Linux Kernel  3.7.1
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serial.c
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1 /*
2  * TI DaVinci serial driver
3  *
4  * Copyright (C) 2006 Texas Instruments.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19  *
20  */
21 
22 #include <linux/kernel.h>
23 #include <linux/init.h>
24 #include <linux/serial_8250.h>
25 #include <linux/serial_reg.h>
26 #include <linux/platform_device.h>
27 #include <linux/delay.h>
28 #include <linux/clk.h>
29 #include <linux/io.h>
30 
31 #include <mach/serial.h>
32 #include <mach/cputype.h>
33 
34 static inline unsigned int serial_read_reg(struct plat_serial8250_port *up,
35  int offset)
36 {
37  offset <<= up->regshift;
38 
39  WARN_ONCE(!up->membase, "unmapped read: uart[%d]\n", offset);
40 
41  return (unsigned int)__raw_readl(up->membase + offset);
42 }
43 
44 static inline void serial_write_reg(struct plat_serial8250_port *p, int offset,
45  int value)
46 {
47  offset <<= p->regshift;
48 
49  WARN_ONCE(!p->membase, "unmapped write: uart[%d]\n", offset);
50 
51  __raw_writel(value, p->membase + offset);
52 }
53 
54 static void __init davinci_serial_reset(struct plat_serial8250_port *p)
55 {
56  unsigned int pwremu = 0;
57 
58  serial_write_reg(p, UART_IER, 0); /* disable all interrupts */
59 
60  /* reset both transmitter and receiver: bits 14,13 = UTRST, URRST */
61  serial_write_reg(p, UART_DAVINCI_PWREMU, pwremu);
62  mdelay(10);
63 
64  pwremu |= (0x3 << 13);
65  pwremu |= 0x1;
66  serial_write_reg(p, UART_DAVINCI_PWREMU, pwremu);
67 
69  serial_write_reg(p, UART_DM646X_SCR,
71 }
72 
74 {
75  int i;
76  char name[16];
77  struct clk *uart_clk;
78  struct davinci_soc_info *soc_info = &davinci_soc_info;
79  struct device *dev = &soc_info->serial_dev->dev;
80  struct plat_serial8250_port *p = dev->platform_data;
81 
82  /*
83  * Make sure the serial ports are muxed on at this point.
84  * You have to mux them off in device drivers later on if not needed.
85  */
86  for (i = 0; p->flags; i++, p++) {
87  if (!(info->enabled_uarts & (1 << i)))
88  continue;
89 
90  sprintf(name, "uart%d", i);
91  uart_clk = clk_get(dev, name);
92  if (IS_ERR(uart_clk)) {
93  printk(KERN_ERR "%s:%d: failed to get UART%d clock\n",
94  __func__, __LINE__, i);
95  continue;
96  }
97 
98  clk_enable(uart_clk);
99  p->uartclk = clk_get_rate(uart_clk);
100 
101  if (!p->membase && p->mapbase) {
102  p->membase = ioremap(p->mapbase, SZ_4K);
103 
104  if (p->membase)
105  p->flags &= ~UPF_IOREMAP;
106  else
107  pr_err("uart regs ioremap failed\n");
108  }
109 
110  if (p->membase && p->type != PORT_AR7)
111  davinci_serial_reset(p);
112  }
113 
114  return platform_device_register(soc_info->serial_dev);
115 }