intel_scu_ipc: Utility driver for intel scu ipc

This driver implements ioctl and interfaces with intel scu ipc driver. It
is used to access pmic/msic registers from user space and firmware update
utility.
Signed-off-by: NSreedhara DS <sreedhara.ds@intel.com>
[Extensive clean up and debug]
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NMatthew Garrett <mjg@redhat.com>

drivers/platform/x86/Kconfig

@@ -576,6 +576,15 @@ config INTEL_SCU_IPC
 	  some embedded Intel x86 platforms. This is not needed for PC-type
 	  machines.
 
+config INTEL_SCU_IPC_UTIL
+	tristate "Intel SCU IPC utility driver"
+	depends on INTEL_SCU_IPC
+	default y
+	---help---
+	  The IPC Util driver provides an interface with the SCU enabling
+	  low level access for debug work and updating the firmware. Say
+	  N unless you will be doing this on an Intel MID platform.
+
 config GPIO_INTEL_PMIC
 	bool "Intel PMIC GPIO support"
 	depends on INTEL_SCU_IPC && GPIOLIB

drivers/platform/x86/Makefile

@@ -28,6 +28,7 @@ obj-$(CONFIG_TOPSTAR_LAPTOP)	+= topstar-laptop.o
 obj-$(CONFIG_ACPI_TOSHIBA)	+= toshiba_acpi.o
 obj-$(CONFIG_TOSHIBA_BT_RFKILL)	+= toshiba_bluetooth.o
 obj-$(CONFIG_INTEL_SCU_IPC)	+= intel_scu_ipc.o
+obj-$(CONFIG_INTEL_SCU_IPC_UTIL)+= intel_scu_ipcutil.o
 obj-$(CONFIG_RAR_REGISTER)	+= intel_rar_register.o
 obj-$(CONFIG_INTEL_IPS)		+= intel_ips.o
 obj-$(CONFIG_GPIO_INTEL_PMIC)	+= intel_pmic_gpio.o

drivers/platform/x86/intel_scu_ipc.c

@@ -497,7 +497,7 @@ int intel_scu_ipc_i2c_cntrl(u32 addr, u32 *data)
 			"intel_scu_ipc: I2C INVALID_CMD = 0x%x\n", cmd);
 
 		mutex_unlock(&ipclock);
-		return -1;
+		return -EIO;
 	}
 	mutex_unlock(&ipclock);
 	return 0;
@@ -642,7 +642,7 @@ int intel_scu_ipc_fw_update(u8 *buffer, u32 length)
 
 	if (status == IPC_FW_UPDATE_SUCCESS)
 		return 0;
-	return -1;
+	return -EIO;
 }
 EXPORT_SYMBOL(intel_scu_ipc_fw_update);
 

drivers/platform/x86/intel_scu_ipcutil.c

+/*
+ * intel_scu_ipc.c: Driver for the Intel SCU IPC mechanism
+ *
+ * (C) Copyright 2008-2010 Intel Corporation
+ * Author: Sreedhara DS (sreedhara.ds@intel.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ *
+ * This driver provides ioctl interfaces to call intel scu ipc driver api
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/fcntl.h>
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <asm/intel_scu_ipc.h>
+
+static u32 major;
+
+#define MAX_FW_SIZE 264192
+
+/* ioctl commnds */
+#define	INTE_SCU_IPC_REGISTER_READ	0
+#define INTE_SCU_IPC_REGISTER_WRITE	1
+#define INTE_SCU_IPC_REGISTER_UPDATE	2
+#define INTE_SCU_IPC_FW_UPDATE		0xA2
+
+struct scu_ipc_data {
+	u32     count;  /* No. of registers */
+	u16     addr[5]; /* Register addresses */
+	u8      data[5]; /* Register data */
+	u8      mask; /* Valid for read-modify-write */
+};
+
+/**
+ *	scu_reg_access		-	implement register access ioctls
+ *	@cmd: command we are doing (read/write/update)
+ *	@data: kernel copy of ioctl data
+ *
+ *	Allow the user to perform register accesses on the SCU via the
+ *	kernel interface
+ */
+
+static int scu_reg_access(u32 cmd, struct scu_ipc_data  *data)
+{
+	int count = data->count;
+
+	if (count == 0 || count == 3 || count > 4)
+		return -EINVAL;
+
+	switch (cmd) {
+	case INTE_SCU_IPC_REGISTER_READ:
+		return intel_scu_ipc_readv(data->addr, data->data, count);
+	case INTE_SCU_IPC_REGISTER_WRITE:
+		return intel_scu_ipc_writev(data->addr, data->data, count);
+	case INTE_SCU_IPC_REGISTER_UPDATE:
+		return intel_scu_ipc_update_register(data->addr[0],
+						    data->data[0], data->mask);
+	default:
+		return -ENOTTY;
+	}
+}
+
+/**
+ *	scu_ipc_ioctl		-	control ioctls for the SCU
+ *	@fp: file handle of the SCU device
+ *	@cmd: ioctl coce
+ *	@arg: pointer to user passed structure
+ *
+ *	Support the I/O and firmware flashing interfaces of the SCU
+ */
+static long scu_ipc_ioctl(struct file *fp, unsigned int cmd,
+							unsigned long arg)
+{
+	int ret;
+	struct scu_ipc_data  data;
+	void __user *argp = (void __user *)arg;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	if (cmd == INTE_SCU_IPC_FW_UPDATE) {
+			u8 *fwbuf = kmalloc(MAX_FW_SIZE, GFP_KERNEL);
+			if (fwbuf == NULL)
+				return -ENOMEM;
+			if (copy_from_user(fwbuf, (u8 *)arg, MAX_FW_SIZE)) {
+				kfree(fwbuf);
+				return -EFAULT;
+			}
+			ret = intel_scu_ipc_fw_update(fwbuf, MAX_FW_SIZE);
+			kfree(fwbuf);
+			return ret;
+	} else {
+		if (copy_from_user(&data, argp, sizeof(struct scu_ipc_data)))
+			return -EFAULT;
+		ret = scu_reg_access(cmd, &data);
+		if (ret < 0)
+			return ret;
+		if (copy_to_user(argp, &data, sizeof(struct scu_ipc_data)))
+			return -EFAULT;
+		return 0;
+	}
+}
+
+static const struct file_operations scu_ipc_fops = {
+	.unlocked_ioctl = scu_ipc_ioctl,
+};
+
+static int __init ipc_module_init(void)
+{
+	return register_chrdev(0, "intel_mid_scu", &scu_ipc_fops);
+}
+
+static void __exit ipc_module_exit(void)
+{
+	unregister_chrdev(major, "intel_mid_scu");
+}
+
+module_init(ipc_module_init);
+module_exit(ipc_module_exit);
+
+MODULE_LICENSE("GPL V2");
+MODULE_DESCRIPTION("Utility driver for intel scu ipc");
+MODULE_AUTHOR("Sreedhara <sreedhara.ds@intel.com>");