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Diffstat (limited to 'target/linux/brcm2708/patches-3.14/0026-bcm2708_fb-DMA-acceleration-for-fb_copyarea.patch')
-rw-r--r--target/linux/brcm2708/patches-3.14/0026-bcm2708_fb-DMA-acceleration-for-fb_copyarea.patch460
1 files changed, 460 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-3.14/0026-bcm2708_fb-DMA-acceleration-for-fb_copyarea.patch b/target/linux/brcm2708/patches-3.14/0026-bcm2708_fb-DMA-acceleration-for-fb_copyarea.patch
new file mode 100644
index 0000000000..412ffd6485
--- /dev/null
+++ b/target/linux/brcm2708/patches-3.14/0026-bcm2708_fb-DMA-acceleration-for-fb_copyarea.patch
@@ -0,0 +1,460 @@
+From c2731f282848af32425043a2df88c1289538983e Mon Sep 17 00:00:00 2001
+From: Siarhei Siamashka <siarhei.siamashka@gmail.com>
+Date: Mon, 17 Jun 2013 16:00:25 +0300
+Subject: [PATCH 26/54] bcm2708_fb: DMA acceleration for fb_copyarea
+
+Based on http://www.raspberrypi.org/phpBB3/viewtopic.php?p=62425#p62425
+Also used Simon's dmaer_master module as a reference for tweaking DMA
+settings for better performance.
+
+For now busylooping only. IRQ support might be added later.
+With non-overclocked Raspberry Pi, the performance is ~360 MB/s
+for simple copy or ~260 MB/s for two-pass copy (used when dragging
+windows to the right).
+
+In the case of using DMA channel 0, the performance improves
+to ~440 MB/s.
+
+For comparison, VFP optimized CPU copy can only do ~114 MB/s in
+the same conditions (hindered by reading uncached source buffer).
+
+Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
+
+bcm2708_fb: report number of dma copies
+
+Add a counter (exported via debugfs) reporting the
+number of dma copies that the framebuffer driver
+has done, in order to help evaluate different
+optimization strategies.
+
+Signed-off-by: Luke Diamand <luked@broadcom.com>
+
+bcm2708_fb: use IRQ for DMA copies
+
+The copyarea ioctl() uses DMA to speed things along. This
+was busy-waiting for completion. This change supports using
+an interrupt instead for larger transfers. For small
+transfers, busy-waiting is still likely to be faster.
+
+Signed-off-by: Luke Diamand <luke@diamand.org>
+---
+ arch/arm/mach-bcm2708/dma.c | 8 +
+ arch/arm/mach-bcm2708/include/mach/dma.h | 2 +
+ drivers/video/bcm2708_fb.c | 273 ++++++++++++++++++++++++++++++-
+ 3 files changed, 278 insertions(+), 5 deletions(-)
+
+diff --git a/arch/arm/mach-bcm2708/dma.c b/arch/arm/mach-bcm2708/dma.c
+index 51d147a..1da2413 100644
+--- a/arch/arm/mach-bcm2708/dma.c
++++ b/arch/arm/mach-bcm2708/dma.c
+@@ -83,6 +83,14 @@ extern void bcm_dma_wait_idle(void __iomem *dma_chan_base)
+
+ EXPORT_SYMBOL_GPL(bcm_dma_start);
+
++extern bool bcm_dma_is_busy(void __iomem *dma_chan_base)
++{
++ dsb();
++
++ return readl(dma_chan_base + BCM2708_DMA_CS) & BCM2708_DMA_ACTIVE;
++}
++EXPORT_SYMBOL_GPL(bcm_dma_is_busy);
++
+ /* Complete an ongoing DMA (assuming its results are to be ignored)
+ Does nothing if there is no DMA in progress.
