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SubjectRE: [PATCH 07/20] video: msm: Allow users to request a larger x and y virtual fb


> -----Original Message-----
> From: linux-fbdev-owner@vger.kernel.org [mailto:linux-fbdev-
> owner@vger.kernel.org] On Behalf Of Carl Vanderlip
> Sent: Saturday, March 19, 2011 3:26 AM
> To: David Brown; Daniel Walker; Bryan Huntsman
> Cc: Brian Swetland; Dima Zavin; Rebecca Schultz Zavin; Colin Cross; linux-
> fbdev@vger.kernel.org; Carl Vanderlip; linux-arm-
> kernel@lists.infradead.org; linux-arm-msm@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: [PATCH 07/20] video: msm: Allow users to request a larger x and y
> virtual fb
>
> As long as the total size fits inside the memory allocated to the
> framebuffer
> users can request a larger size. This change allows users to request a
> triple
> buffered fb.
>
> Authors:
> Dima Zavin <dima@android.com>
> Rebecca Schultz Zavin <rebecca@android.com>
> Colin Cross <ccross@android.com>
>
> Signed-off-by: Carl Vanderlip <carlv@codeaurora.org>
> ---
> drivers/video/msm/msm_fb.c | 63 ++++++++++++++++++++++++++++++++++-----
> ----
> 1 files changed, 50 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/video/msm/msm_fb.c b/drivers/video/msm/msm_fb.c
> index 04d0067..6af8b41 100644
> --- a/drivers/video/msm/msm_fb.c
> +++ b/drivers/video/msm/msm_fb.c
> @@ -53,6 +53,9 @@ do { \
> printk(KERN_INFO "msmfb: "fmt, ##args); \
> } while (0)
>
> +#define BITS_PER_PIXEL(info) (info->fb->var.bits_per_pixel)
> +#define BYTES_PER_PIXEL(info) (info->fb->var.bits_per_pixel >> 3)
> +
> static int msmfb_debug_mask;
> module_param_named(msmfb_debug_mask, msmfb_debug_mask, int,
> S_IRUGO | S_IWUSR | S_IWGRP);
> @@ -161,9 +164,10 @@ static int msmfb_start_dma(struct msmfb_info *msmfb)
> }
> spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
>
> - addr = ((msmfb->xres * (yoffset + y) + x) * 2);
> + addr = ((msmfb->xres * (yoffset + y) + x) * BYTES_PER_PIXEL(msmfb));
> mdp->dma(mdp, addr + msmfb->fb->fix.smem_start,
> - msmfb->xres * 2, w, h, x, y, &msmfb->dma_callback,
> + msmfb->xres * BYTES_PER_PIXEL(msmfb), w, h, x, y,
> + &msmfb->dma_callback,
> panel->interface_type);
> return 0;
> error:
> @@ -323,14 +327,46 @@ error:
>
> static int msmfb_check_var(struct fb_var_screeninfo *var, struct fb_info
> *info)
> {
> + u32 size;
> +
> if ((var->xres != info->var.xres) ||
> (var->yres != info->var.yres) ||
> - (var->xres_virtual != info->var.xres_virtual) ||
> - (var->yres_virtual != info->var.yres_virtual) ||
> (var->xoffset != info->var.xoffset) ||
> (var->bits_per_pixel != info->var.bits_per_pixel) ||
> (var->grayscale != info->var.grayscale))
> return -EINVAL;
> +
> + size = var->xres_virtual * var->yres_virtual *
> + (var->bits_per_pixel >> 3);

How about defining a new macro BYTES_PER_PIXEL_VAR for fb_var_screeninfo also? That would make code more readable.

