arch/mips/cavium-octeon/serial.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2004-2007 Cavium Networks
   7  */
   8 #include <linux/console.h>
   9 #include <linux/module.h>
  10 #include <linux/init.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/serial.h>
  13 #include <linux/serial_8250.h>
  14 #include <linux/serial_reg.h>
  15 #include <linux/tty.h>
  16 #include <linux/irq.h>
  17
  18 #include <asm/time.h>
  19
  20 #include <asm/octeon/octeon.h>
  21
  22 #define DEBUG_UART 1
  23
  24 unsigned int octeon_serial_in(struct uart_port *up, int offset)
  25 {
  26         int rv = cvmx_read_csr((uint64_t)(up->membase + (offset << 3)));
  27         if (offset == UART_IIR && (rv & 0xf) == 7) {
  28                 /* Busy interrupt, read the USR (39) and try again. */
  29                 cvmx_read_csr((uint64_t)(up->membase + (39 << 3)));
  30                 rv = cvmx_read_csr((uint64_t)(up->membase + (offset << 3)));
  31         }
  32         return rv;
  33 }
  34
  35 void octeon_serial_out(struct uart_port *up, int offset, int value)
  36 {
  37         /*
  38          * If bits 6 or 7 of the OCTEON UART's LCR are set, it quits
  39          * working.
  40          */
  41         if (offset == UART_LCR)
  42                 value &= 0x9f;
  43         cvmx_write_csr((uint64_t)(up->membase + (offset << 3)), (u8)value);
  44 }
  45
  46 static int octeon_serial_probe(struct platform_device *pdev)
  47 {
  48         int irq, res;
  49         struct resource *res_mem;
  50         struct uart_8250_port up;
  51
  52         /* All adaptors have an irq.  */
  53         irq = platform_get_irq(pdev, 0);
  54         if (irq < 0)
  55                 return irq;
  56
  57         memset(&up, 0, sizeof(up));
  58
  59         up.port.flags = ASYNC_SKIP_TEST | UPF_SHARE_IRQ | UPF_FIXED_TYPE;
  60         up.port.type = PORT_OCTEON;
  61         up.port.iotype = UPIO_MEM;
  62         up.port.regshift = 3;
  63         up.port.dev = &pdev->dev;
  64
  65         if (octeon_is_simulation())
  66                 /* Make simulator output fast*/
  67                 up.port.uartclk = 115200 * 16;
  68         else
  69                 up.port.uartclk = octeon_get_io_clock_rate();
  70
  71         up.port.serial_in = octeon_serial_in;
  72         up.port.serial_out = octeon_serial_out;
  73         up.port.irq = irq;
  74
  75         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  76         if (res_mem == NULL) {
  77                 dev_err(&pdev->dev, "found no memory resource\n");
  78                 return -ENXIO;
  79         }
  80         up.port.mapbase = res_mem->start;
  81         up.port.membase = ioremap(res_mem->start, resource_size(res_mem));
  82
  83         res = serial8250_register_8250_port(&up);
  84
  85         return res >= 0 ? 0 : res;
  86 }
  87
  88 static struct of_device_id octeon_serial_match[] = {
  89         {
  90                 .compatible = "cavium,octeon-3860-uart",
  91         },
  92         {},
  93 };
  94 MODULE_DEVICE_TABLE(of, octeon_serial_match);
  95
  96 static struct platform_driver octeon_serial_driver = {
  97         .probe          = octeon_serial_probe,
  98         .driver         = {
  99                 .owner  = THIS_MODULE,
 100                 .name   = "octeon_serial",
 101                 .of_match_table = octeon_serial_match,
 102         },
 103 };
 104
 105 static int __init octeon_serial_init(void)
 106 {
 107         return platform_driver_register(&octeon_serial_driver);
 108 }
 109 late_initcall(octeon_serial_init);