+ This routine waits for the current AXI transfer to complete before
+diff --git a/arch/arm/mach-bcm2708/include/mach/dma.h b/arch/arm/mach-bcm2708/include/mach/dma.h
+index ac7a4a0..6d2f9a0 100644
+--- a/arch/arm/mach-bcm2708/include/mach/dma.h
++++ b/arch/arm/mach-bcm2708/include/mach/dma.h
+@@ -62,11 +62,13 @@ struct bcm2708_dma_cb {
+ unsigned long next;
+ unsigned long pad[2];
+ };
++struct scatterlist;
+
+ extern int bcm_sg_suitable_for_dma(struct scatterlist *sg_ptr, int sg_len);
+ extern void bcm_dma_start(void __iomem *dma_chan_base,
+ dma_addr_t control_block);
+ extern void bcm_dma_wait_idle(void __iomem *dma_chan_base);
++extern bool bcm_dma_is_busy(void __iomem *dma_chan_base);
+ extern int /*rc*/ bcm_dma_abort(void __iomem *dma_chan_base);
+
+ /* When listing features we can ask for when allocating DMA channels give
+diff --git a/drivers/video/bcm2708_fb.c b/drivers/video/bcm2708_fb.c
+index 54cd760..798eb52 100644
+--- a/drivers/video/bcm2708_fb.c
++++ b/drivers/video/bcm2708_fb.c
+@@ -21,13 +21,16 @@
+ #include <linux/mm.h>
+ #include <linux/fb.h>
+ #include <linux/init.h>
++#include <linux/interrupt.h>
+ #include <linux/ioport.h>
+ #include <linux/list.h>
+ #include <linux/platform_device.h>
+ #include <linux/clk.h>
+ #include <linux/printk.h>
+ #include <linux/console.h>
++#include <linux/debugfs.h>
+
++#include <mach/dma.h>
+ #include <mach/platform.h>
+ #include <mach/vcio.h>
+
+@@ -51,6 +54,10 @@ static int fbheight = 480; /* module parameter */
+ static int fbdepth = 16; /* module parameter */
+ static int fbswap = 0; /* module parameter */
+
++static u32 dma_busy_wait_threshold = 1<<15;
++module_param(dma_busy_wait_threshold, int, 0644);
++MODULE_PARM_DESC(dma_busy_wait_threshold, "Busy-wait for DMA completion below this area");
++
+ /* this data structure describes each frame buffer device we find */
+
+ struct fbinfo_s {
+@@ -62,16 +69,73 @@ struct fbinfo_s {
+ u16 cmap[256];
+ };
+
++struct bcm2708_fb_stats {
++ struct debugfs_regset32 regset;
++ u32 dma_copies;
++ u32 dma_irqs;
++};
++
+ struct bcm2708_fb {
+ struct fb_info fb;
+ struct platform_device *dev;
+ struct fbinfo_s *info;
+ dma_addr_t dma;
+ u32 cmap[16];
++ int dma_chan;
++ int dma_irq;
++ void __iomem *dma_chan_base;
++ void *cb_base; /* DMA control blocks */
++ dma_addr_t cb_handle;
++ struct dentry *debugfs_dir;
++ wait_queue_head_t dma_waitq;
++ struct bcm2708_fb_stats stats;
+ };
+
+ #define to_bcm2708(info) container_of(info, struct bcm2708_fb, fb)
+
++static void bcm2708_fb_debugfs_deinit(struct bcm2708_fb *fb)
++{
++ debugfs_remove_recursive(fb->debugfs_dir);
++ fb->debugfs_dir = NULL;
++}
++
++static int bcm2708_fb_debugfs_init(struct bcm2708_fb *fb)
++{
++ static struct debugfs_reg32 stats_registers[] = {
++ {
++ "dma_copies",
++ offsetof(struct bcm2708_fb_stats, dma_copies)
++ },
++ {
++ "dma_irqs",
++ offsetof(struct bcm2708_fb_stats, dma_irqs)
++ },
++ };
++
++ fb->debugfs_dir = debugfs_create_dir(DRIVER_NAME, NULL);
++ if (!fb->debugfs_dir) {
++ pr_warn("%s: could not create debugfs entry\n",
++ __func__);
++ return -EFAULT;
++ }
++
++ fb->stats.regset.regs = stats_registers;
++ fb->stats.regset.nregs = ARRAY_SIZE(stats_registers);
++ fb->stats.regset.base = &fb->stats;
++
++ if (!debugfs_create_regset32(
++ "stats", 0444, fb->debugfs_dir, &fb->stats.regset)) {
++ pr_warn("%s: could not create statistics registers\n",
++ __func__);
++ goto fail;
++ }
++ return 0;
++
++fail:
++ bcm2708_fb_debugfs_deinit(fb);
++ return -EFAULT;
++}
++
+ static int bcm2708_fb_set_bitfields(struct fb_var_screeninfo *var)
+ {
+ int ret = 0;
+@@ -322,11 +386,148 @@ static void bcm2708_fb_fillrect(struct fb_info *info,
+ cfb_fillrect(info, rect);
+ }
+
++/* A helper function for configuring dma control block */
++static void set_dma_cb(struct bcm2708_dma_cb *cb,
++ int burst_size,
++ dma_addr_t dst,
++ int dst_stride,
++ dma_addr_t src,
++ int src_stride,
++ int w,
++ int h)
++{
++ cb->info = BCM2708_DMA_BURST(burst_size) | BCM2708_DMA_S_WIDTH |
++ BCM2708_DMA_S_INC | BCM2708_DMA_D_WIDTH |
++ BCM2708_DMA_D_INC | BCM2708_DMA_TDMODE;
++ cb->dst = dst;
++ cb->src = src;
++ /*
++ * This is not really obvious from the DMA documentation,
++ * but the top 16 bits must be programmmed to "height -1"
++ * and not "height" in 2D mode.
