ENGR00151639 - EPDC fb: Memory for PxP workaround buffers may be reduced

- This patch changes the way that buffers are allocated and used for the
case where PxP alignment limitations are not met (a copy from the
update source buffer into a temporary buffer before initiating the
PxP processing task is required).  Previously, a buffer was allocated
on a per-update basis, resulting in a large number of copy buffers.  Now,
we allocate just one copy buffer that can be reused any time the PxP
alignment workaround is required.  This is okay because it is assured
that only one PxP transaction can be prepared at a time.

Signed-off-by: Danny Nold <dannynold@freescale.com>

1 files changed, 44 insertions, 39 deletions

diff --git a/drivers/video/mxc/mxc_epdc_fb.c b/drivers/video/mxc/mxc_epdc_fb.c
index 39e442d9c8b3..a28e57092698 100644
--- a/drivers/video/mxc/mxc_epdc_fb.c
+++ b/drivers/video/mxc/mxc_epdc_fb.c
@@ -102,9 +102,6 @@ struct update_data_list {
 	struct list_head list;
 	dma_addr_t phys_addr;		/* Pointer to phys address of processed Y buf */
 	void *virt_addr;
-	u32 size;
-	dma_addr_t phys_addr_copybuf;	/* Phys address of copied update data */
-	void *virt_addr_copybuf;	/* Used for PxP SW workaround */
 	struct update_desc_list *update_desc;
 	int lut_num;			/* Assigned before update is processed into working buffer */
 	int collision_mask;		/* Set when update results in collision */
@@ -121,6 +118,7 @@ struct mxc_epdc_fb_data {
 	struct imx_epdc_fb_mode *cur_mode;
 	struct imx_epdc_fb_platform_data *pdata;
 	int blank;
+	u32 max_pix_size;
 	ssize_t map_size;
 	dma_addr_t phys_start;
 	u32 fb_offset;
@@ -161,6 +159,8 @@ struct mxc_epdc_fb_data {
 	u32 *working_buffer_virt;
 	u32 working_buffer_phys;
 	u32 working_buffer_size;
+	dma_addr_t phys_addr_copybuf;	/* Phys address of copied update data */
+	void *virt_addr_copybuf;	/* Used for PxP SW workaround */
 	u32 order_cnt;
 	struct list_head full_marker_list;
 	u32 lut_update_order[EPDC_NUM_LUTS];
@@ -1529,7 +1529,7 @@ static void copy_before_process(struct mxc_epdc_fb_data *fb_data,
 	struct mxcfb_update_data *upd_data =
 		&upd_data_list->update_desc->upd_data;
 	int i;
-	unsigned char *temp_buf_ptr = upd_data_list->virt_addr_copybuf;
+	unsigned char *temp_buf_ptr = fb_data->virt_addr_copybuf;
 	unsigned char *src_ptr;
 	struct mxcfb_rect *src_upd_region;
 	int temp_buf_stride;
@@ -1667,6 +1667,10 @@ static int epdc_process_update(struct update_data_list *upd_data_list,
 			ALIGN(src_upd_region->width + pix_per_line_added, 8)))
 		line_overflow = true;
 
+	/* Grab pxp_mutex here so that we protect access
+	 * to copybuf in addition to the PxP structures */
+	mutex_lock(&fb_data->pxp_mutex);
+
 	if (((width_unaligned || height_unaligned || input_unaligned) &&
 		(upd_desc_list->upd_data.waveform_mode == WAVEFORM_MODE_AUTO))
 		|| line_overflow) {
@@ -1757,13 +1761,11 @@ static int epdc_process_update(struct update_data_list *upd_data_list,
 
 	upd_desc_list->epdc_offs = ALIGN(pxp_output_offs, 8);
 
