proc_comm.c

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/* arch/arm/mach-msm/proc_comm.c
 *
 * Copyright (C) 2007-2008 Google, Inc.
 * Author: Brian Swetland <[email protected]>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <mach/msm_iomap.h>

#include "proc_comm.h"

static inline void msm_a2m_int(uint32_t irq)
{
#if defined(CONFIG_ARCH_MSM7X30)
    writel(1 << irq, MSM_GCC_BASE + 0x8);
#else
    writel(1, MSM_CSR_BASE + 0x400 + (irq * 4));
#endif
}

static inline void notify_other_proc_comm(void)
{
    msm_a2m_int(6);
}

#define APP_COMMAND 0x00
#define APP_STATUS  0x04
#define APP_DATA1   0x08
#define APP_DATA2   0x0C

#define MDM_COMMAND 0x10
#define MDM_STATUS  0x14
#define MDM_DATA1   0x18
#define MDM_DATA2   0x1C

static DEFINE_SPINLOCK(proc_comm_lock);

/* The higher level SMD support will install this to
 * provide a way to check for and handle modem restart.
 */
int (*msm_check_for_modem_crash)(void);

/* Poll for a state change, checking for possible
 * modem crashes along the way (so we don't wait
 * forever while the ARM9 is blowing up).
 *
 * Return an error in the event of a modem crash and
 * restart so the msm_proc_comm() routine can restart
 * the operation from the beginning.
 */
static int proc_comm_wait_for(void __iomem *addr, unsigned value)
{
    for (;;) {
        if (readl(addr) == value)
            return 0;

        if (msm_check_for_modem_crash)
            if (msm_check_for_modem_crash())
                return -EAGAIN;
    }
}

int msm_proc_comm(unsigned cmd, unsigned *data1, unsigned *data2)
{
    void __iomem *base = MSM_SHARED_RAM_BASE;
    unsigned long flags;
    int ret;

    spin_lock_irqsave(&proc_comm_lock, flags);

    for (;;) {
        if (proc_comm_wait_for(base + MDM_STATUS, PCOM_READY))
            continue;

        writel(cmd, base + APP_COMMAND);
        writel(data1 ? *data1 : 0, base + APP_DATA1);
        writel(data2 ? *data2 : 0, base + APP_DATA2);

        notify_other_proc_comm();

        if (proc_comm_wait_for(base + APP_COMMAND, PCOM_CMD_DONE))
            continue;

        if (readl(base + APP_STATUS) != PCOM_CMD_FAIL) {
            if (data1)
                *data1 = readl(base + APP_DATA1);
            if (data2)
                *data2 = readl(base + APP_DATA2);
            ret = 0;
        } else {
            ret = -EIO;
        }
        break;
    }

    writel(PCOM_CMD_IDLE, base + APP_COMMAND);

    spin_unlock_irqrestore(&proc_comm_lock, flags);

    return ret;
}

/*
 * We need to wait for the ARM9 to at least partially boot
 * up before we can continue. Since the ARM9 does resource
 * allocation, if we dont' wait we could end up crashing or in
 * and unknown state. This function should be called early to
 * wait on the ARM9.
 */
void __devinit proc_comm_boot_wait(void)
{
    void __iomem *base = MSM_SHARED_RAM_BASE;
 
    proc_comm_wait_for(base + MDM_STATUS, PCOM_READY);
 
}