plat = dev_get_plat(dev);
  82         struct uartlite *regs = plat->regs;
  83
  84         if (input)
  85                 return uart_in32(&regs->status) & SR_RX_FIFO_VALID_DATA;
  86
  87         return !(uart_in32(&regs->status) & SR_TX_FIFO_EMPTY);
  88 }
  89
  90 static int uartlite_serial_probe(struct udevice *dev)
  91 {
  92         struct uartlite_plat *plat = dev_get_plat(dev);
  93         struct uartlite *regs = plat->regs;
  94         int ret;
  95
  96         uart_out32(&regs->control, 0);
  97         uart_out32(&regs->control, ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX);
  98         ret = uart_in32(&regs->status);
  99         /* Endianness detection */
 100         if ((ret & SR_TX_FIFO_EMPTY) != SR_TX_FIFO_EMPTY) {
 101                 little_endian = true;
 102                 uart_out32(&regs->control, ULITE_CONTROL_RST_RX |
 103                            ULITE_CONTROL_RST_TX);
 104         }
 105
 106         return 0;
 107 }
 108
 109 static int uartlite_serial_of_to_plat(struct udevice *dev)
 110 {
 111         struct uartlite_plat *plat = dev_get_plat(dev);
 112
 113         plat->regs = dev_read_addr_ptr(dev);
 114
 115         return 0;
 116 }
 117
 118 static const struct dm_serial_ops uartlite_serial_ops = {
 119         .putc = uartlite_serial_putc,
 120         .pending = uartlite_serial_pending,
 121         .getc = uartlite_serial_getc,
 122 };
 123
 124 static const struct udevice_id uartlite_serial_ids[] = {
 125         { .compatible = "xlnx,opb-uartlite-1.00.b", },
 126         { .compatible = "xlnx,xps-uartlite-1.00.a" },
 127         { }
 128 };
 129
 130 U_BOOT_DRIVER(serial_uartlite) = {
 131         .name   = "serial_uartlite",
 132         .id     = UCLASS_SERIAL,
 133         .of_match = uartlite_serial_ids,
 134         .of_to_plat = uartlite_serial_of_to_plat,
 135         .plat_auto      = sizeof(struct uartlite_plat),
 136         .probe = uartlite_serial_probe,
 137         .ops    = &uartlite_serial_ops,
 138 };
 139
 140 #ifdef CONFIG_DEBUG_UART_UARTLITE
 141
 142 #include <debug_uart.h>
 143
 144 static inline void _debug_uart_init(void)
 145 {
 146         struct uartlite *regs = (struct uartlite *)CONFIG_DEBUG_UART_BASE;
 147         int ret;
 148
 149         uart_out32(&regs->control, 0);
 150         uart_out32(&regs->control, ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX);
 151         ret = uart_in32(&regs->status);
 152         /* Endianness detection */
 153         if ((ret & SR_TX_FIFO_EMPTY) != SR_TX_FIFO_EMPTY) {
 154                 little_endian = true;
 155                 uart_out32(&regs->control, ULITE_CONTROL_RST_RX |
 156                            ULITE_CONTROL_RST_TX);
 157         }
 158 }
 159
 160 static inline void _debug_uart_putc(int ch)
 161 {
 162         struct uartlite *regs = (struct uartlite *)CONFIG_DEBUG_UART_BASE;
 163
 164         while (uart_in32(&regs->status) & SR_TX_FIFO_FULL)
 165                 ;
 166
 167         uart_out32(&regs->tx_fifo, ch & 0xff);
 168 }
 169
 170 DEBUG_UART_FUNCS
 171 #endif