[ARM] msm: add proc_comm support, necessary for clock and power control

The proc_comm protocol is the lowest level protocol available for
communicating with the modem core.  It provides access to clock and
power control, among other things, and is safe for use from atomic
contexts, unlike the higher level SMD and RPC transports.

Signed-off-by: Brian Swetland <swetland@google.com>

1 files changed, 110 insertions, 0 deletions

diff --git a/arch/arm/mach-msm/proc_comm.c b/arch/arm/mach-msm/proc_comm.c
new file mode 100644
index 0000000..915ee70
--- /dev/null
+++ b/arch/arm/mach-msm/proc_comm.c
@@ -0,0 +1,110 @@
+/* arch/arm/mach-msm/proc_comm.c
+ *
+ * Copyright (C) 2007-2008 Google, Inc.
+ * Author: Brian Swetland <swetland@google.com>
+ *
+ * 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 <mach/system.h>
+
+#include "proc_comm.h"
+
+#define MSM_A2M_INT(n) (MSM_CSR_BASE + 0x400 + (n) * 4)
+
+static inline void notify_other_proc_comm(void)
+{
+	writel(1, 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;
+}
+
+