++ */
++ cb->length = ((h - 1) << 16) | w;
++ cb->stride = ((dst_stride - w) << 16) | (u16)(src_stride - w);
++ cb->pad[0] = 0;
++ cb->pad[1] = 0;
++}
++
+ static void bcm2708_fb_copyarea(struct fb_info *info,
+ const struct fb_copyarea *region)
+ {
+- /*print_debug("bcm2708_fb_copyarea\n"); */
+- cfb_copyarea(info, region);
++ struct bcm2708_fb *fb = to_bcm2708(info);
++ struct bcm2708_dma_cb *cb = fb->cb_base;
++ int bytes_per_pixel = (info->var.bits_per_pixel + 7) >> 3;
++ /* Channel 0 supports larger bursts and is a bit faster */
++ int burst_size = (fb->dma_chan == 0) ? 8 : 2;
++ int pixels = region->width * region->height;
++
++ /* Fallback to cfb_copyarea() if we don't like something */
++ if (bytes_per_pixel > 4 ||
++ info->var.xres * info->var.yres > 1920 * 1200 ||
++ region->width <= 0 || region->width > info->var.xres ||
++ region->height <= 0 || region->height > info->var.yres ||
++ region->sx < 0 || region->sx >= info->var.xres ||
++ region->sy < 0 || region->sy >= info->var.yres ||
++ region->dx < 0 || region->dx >= info->var.xres ||
++ region->dy < 0 || region->dy >= info->var.yres ||
++ region->sx + region->width > info->var.xres ||
++ region->dx + region->width > info->var.xres ||
++ region->sy + region->height > info->var.yres ||
++ region->dy + region->height > info->var.yres) {
++ cfb_copyarea(info, region);
++ return;
++ }
++
++ if (region->dy == region->sy && region->dx > region->sx) {
++ /*
++ * A difficult case of overlapped copy. Because DMA can't
++ * copy individual scanlines in backwards direction, we need
++ * two-pass processing. We do it by programming a chain of dma
++ * control blocks in the first 16K part of the buffer and use
++ * the remaining 48K as the intermediate temporary scratch
++ * buffer. The buffer size is sufficient to handle up to
++ * 1920x1200 resolution at 32bpp pixel depth.
++ */
++ int y;
++ dma_addr_t control_block_pa = fb->cb_handle;
++ dma_addr_t scratchbuf = fb->cb_handle + 16 * 1024;
++ int scanline_size = bytes_per_pixel * region->width;
++ int scanlines_per_cb = (64 * 1024 - 16 * 1024) / scanline_size;
++
++ for (y = 0; y < region->height; y += scanlines_per_cb) {
++ dma_addr_t src =
++ fb->fb.fix.smem_start +
++ bytes_per_pixel * region->sx +
++ (region->sy + y) * fb->fb.fix.line_length;
++ dma_addr_t dst =
++ fb->fb.fix.smem_start +
++ bytes_per_pixel * region->dx +
++ (region->dy + y) * fb->fb.fix.line_length;
++
++ if (region->height - y < scanlines_per_cb)
++ scanlines_per_cb = region->height - y;
++
++ set_dma_cb(cb, burst_size, scratchbuf, scanline_size,
++ src, fb->fb.fix.line_length,
++ scanline_size, scanlines_per_cb);
++ control_block_pa += sizeof(struct bcm2708_dma_cb);
++ cb->next = control_block_pa;
++ cb++;
++
++ set_dma_cb(cb, burst_size, dst, fb->fb.fix.line_length,
++ scratchbuf, scanline_size,
++ scanline_size, scanlines_per_cb);
++ control_block_pa += sizeof(struct bcm2708_dma_cb);
++ cb->next = control_block_pa;
++ cb++;
++ }
++ /* move the pointer back to the last dma control block */
++ cb--;
++ } else {