> + if (size > info->fix.smem_len)
> + return -EINVAL;
> + return 0;
> +}
> +
> +static int msmfb_set_par(struct fb_info *info)
> +{
> + struct fb_var_screeninfo *var = &info->var;
> + struct fb_fix_screeninfo *fix = &info->fix;
> +
> + /* we only support RGB ordering for now */
> + if (var->bits_per_pixel == 32 || var->bits_per_pixel == 24) {
> + var->red.offset = 0;
> + var->red.length = 8;
> + var->green.offset = 8;
> + var->green.length = 8;
> + var->blue.offset = 16;
> + var->blue.length = 8;

var->red is a fb_bitfield variable.
It provides offset, length and msb_right.

struct fb_bitfield {
__u32 offset; /* beginning of bitfield */
__u32 length; /* length of bitfield */
__u32 msb_right; /* != 0 : Most significant bit is */
/* right */
}
Please don't keep msb_right unassigned.

> + } else if (var->bits_per_pixel == 16) {
> + var->red.offset = 11;
> + var->red.length = 5;
> + var->green.offset = 5;
> + var->green.length = 6;
> + var->blue.offset = 0;
> + var->blue.length = 5;
> + } else
> + return -1;

Please use standard error code provided by Linux kernel -EINVAL
(-22 Invalid argument)

> + fix->line_length = var->xres * var->bits_per_pixel / 8;
Why to divide by 8? Atleast use >>3, bitwise operations that would take less cpu cycles)
As I stated earlier define a new macro for var also.

> +
> return 0;
> }
>
> @@ -427,6 +463,7 @@ static struct fb_ops msmfb_ops = {
> .fb_open = msmfb_open,
> .fb_release = msmfb_release,
> .fb_check_var = msmfb_check_var,
> + .fb_set_par = msmfb_set_par,
> .fb_pan_display = msmfb_pan_display,
> .fb_fillrect = msmfb_fillrect,
> .fb_copyarea = msmfb_copyarea,
> @@ -438,8 +475,6 @@ static unsigned PP[16];
>
>
>
> -#define BITS_PER_PIXEL 16
> -
> static void setup_fb_info(struct msmfb_info *msmfb)
> {
> struct fb_info *fb_info = msmfb->fb;
> @@ -462,7 +497,7 @@ static void setup_fb_info(struct msmfb_info *msmfb)
> fb_info->var.height = msmfb->panel->fb_data->height;
> fb_info->var.xres_virtual = msmfb->xres;
> fb_info->var.yres_virtual = msmfb->yres * 2;
> - fb_info->var.bits_per_pixel = BITS_PER_PIXEL;
> + fb_info->var.bits_per_pixel = 16;
> fb_info->var.accel_flags = 0;
>
> fb_info->var.yoffset = 0;
> @@ -497,28 +532,30 @@ static int setup_fbmem(struct msmfb_info *msmfb,
> struct platform_device *pdev)
> struct fb_info *fb = msmfb->fb;
> struct resource *resource;
> unsigned long size = msmfb->xres * msmfb->yres *
> - (BITS_PER_PIXEL >> 3) * 2;
> + BYTES_PER_PIXEL(msmfb) * 2;
> + unsigned long resource_size;
> unsigned char *fbram;
>
> /* board file might have attached a resource describing an fb */
> resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> if (!resource)
> return -EINVAL;
> + resource_size = resource->end - resource->start + 1;
>
> /* check the resource is large enough to fit the fb */
> - if (resource->end - resource->start < size) {
> - printk(KERN_ERR "allocated resource is too small for "
> + if (resource_size < size) {
> + printk(KERN_ERR "msmfb: allocated resource is too small for "
> "fb\n");
> return -ENOMEM;
> }
> fb->fix.smem_start = resource->start;
> - fb->fix.smem_len = resource->end - resource->start;
> - fbram = ioremap(resource->start,
> - resource->end - resource->start);
> + fb->fix.smem_len = resource_size;
> + fbram = ioremap(resource->start, resource_size);
> if (fbram == 0) {
> printk(KERN_ERR "msmfb: cannot allocate fbram!\n");
> return -ENOMEM;
> }
> +
> fb->screen_base = fbram;
> return 0;
> }
> --
> Sent by an employee of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
>
> --
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