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: Sreedhara DS <sreedhara.ds@intel.com>
[Extensive clean up and debug]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 133 insertions, 0 deletions

diff --git a/drivers/platform/x86/intel_scu_ipcutil.c b/drivers/platform/x86/intel_scu_ipcutil.c
new file mode 100644
index 000000000000..ba3231d0819e
--- /dev/null
+++ b/drivers/platform/x86/intel_scu_ipcutil.c
@@ -0,0 +1,133 @@
+/*
+ * 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>");