arch/arm/mach-msm/proc_comm.c

   1 /* arch/arm/mach-msm/proc_comm.c
   2  *
   3  * Copyright (C) 2007-2008 Google, Inc.
   4  * Author: Brian Swetland <swetland@google.com>
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  */
  16
  17 #include <linux/delay.h>
  18 #include <linux/errno.h>
  19 #include <linux/io.h>
  20 #include <linux/spinlock.h>
  21 #include <mach/msm_iomap.h>
  22 #include <mach/system.h>
  23
  24 #include "proc_comm.h"
  25
  26 #define MSM_A2M_INT(n) (MSM_CSR_BASE + 0x400 + (n) * 4)
  27
  28 static inline void notify_other_proc_comm(void)
  29 {
  30         writel(1, MSM_A2M_INT(6));
  31 }
  32
  33 #define APP_COMMAND 0x00
  34 #define APP_STATUS  0x04
  35 #define APP_DATA1   0x08
  36 #define APP_DATA2   0x0C
  37
  38 #define MDM_COMMAND 0x10
  39 #define MDM_STATUS  0x14
  40 #define MDM_DATA1   0x18
  41 #define MDM_DATA2   0x1C
  42
  43 static DEFINE_SPINLOCK(proc_comm_lock);
  44
  45 /* The higher level SMD support will install this to
  46  * provide a way to check for and handle modem restart.
  47  */
  48 int (*msm_check_for_modem_crash)(void);
  49
  50 /* Poll for a state change, checking for possible
  51  * modem crashes along the way (so we don't wait
  52  * forever while the ARM9 is blowing up).
  53  *
  54  * Return an error in the event of a modem crash and
  55  * restart so the msm_proc_comm() routine can restart
  56  * the operation from the beginning.
  57  */
  58 static int proc_comm_wait_for(void __iomem *addr, unsigned value)
  59 {
  60         for (;;) {
  61                 if (readl(addr) == value)
  62                         return 0;
  63
  64                 if (msm_check_for_modem_crash)
  65                         if (msm_check_for_modem_crash())
  66                                 return -EAGAIN;
  67         }
  68 }
  69
  70 int msm_proc_comm(unsigned cmd, unsigned *data1, unsigned *data2)
  71 {
  72         void __iomem *base = MSM_SHARED_RAM_BASE;
  73         unsigned long flags;
  74         int ret;
  75
  76         spin_lock_irqsave(&proc_comm_lock, flags);
  77
  78         for (;;) {
  79                 if (proc_comm_wait_for(base + MDM_STATUS, PCOM_READY))
  80                         continue;
  81
  82                 writel(cmd, base + APP_COMMAND);
  83                 writel(data1 ? *data1 : 0, base + APP_DATA1);
  84                 writel(data2 ? *data2 : 0, base + APP_DATA2);
  85
  86                 notify_other_proc_comm();
  87
  88                 if (proc_comm_wait_for(base + APP_COMMAND, PCOM_CMD_DONE))
  89                         continue;
  90
  91                 if (readl(base + APP_STATUS) != PCOM_CMD_FAIL) {
  92                         if (data1)
  93                                 *data1 = readl(base + APP_DATA1);
  94                         if (data2)
  95                                 *data2 = readl(base + APP_DATA2);
  96                         ret = 0;
  97                 } else {
  98                         ret = -EIO;
  99                 }
 100                 break;
 101         }
 102
 103         writel(PCOM_CMD_IDLE, base + APP_COMMAND);
 104
 105         spin_unlock_irqrestore(&proc_comm_lock, flags);
 106
 107         return ret;
 108 }
 109
 110