-	mutex_lock(&fb_data->pxp_mutex);
-
 	/* Source address either comes from alternate buffer
 	   provided in update data, or from the framebuffer. */
 	if (use_temp_buf)
 		sg_dma_address(&fb_data->sg[0]) =
-			upd_data_list->phys_addr_copybuf;
+			fb_data->phys_addr_copybuf;
 	else if (upd_desc_list->upd_data.flags & EPDC_FLAG_USE_ALT_BUFFER)
 		sg_dma_address(&fb_data->sg[0]) =
 			upd_desc_list->upd_data.alt_buffer_data.phys_addr
@@ -1782,7 +1784,7 @@ static int epdc_process_update(struct update_data_list *upd_data_list,
 	sg_dma_address(&fb_data->sg[1]) = upd_data_list->phys_addr
 						+ pxp_output_shift;
 	sg_set_page(&fb_data->sg[1], virt_to_page(upd_data_list->virt_addr),
-		    upd_data_list->size,
+		    fb_data->max_pix_size,
 		    offset_in_page(upd_data_list->virt_addr));
 
 	/*
@@ -3463,7 +3465,7 @@ int __devinit mxc_epdc_fb_probe(struct platform_device *pdev)
 	char *panel_str = NULL;
 	char name[] = "mxcepdcfb";
 	struct fb_videomode *vmode;
-	int xres_virt, yres_virt, max_pix_size, buf_size;
+	int xres_virt, yres_virt, buf_size;
 	int xres_virt_rot, yres_virt_rot, pix_size_rot;
 	struct fb_var_screeninfo *var_info;
 	struct fb_fix_screeninfo *fix_info;
@@ -3555,7 +3557,7 @@ int __devinit mxc_epdc_fb_probe(struct platform_device *pdev)
 	 */
 	xres_virt = ALIGN(vmode->xres, 32);
 	yres_virt = ALIGN(vmode->yres, 128);
-	max_pix_size = PAGE_ALIGN(xres_virt * yres_virt);
+	fb_data->max_pix_size = PAGE_ALIGN(xres_virt * yres_virt);
 
 	/*
 	 * Have to check to see if aligned buffer size when rotated
@@ -3564,10 +3566,10 @@ int __devinit mxc_epdc_fb_probe(struct platform_device *pdev)
 	xres_virt_rot = ALIGN(vmode->yres, 32);
 	yres_virt_rot = ALIGN(vmode->xres, 128);
 	pix_size_rot = PAGE_ALIGN(xres_virt_rot * yres_virt_rot);
-	max_pix_size = (max_pix_size > pix_size_rot) ?
-				max_pix_size : pix_size_rot;
+	fb_data->max_pix_size = (fb_data->max_pix_size > pix_size_rot) ?
+				fb_data->max_pix_size : pix_size_rot;
 
-	buf_size = max_pix_size * fb_data->default_bpp/8;
+	buf_size = fb_data->max_pix_size * fb_data->default_bpp/8;
 
 	/* Compute the number of screens needed based on X memory requested */
 	if (x_mem_size > 0) {
@@ -3721,14 +3723,12 @@ int __devinit mxc_epdc_fb_probe(struct platform_device *pdev)
 		}
 
 		/*
+		 * Allocate memory for PxP output buffer.
 		 * Each update buffer is 1 byte per pixel, and can
 		 * be as big as the full-screen frame buffer
 		 */
-		upd_list->size = max_pix_size;
-
-		/* Allocate memory for PxP output buffer */
 		upd_list->virt_addr =
-		    dma_alloc_coherent(fb_data->info.device, upd_list->size,
+		    dma_alloc_coherent(fb_data->info.device, fb_data->max_pix_size,
 				       &upd_list->phys_addr, GFP_DMA);
 		if (upd_list->virt_addr == NULL) {
 			kfree(upd_list);
@@ -3740,17 +3740,20 @@ int __devinit mxc_epdc_fb_probe(struct platform_device *pdev)
 		list_add(&upd_list->list, &fb_data->upd_buf_free_list);
 
 		dev_dbg(fb_data->info.device, "allocated %d bytes @ 0x%08X\n",
-			upd_list->size, upd_list->phys_addr);
-
-		/* Allocate memory for PxP SW workaround buffers */
-		/* These buffers are used to hold copy of the update region */
-		upd_list->virt_addr_copybuf =
-		    dma_alloc_coherent(fb_data->info.device, upd_list->size*2,
-				       &upd_list->phys_addr_copybuf, GFP_DMA);
-		if (upd_list->virt_addr_copybuf == NULL) {
-			ret = -ENOMEM;
-			goto out_upd_buffers;
-		}
+			fb_data->max_pix_size, upd_list->phys_addr);
+	}
+
+	/*
+	 * Allocate memory for PxP SW workaround buffer
+	 * These buffers are used to hold copy of the update region,
+	 * before sending it to PxP for processing.
+	 */
+	fb_data->virt_addr_copybuf =
+	    dma_alloc_coherent(fb_data->info.device, fb_data->max_pix_size*2,
+			       &fb_data->phys_addr_copybuf, GFP_DMA);
+	if (fb_data->virt_addr_copybuf == NULL) {
+		ret = -ENOMEM;
+		goto out_upd_buffers;
 	}
 
