vc_mem: Add vc_mem driver for querying firmware memory addresses

Signed-off-by: popcornmix <popcornmix@gmail.com>

BCM270x: Move vc_mem

Make the vc_mem module available for ARCH_BCM2835 by moving it.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

char: vc_mem: Fix up compat ioctls for 64bit kernel

compat_ioctl wasn't defined, so 32bit user/64bit kernel
always failed.
VC_MEM_IOC_MEM_PHYS_ADDR was defined with parameter size
unsigned long, so the ioctl cmd changes between sizes.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>

char: vc_mem: Fix all coding style issues.

Cleans up all checkpatch errors in vc_mem.c and vc_mem.h
No functional change to the code.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>

char: vc_mem: Delete dead code

There are no error exists once device_create has succeeded, and
therefore no need to call device_destroy from vc_mem_init.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

drivers/char/broadcom/Kconfig

@@ -0,0 +1,18 @@
+#
+# Broadcom char driver config
+#
+
+menuconfig BRCM_CHAR_DRIVERS
+	bool "Broadcom Char Drivers"
+	help
+	  Broadcom's char drivers
+
+if BRCM_CHAR_DRIVERS
+
+config BCM2708_VCMEM
+	bool "Videocore Memory"
+        default y
+        help
+          Helper for videocore memory access and total size allocation.
+
+endif

drivers/char/broadcom/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_BCM2708_VCMEM)	+= vc_mem.o

