sh: LCDC dcache flush for deferred io

Since writenotify on uncached vmas is unsupported in 2.6.31,
live with cached framebuffer memory in the deferred io
case for now and flush the dcache before forcing refresh.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Magnus damm <damm@igel.co.jp>

drivers/video/sh_mobile_lcdcfb.c

@@ -17,6 +17,7 @@
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
+#include <linux/vmalloc.h>
 #include <video/sh_mobile_lcdc.h>
 #include <asm/atomic.h>
 
@@ -33,6 +34,7 @@ struct sh_mobile_lcdc_chan {
 	struct fb_info info;
 	dma_addr_t dma_handle;
 	struct fb_deferred_io defio;
+	struct scatterlist *sglist;
 	unsigned long frame_end;
 	wait_queue_head_t frame_end_wait;
 };
@@ -206,16 +208,38 @@ static void sh_mobile_lcdc_clk_on(struct sh_mobile_lcdc_priv *priv) {}
 static void sh_mobile_lcdc_clk_off(struct sh_mobile_lcdc_priv *priv) {}
 #endif
 
+static int sh_mobile_lcdc_sginit(struct fb_info *info,
+				  struct list_head *pagelist)
+{
+	struct sh_mobile_lcdc_chan *ch = info->par;
+	unsigned int nr_pages_max = info->fix.smem_len >> PAGE_SHIFT;
+	struct page *page;
+	int nr_pages = 0;
+
+	sg_init_table(ch->sglist, nr_pages_max);
+
+	list_for_each_entry(page, pagelist, lru)
+		sg_set_page(&ch->sglist[nr_pages++], page, PAGE_SIZE, 0);
+
+	return nr_pages;
+}
+
 static void sh_mobile_lcdc_deferred_io(struct fb_info *info,
 				       struct list_head *pagelist)
 {
 	struct sh_mobile_lcdc_chan *ch = info->par;
+	unsigned int nr_pages;
 
 	/* enable clocks before accessing hardware */
 	sh_mobile_lcdc_clk_on(ch->lcdc);
 
+	nr_pages = sh_mobile_lcdc_sginit(info, pagelist);
+	dma_map_sg(info->dev, ch->sglist, nr_pages, DMA_TO_DEVICE);
+
 	/* trigger panel update */
 	lcdc_write_chan(ch, LDSM2R, 1);
+
+	dma_unmap_sg(info->dev, ch->sglist, nr_pages, DMA_TO_DEVICE);
 }
 
 static void sh_mobile_lcdc_deferred_io_touch(struct fb_info *info)
@@ -846,21 +870,31 @@ static int __init sh_mobile_lcdc_probe(struct platform_device *pdev)
 	}
 
 	for (i = 0; i < j; i++) {
-		error = register_framebuffer(&priv->ch[i].info);
-		if (error < 0)
+		struct sh_mobile_lcdc_chan *ch = priv->ch + i;
+
+		info = &ch->info;
+
+		if (info->fbdefio) {
+			priv->ch->sglist = vmalloc(sizeof(struct scatterlist) *
+					info->fix.smem_len >> PAGE_SHIFT);
+			if (!priv->ch->sglist) {
+				dev_err(&pdev->dev, "cannot allocate sglist\n");
 				goto err1;
 			}
+		}
+
+		error = register_framebuffer(info);
+		if (error < 0)
+			goto err1;
 
-	for (i = 0; i < j; i++) {
-		info = &priv->ch[i].info;
 		dev_info(info->dev,
 			 "registered %s/%s as %dx%d %dbpp.\n",
 			 pdev->name,
-			 (priv->ch[i].cfg.chan == LCDC_CHAN_MAINLCD) ?
+			 (ch->cfg.chan == LCDC_CHAN_MAINLCD) ?
 			 "mainlcd" : "sublcd",
-			 (int) priv->ch[i].cfg.lcd_cfg.xres,
-			 (int) priv->ch[i].cfg.lcd_cfg.yres,
-			 priv->ch[i].cfg.bpp);
+			 (int) ch->cfg.lcd_cfg.xres,
+			 (int) ch->cfg.lcd_cfg.yres,
+			 ch->cfg.bpp);
 
 		/* deferred io mode: disable clock to save power */
 		if (info->fbdefio)
@@ -892,6 +926,9 @@ static int sh_mobile_lcdc_remove(struct platform_device *pdev)
 		if (!info->device)
 			continue;
 
+		if (priv->ch[i].sglist)
+			vfree(priv->ch[i].sglist);
+
 		dma_free_coherent(&pdev->dev, info->fix.smem_len,
 				  info->screen_base, priv->ch[i].dma_handle);
 		fb_dealloc_cmap(&info->cmap);