 	fb_data->working_buffer_size = vmode->yres * vmode->xres * 2;
@@ -3761,7 +3764,7 @@ int __devinit mxc_epdc_fb_probe(struct platform_device *pdev)
 	if (fb_data->working_buffer_virt == NULL) {
 		dev_err(&pdev->dev, "Can't allocate mem for working buf!\n");
 		ret = -ENOMEM;
-		goto out_upd_buffers;
+		goto out_copybuffer;
 	}
 
 	/* Initialize EPDC pins */
@@ -3773,14 +3776,14 @@ int __devinit mxc_epdc_fb_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "Unable to get EPDC AXI clk."
 			"err = 0x%x\n", (int)fb_data->epdc_clk_axi);
 		ret = -ENODEV;
-		goto out_upd_buffers;
+		goto out_copybuffer;
 	}
 	fb_data->epdc_clk_pix = clk_get(fb_data->dev, "epdc_pix");
 	if (IS_ERR(fb_data->epdc_clk_pix)) {
 		dev_err(&pdev->dev, "Unable to get EPDC pix clk."
 			"err = 0x%x\n", (int)fb_data->epdc_clk_pix);
 		ret = -ENODEV;
-		goto out_upd_buffers;
+		goto out_copybuffer;
 	}
 
 	fb_data->in_init = false;
@@ -4004,16 +4007,17 @@ out_dma_work_buf:
 		fb_data->working_buffer_virt, fb_data->working_buffer_phys);
 	if (fb_data->pdata->put_pins)
 		fb_data->pdata->put_pins();
+out_copybuffer:
+	dma_free_writecombine(&pdev->dev, fb_data->max_pix_size*2,
+			      fb_data->virt_addr_copybuf,
+			      fb_data->phys_addr_copybuf);
 out_upd_buffers:
 	list_for_each_entry_safe(plist, temp_list, &fb_data->upd_buf_free_list,
 			list) {
 		list_del(&plist->list);
-		dma_free_writecombine(&pdev->dev, plist->size,
+		dma_free_writecombine(&pdev->dev, fb_data->max_pix_size,
 				      plist->virt_addr,
 				      plist->phys_addr);
-		dma_free_writecombine(&pdev->dev, plist->size*2,
-				      plist->virt_addr_copybuf,
-				      plist->phys_addr_copybuf);
 		kfree(plist);
 	}
 out_dma_fb:
@@ -4053,15 +4057,16 @@ static int mxc_epdc_fb_remove(struct platform_device *pdev)
 		dma_free_writecombine(&pdev->dev, fb_data->waveform_buffer_size,
 				fb_data->waveform_buffer_virt,
 				fb_data->waveform_buffer_phys);
+	if (fb_data->virt_addr_copybuf != NULL)
+		dma_free_writecombine(&pdev->dev, fb_data->max_pix_size*2,
+				fb_data->virt_addr_copybuf,
+				fb_data->phys_addr_copybuf);
 	list_for_each_entry_safe(plist, temp_list, &fb_data->upd_buf_free_list,
 			list) {
 		list_del(&plist->list);
-		dma_free_writecombine(&pdev->dev, plist->size,
+		dma_free_writecombine(&pdev->dev, fb_data->max_pix_size,
 				      plist->virt_addr,
 				      plist->phys_addr);
-		dma_free_writecombine(&pdev->dev, plist->size*2,
-				      plist->virt_addr_copybuf,
-				      plist->phys_addr_copybuf);
 		kfree(plist);
 	}
 #ifdef CONFIG_FB_MXC_EINK_AUTO_UPDATE_MODE