drivers/char/broadcom/vc_mem.c

@@ -0,0 +1,373 @@
+/*
+ * Copyright 2010 - 2011 Broadcom Corporation.  All rights reserved.
+ *
+ * Unless you and Broadcom execute a separate written software license
+ * agreement governing use of this software, this software is licensed to you
+ * under the terms of the GNU General Public License version 2, available at
+ * http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
+ *
+ * Notwithstanding the above, under no circumstances may you combine this
+ * software in any way with any other Broadcom software provided under a
+ * license other than the GPL, without Broadcom's express prior written
+ * consent.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/dma-mapping.h>
+#include <linux/broadcom/vc_mem.h>
+
+#define DRIVER_NAME  "vc-mem"
+
+/* Device (/dev) related variables */
+static dev_t vc_mem_devnum;
+static struct class *vc_mem_class;
+static struct cdev vc_mem_cdev;
+static int vc_mem_inited;
+
+#ifdef CONFIG_DEBUG_FS
+static struct dentry *vc_mem_debugfs_entry;
+#endif
+
+/*
+ * Videocore memory addresses and size
+ *
+ * Drivers that wish to know the videocore memory addresses and sizes should
+ * use these variables instead of the MM_IO_BASE and MM_ADDR_IO defines in
+ * headers. This allows the other drivers to not be tied down to a a certain
+ * address/size at compile time.
+ *
+ * In the future, the goal is to have the videocore memory virtual address and
+ * size be calculated at boot time rather than at compile time. The decision of
+ * where the videocore memory resides and its size would be in the hands of the
+ * bootloader (and/or kernel). When that happens, the values of these variables
+ * would be calculated and assigned in the init function.
+ */
+/* In the 2835 VC in mapped above ARM, but ARM has full access to VC space */
+unsigned long mm_vc_mem_phys_addr;
+EXPORT_SYMBOL(mm_vc_mem_phys_addr);
+unsigned int mm_vc_mem_size;
+EXPORT_SYMBOL(mm_vc_mem_size);
+unsigned int mm_vc_mem_base;
+EXPORT_SYMBOL(mm_vc_mem_base);
+
+static uint phys_addr;
+static uint mem_size;
+static uint mem_base;
+
+static int
+vc_mem_open(struct inode *inode, struct file *file)
+{
+	(void)inode;
+
+	pr_debug("%s: called file = 0x%p\n", __func__, file);
+
+	return 0;
+}
+
+static int
+vc_mem_release(struct inode *inode, struct file *file)
+{
+	(void)inode;
+
+	pr_debug("%s: called file = 0x%p\n", __func__, file);
+
+	return 0;
+}
+
+static void
+vc_mem_get_size(void)
+{
+}
+
+static void
+vc_mem_get_base(void)
+{
+}
+
+int
+vc_mem_get_current_size(void)
+{
+	return mm_vc_mem_size;
+}
+EXPORT_SYMBOL_GPL(vc_mem_get_current_size);
+
+static long
+vc_mem_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int rc = 0;
+
+	(void) cmd;
+	(void) arg;
+
+	pr_debug("%s: called file = 0x%p, cmd %08x\n", __func__, file, cmd);
+
+	switch (cmd) {
+	case VC_MEM_IOC_MEM_PHYS_ADDR:
+		{
+			pr_debug("%s: VC_MEM_IOC_MEM_PHYS_ADDR=0x%p\n",
+				__func__, (void *)mm_vc_mem_phys_addr);
+
+			if (copy_to_user((void *)arg, &mm_vc_mem_phys_addr,
+					 sizeof(mm_vc_mem_phys_addr))) {
+				rc = -EFAULT;
+			}
+			break;
+		}
+	case VC_MEM_IOC_MEM_SIZE:
+		{
+			/* Get the videocore memory size first */
+			vc_mem_get_size();
+
+			pr_debug("%s: VC_MEM_IOC_MEM_SIZE=%x\n", __func__,
+				 mm_vc_mem_size);
+
+			if (copy_to_user((void *)arg, &mm_vc_mem_size,
+					 sizeof(mm_vc_mem_size))) {
+				rc = -EFAULT;
+			}
+			break;
+		}
+	case VC_MEM_IOC_MEM_BASE:
+		{
+			/* Get the videocore memory base */
+			vc_mem_get_base();
+
+			pr_debug("%s: VC_MEM_IOC_MEM_BASE=%x\n", __func__,
+				 mm_vc_mem_base);
+
+			if (copy_to_user((void *)arg, &mm_vc_mem_base,
+					 sizeof(mm_vc_mem_base))) {
+				rc = -EFAULT;
+			}
+			break;
+		}
+	case VC_MEM_IOC_MEM_LOAD:
+		{
+			/* Get the videocore memory base */
+			vc_mem_get_base();
+
+			pr_debug("%s: VC_MEM_IOC_MEM_LOAD=%x\n", __func__,
+				mm_vc_mem_base);
+
+			if (copy_to_user((void *)arg, &mm_vc_mem_base,
+					 sizeof(mm_vc_mem_base))) {
+				rc = -EFAULT;
+			}
+			break;
+		}
+	default:
+		{
+			return -ENOTTY;
+		}
+	}
+	pr_debug("%s: file = 0x%p returning %d\n", __func__, file, rc);
+
+	return rc;
+}
+
+#ifdef CONFIG_COMPAT
+static long
+vc_mem_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int rc = 0;
+
+	switch (cmd) {
+	case VC_MEM_IOC_MEM_PHYS_ADDR32:
+		pr_debug("%s: VC_MEM_IOC_MEM_PHYS_ADDR32=0x%p\n",
