fbdev: add fb_read/fb_write functions for framebuffers in system RAM
The functions fb_read() and fb_write in fbmem.c assume that the framebuffer
is in IO memory. However, we have 3 drivers (hecubafb, arcfb, and vfb)
where the framebuffer is allocated from system RAM (via vmalloc). Using
__raw_read/__raw_write (fb_readl/fb_writel) for these drivers is
illegal, especially in other platforms.
Create file read and write methods for these types of drivers. These are
named fb_sys_read() and fb_sys_write().
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 6d32726..85d0e87 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -122,6 +122,11 @@
blitting. This is used by drivers that don't provide their own
(accelerated) version and the framebuffer is in system RAM.
+config FB_SYS_FOPS
+ tristate
+ depends on FB
+ default n
+
config FB_DEFERRED_IO
bool
depends on FB
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index fa025e7..6c7b26e 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -21,6 +21,7 @@
obj-$(CONFIG_FB_SYS_FILLRECT) += sysfillrect.o
obj-$(CONFIG_FB_SYS_COPYAREA) += syscopyarea.o
obj-$(CONFIG_FB_SYS_IMAGEBLIT) += sysimgblt.o
+obj-$(CONFIG_FB_SYS_FOPS) += fb_sys_fops.o
obj-$(CONFIG_FB_SVGALIB) += svgalib.o
obj-$(CONFIG_FB_MACMODES) += macmodes.o
obj-$(CONFIG_FB_DDC) += fb_ddc.o
diff --git a/drivers/video/fb_sys_fops.c b/drivers/video/fb_sys_fops.c
new file mode 100644
index 0000000..cf2538d
--- /dev/null
+++ b/drivers/video/fb_sys_fops.c
@@ -0,0 +1,104 @@
+/*
+ * linux/drivers/video/fb_sys_read.c - Generic file operations where
+ * framebuffer is in system RAM
+ *
+ * Copyright (C) 2007 Antonino Daplas <adaplas@pol.net>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of this archive
+ * for more details.
+ *
+ */
+#include <linux/fb.h>
+#include <linux/module.h>
+#include <asm/uaccess.h>
+
+ssize_t fb_sys_read(struct fb_info *info, char __user *buf, size_t count,
+ loff_t *ppos)
+{
+ unsigned long p = *ppos;
+ void *src;
+ int err = 0;
+ unsigned long total_size;
+
+ if (info->state != FBINFO_STATE_RUNNING)
+ return -EPERM;
+
+ total_size = info->screen_size;
+
+ if (total_size == 0)
+ total_size = info->fix.smem_len;
+
+ if (p >= total_size)
+ return 0;
+
+ if (count >= total_size)
+ count = total_size;
+
+ if (count + p > total_size)
+ count = total_size - p;
+
+ src = (void __force *)(info->screen_base + p);
+
+ if (info->fbops->fb_sync)
+ info->fbops->fb_sync(info);
+
+ if (copy_to_user(buf, src, count))
+ err = -EFAULT;
+
+ if (!err)
+ *ppos += count;
+
+ return (err) ? err : count;
+}
+EXPORT_SYMBOL_GPL(fb_sys_read);
+
+ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned long p = *ppos;
+ void *dst;
+ int err = 0;
+ unsigned long total_size;
+
+ if (info->state != FBINFO_STATE_RUNNING)
+ return -EPERM;
+
+ total_size = info->screen_size;
+
+ if (total_size == 0)
+ total_size = info->fix.smem_len;
+
+ if (p > total_size)
+ return -EFBIG;
+
+ if (count > total_size) {
+ err = -EFBIG;
+ count = total_size;
+ }
+
+ if (count + p > total_size) {
+ if (!err)
+ err = -ENOSPC;
+
+ count = total_size - p;
+ }
+
+ dst = (void __force *) (info->screen_base + p);
+
+ if (info->fbops->fb_sync)
+ info->fbops->fb_sync(info);
+
+ if (copy_from_user(dst, buf, count))
+ err = -EFAULT;
+
+ if (!err)
+ *ppos += count;
+
+ return (err) ? err : count;
+}
+EXPORT_SYMBOL_GPL(fb_sys_write);
+
+MODULE_AUTHOR("Antonino Daplas <adaplas@pol.net>");
+MODULE_DESCRIPTION("Generic file read (fb in system RAM)");
+MODULE_LICENSE("GPL");