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
  23 #include "proc_comm.h"
  24
  25 static inline void msm_a2m_int(uint32_t irq)
  26 {
  27 #if defined(CONFIG_ARCH_MSM7X30)
  28         writel(1 << irq, MSM_GCC_BASE + 0x8);
  29 #else
  30         writel(1, MSM_CSR_BASE + 0x400 + (irq * 4));
  31 #endif
  32 }
  33
  34 static inline void notify_other_proc_comm(void)
  35 {
  36         msm_a2m_int(6);
  37 }
  38
  39 #define APP_COMMAND 0x00
  40 #define APP_STATUS  0x04
  41 #define APP_DATA1   0x08
  42 #define APP_DATA2   0x0C
  43
  44 #define MDM_COMMAND 0x10
  45 #define MDM_STATUS  0x14
  46 #define MDM_DATA1   0x18
  47 #define MDM_DATA2   0x1C
  48
  49 static DEFINE_SPINLOCK(proc_comm_lock);
  50
  51 /* The higher level SMD support will install this to
  52  * provide a way to check for and handle modem restart.
  53  */
  54 int (*msm_check_for_modem_crash)(void);
  55
  56 /* Poll for a state change, checking for possible
  57  * modem crashes along the way (so we don't wait
  58  * forever while the ARM9 is blowing up).
  59  *
  60  * Return an error in the event of a modem crash and
  61  * restart so the msm_proc_comm() routine can restart
  62  * the operation from the beginning.
  63  */
  64 static int proc_comm_wait_for(void __iomem *addr, unsigned value)
  65 {
  66         for (;;) {
  67                 if (readl(addr) == value)
  68                         return 0;
  69
  70                 if (msm_check_for_modem_crash)
  71                         if (msm_check_for_modem_crash())
  72                                 return -EAGAIN;
  73         }
  74 }
  75
  76 int msm_proc_comm(unsigned cmd, unsigned *data1, unsigned *data2)
  77 {
  78         void __iomem *base = MSM_SHARED_RAM_BASE;
  79         unsigned long flags;
  80         int ret;
  81
  82         spin_lock_irqsave(&proc_comm_lock, flags);
  83
  84         for (;;) {
  85                 if (proc_comm_wait_for(base + MDM_STATUS, PCOM_READY))
  86                         continue;
  87
  88                 writel(cmd, base + APP_COMMAND);
  89                 writel(data1 ? *data1 : 0, base + APP_DATA1);
  90                 writel(data2 ? *data2 : 0, base + APP_DATA2);
  91
  92                 notify_other_proc_comm();
  93
  94                 if (proc_comm_wait_for(base + APP_COMMAND, PCOM_CMD_DONE))
  95                         continue;
  96
  97                 if (readl(base + APP_STATUS) != PCOM_CMD_FAIL) {
  98                         if (data1)
  99                                 *data1 = readl(base + APP_DATA1);
 100                         if (data2)
 101                                 *data2 = readl(base + APP_DATA2);
 102                         ret = 0;
 103                 } else {
 104                         ret = -EIO;
 105                 }
 106                 break;
 107         }
 108
 109         writel(PCOM_CMD_IDLE, base + APP_COMMAND);
 110
 111         spin_unlock_irqrestore(&proc_comm_lock, flags);
 112
 113         return ret;
 114 }
 115
 116 /*
 117  * We need to wait for the ARM9 to at least partially boot
 118  * up before we can continue. Since the ARM9 does resource
 119  * allocation, if we dont' wait we could end up crashing or in
 120  * and unknown state. This function should be called early to
 121  * wait on the ARM9.
 122  */
 123 void proc_comm_boot_wait(void)
 124 {
 125         void __iomem *base = MSM_SHARED_RAM_BASE;
 126
 127         proc_comm_wait_for(base + MDM_STATUS, PCOM_READY);
 128
 129 }