+			 __func__, (void *)mm_vc_mem_phys_addr);
+
+		/* This isn't correct, but will cover us for now as
+		 * VideoCore is 32bit only.
+		 */
+		if (copy_to_user((void *)arg, &mm_vc_mem_phys_addr,
+				 sizeof(compat_ulong_t)))
+			rc = -EFAULT;
+
+		break;
+
+	default:
+		rc = vc_mem_ioctl(file, cmd, arg);
+		break;
+	}
+
+	return rc;
+}
+#endif
+
+static int
+vc_mem_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	int rc = 0;
+	unsigned long length = vma->vm_end - vma->vm_start;
+	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+
+	pr_debug("%s: vm_start = 0x%08lx vm_end = 0x%08lx vm_pgoff = 0x%08lx\n",
+		 __func__, (long)vma->vm_start, (long)vma->vm_end,
+		 (long)vma->vm_pgoff);
+
+	if (offset + length > mm_vc_mem_size) {
+		pr_err("%s: length %ld is too big\n", __func__, length);
+		return -EINVAL;
+	}
+	/* Do not cache the memory map */
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+	rc = remap_pfn_range(vma, vma->vm_start,
+			     (mm_vc_mem_phys_addr >> PAGE_SHIFT) +
+			     vma->vm_pgoff, length, vma->vm_page_prot);
+	if (rc)
+		pr_err("%s: remap_pfn_range failed (rc=%d)\n", __func__, rc);
+
+	return rc;
+}
+
+/* File Operations for the driver. */
+static const struct file_operations vc_mem_fops = {
+	.owner = THIS_MODULE,
+	.open = vc_mem_open,
+	.release = vc_mem_release,
+	.unlocked_ioctl = vc_mem_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = vc_mem_compat_ioctl,
+#endif
+	.mmap = vc_mem_mmap,
+};
+
+#ifdef CONFIG_DEBUG_FS
+static void vc_mem_debugfs_deinit(void)
+{
+	debugfs_remove_recursive(vc_mem_debugfs_entry);
+	vc_mem_debugfs_entry = NULL;
+}
+
+
+static int vc_mem_debugfs_init(
+	struct device *dev)
+{
+	vc_mem_debugfs_entry = debugfs_create_dir(DRIVER_NAME, NULL);
+	if (!vc_mem_debugfs_entry) {
+		dev_warn(dev, "could not create debugfs entry\n");
+		return -EFAULT;
+	}
+
+	debugfs_create_x32("vc_mem_phys_addr",
+				0444,
+				vc_mem_debugfs_entry,
+				(u32 *)&mm_vc_mem_phys_addr);
+	debugfs_create_x32("vc_mem_size",
+				0444,
+				vc_mem_debugfs_entry,
+				(u32 *)&mm_vc_mem_size);
+	debugfs_create_x32("vc_mem_base",
+				0444,
+				vc_mem_debugfs_entry,
+				(u32 *)&mm_vc_mem_base);
+
+	return 0;
+}
+
+#endif /* CONFIG_DEBUG_FS */
+
+/* Module load/unload functions */
+
+static int __init
+vc_mem_init(void)
+{
+	int rc = -EFAULT;
+	struct device *dev;
+
+	pr_debug("%s: called\n", __func__);
+
+	mm_vc_mem_phys_addr = phys_addr;
+	mm_vc_mem_size = mem_size;
+	mm_vc_mem_base = mem_base;
+
+	vc_mem_get_size();
+
+	pr_info("vc-mem: phys_addr:0x%08lx mem_base=0x%08x mem_size:0x%08x(%u MiB)\n",
+		mm_vc_mem_phys_addr, mm_vc_mem_base, mm_vc_mem_size,
+		mm_vc_mem_size / (1024 * 1024));
+
+	rc = alloc_chrdev_region(&vc_mem_devnum, 0, 1, DRIVER_NAME);
+	if (rc < 0) {
+		pr_err("%s: alloc_chrdev_region failed (rc=%d)\n",
+		       __func__, rc);
+		goto out_err;
+	}
+
+	cdev_init(&vc_mem_cdev, &vc_mem_fops);
+	rc = cdev_add(&vc_mem_cdev, vc_mem_devnum, 1);
+	if (rc) {
+		pr_err("%s: cdev_add failed (rc=%d)\n", __func__, rc);
+		goto out_unregister;
+	}
+
+	vc_mem_class = class_create(THIS_MODULE, DRIVER_NAME);
+	if (IS_ERR(vc_mem_class)) {
+		rc = PTR_ERR(vc_mem_class);
+		pr_err("%s: class_create failed (rc=%d)\n", __func__, rc);
+		goto out_cdev_del;
+	}
+
+	dev = device_create(vc_mem_class, NULL, vc_mem_devnum, NULL,
+			    DRIVER_NAME);
+	if (IS_ERR(dev)) {
+		rc = PTR_ERR(dev);
+		pr_err("%s: device_create failed (rc=%d)\n", __func__, rc);
+		goto out_class_destroy;
+	}
+
+#ifdef CONFIG_DEBUG_FS
+	/* don't fail if the debug entries cannot be created */
+	vc_mem_debugfs_init(dev);
+#endif
+
+	vc_mem_inited = 1;
+	return 0;
+
+out_class_destroy:
+	class_destroy(vc_mem_class);
+	vc_mem_class = NULL;
+
+out_cdev_del:
+	cdev_del(&vc_mem_cdev);
+
+out_unregister:
+	unregister_chrdev_region(vc_mem_devnum, 1);
+
+out_err:
+	return -1;
+}
+
+static void __exit
+vc_mem_exit(void)
+{
+	pr_debug("%s: called\n", __func__);
+
+	if (vc_mem_inited) {
+#if CONFIG_DEBUG_FS
+		vc_mem_debugfs_deinit();
+#endif
+		device_destroy(vc_mem_class, vc_mem_devnum);
+		class_destroy(vc_mem_class);
+		cdev_del(&vc_mem_cdev);
+		unregister_chrdev_region(vc_mem_devnum, 1);
+	}
+}
+
+module_init(vc_mem_init);
+module_exit(vc_mem_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Broadcom Corporation");
+
+module_param(phys_addr, uint, 0644);
+module_param(mem_size, uint, 0644);
+module_param(mem_base, uint, 0644);