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 static inline void msm_a2m_int(uint32_t irq)
  27 {
  28 #if defined(CONFIG_ARCH_MSM7X30)
  29         writel(1 << irq, MSM_GCC_BASE + 0x8);
  30 #else
  31         writel(1, MSM_CSR_BASE + 0x400 + (irq * 4));
  32 #endif
  33 }
  34
  35 static inline void notify_other_proc_comm(void)
  36 {
  37         msm_a2m_int(6);
  38 }
  39
  40 #define APP_COMMAND 0x00
  41 #define APP_STATUS  0x04
  42 #define APP_DATA1   0x08
  43 #define APP_DATA2   0x0C
  44
  45 #define MDM_COMMAND 0x10
  46 #define MDM_STATUS  0x14
  47 #define MDM_DATA1   0x18
  48 #define MDM_DATA2   0x1C
  49
  50 static DEFINE_SPINLOCK(proc_comm_lock);
  51
  52 /* The higher level SMD support will install this to
  53  * provide a way to check for and handle modem restart.
  54  */
  55 int (*msm_check_for_modem_crash)(void);
  56
  57 /* Poll for a state change, checking for possible
  58  * modem crashes along the way (so we don't wait
  59  * forever while the ARM9 is blowing up).
  60  *
  61  * Return an error in the event of a modem crash and
  62  * restart so the msm_proc_comm() routine can restart
  63  * the operation from the beginning.
  64  */
  65 static int proc_comm_wait_for(void __iomem *addr, unsigned value)
  66 {
  67         for (;;) {
  68                 if (readl(addr) == value)
  69                         return 0;
  70
  71                 if (msm_check_for_modem_crash)
  72                         if (msm_check_for_modem_crash())
  73                                 return -EAGAIN;
  74         }
  75 }
  76
  77 int msm_proc_comm(unsigned cmd, unsigned *data1, unsigned *data2)
  78 {
  79         void __iomem *base = MSM_SHARED_RAM_BASE;
  80         unsigned long flags;
  81         int ret;
  82
  83         spin_lock_irqsave(&proc_comm_lock, flags);
  84
  85         for (;;) {
  86                 if (proc_comm_wait_for(base + MDM_STATUS, PCOM_READY))
  87                         continue;
  88
  89                 writel(cmd, base + APP_COMMAND);
  90                 writel(data1 ? *data1 : 0, base + APP_DATA1);
  91                 writel(data2 ? *data2 : 0, base + APP_DATA2);
  92
  93                 notify_other_proc_comm();
  94
  95                 if (proc_comm_wait_for(base + APP_COMMAND, PCOM_CMD_DONE))
  96                         continue;
  97
  98                 if (readl(base + APP_STATUS) != PCOM_CMD_FAIL) {
  99                         if (data1)
 100                                 *data1 = readl(base + APP_DATA1);
 101                         if (data2)
 102                                 *data2 = readl(base + APP_DATA2);
 103                         ret = 0;
 104                 } else {
 105                         ret = -EIO;
 106                 }
 107                 break;
 108         }
 109
 110         writel(PCOM_CMD_IDLE, base + APP_COMMAND);
 111
 112         spin_unlock_irqrestore(&proc_comm_lock, flags);
 113
 114         return ret;
 115 }
 116
 117 /*
 118  * We need to wait for the ARM9 to at least partially boot
 119  * up before we can continue. Since the ARM9 does resource
 120  * allocation, if we dont' wait we could end up crashing or in
 121  * and unknown state. This function should be called early to
 122  * wait on the ARM9.
 123  */
 124 void __init proc_comm_boot_wait(void)
 125 {
 126         void __iomem *base = MSM_SHARED_RAM_BASE;
 127
 128         proc_comm_wait_for(base + MDM_STATUS, PCOM_READY);
 129
 130 }