++ /* A single dma control block is enough. */
++ int sy, dy, stride;
++ if (region->dy <= region->sy) {
++ /* processing from top to bottom */
++ dy = region->dy;
++ sy = region->sy;
++ stride = fb->fb.fix.line_length;
++ } else {
++ /* processing from bottom to top */
++ dy = region->dy + region->height - 1;
++ sy = region->sy + region->height - 1;
++ stride = -fb->fb.fix.line_length;
++ }
++ set_dma_cb(cb, burst_size,
++ fb->fb.fix.smem_start + dy * fb->fb.fix.line_length +
++ bytes_per_pixel * region->dx,
++ stride,
++ fb->fb.fix.smem_start + sy * fb->fb.fix.line_length +
++ bytes_per_pixel * region->sx,
++ stride,
++ region->width * bytes_per_pixel,
++ region->height);
++ }
++
++ /* end of dma control blocks chain */
++ cb->next = 0;
++
++
++ if (pixels < dma_busy_wait_threshold) {
++ bcm_dma_start(fb->dma_chan_base, fb->cb_handle);
++ bcm_dma_wait_idle(fb->dma_chan_base);
++ } else {
++ void __iomem *dma_chan = fb->dma_chan_base;
++ cb->info |= BCM2708_DMA_INT_EN;
++ bcm_dma_start(fb->dma_chan_base, fb->cb_handle);
++ while (bcm_dma_is_busy(dma_chan)) {
++ wait_event_interruptible(
++ fb->dma_waitq,
++ !bcm_dma_is_busy(dma_chan));
++ }
++ fb->stats.dma_irqs++;
++ }
++ fb->stats.dma_copies++;
+ }
+
+ static void bcm2708_fb_imageblit(struct fb_info *info,
+@@ -336,6 +537,24 @@ static void bcm2708_fb_imageblit(struct fb_info *info,
+ cfb_imageblit(info, image);
+ }
+
++static irqreturn_t bcm2708_fb_dma_irq(int irq, void *cxt)
++{
++ struct bcm2708_fb *fb = cxt;
++
++ /* FIXME: should read status register to check if this is
++ * actually interrupting us or not, in case this interrupt
++ * ever becomes shared amongst several DMA channels
++ *
++ * readl(dma_chan_base + BCM2708_DMA_CS) & BCM2708_DMA_IRQ;
++ */
++
++ /* acknowledge the interrupt */
++ writel(BCM2708_DMA_INT, fb->dma_chan_base + BCM2708_DMA_CS);
++
++ wake_up(&fb->dma_waitq);
++ return IRQ_HANDLED;
++}
++
+ static struct fb_ops bcm2708_fb_ops = {
+ .owner = THIS_MODULE,
+ .fb_check_var = bcm2708_fb_check_var,
+@@ -365,7 +584,7 @@ static int bcm2708_fb_register(struct bcm2708_fb *fb)
+ fb->dma = dma;
+ }
+ fb->fb.fbops = &bcm2708_fb_ops;
+- fb->fb.flags = FBINFO_FLAG_DEFAULT;
++ fb->fb.flags = FBINFO_FLAG_DEFAULT | FBINFO_HWACCEL_COPYAREA;
+ fb->fb.pseudo_palette = fb->cmap;
+
+ strncpy(fb->fb.fix.id, bcm2708_name, sizeof(fb->fb.fix.id));
+@@ -396,6 +615,7 @@ static int bcm2708_fb_register(struct bcm2708_fb *fb)
+ fb->fb.monspecs.dclkmax = 100000000;
+
+ bcm2708_fb_set_bitfields(&fb->fb.var);
++ init_waitqueue_head(&fb->dma_waitq);
+
+ /*
+ * Allocate colourmap.
+@@ -421,14 +641,45 @@ static int bcm2708_fb_probe(struct platform_device *dev)
+ struct bcm2708_fb *fb;
+ int ret;
+
+- fb = kmalloc(sizeof(struct bcm2708_fb), GFP_KERNEL);
++ fb = kzalloc(sizeof(struct bcm2708_fb), GFP_KERNEL);
+ if (!fb) {
+ dev_err(&dev->dev,
+ "could not allocate new bcm2708_fb struct\n");
+ ret = -ENOMEM;
+ goto free_region;
+ }
+- memset(fb, 0, sizeof(struct bcm2708_fb));
++
++ bcm2708_fb_debugfs_init(fb);
++
++ fb->cb_base = dma_alloc_writecombine(&dev->dev, SZ_64K,
++ &fb->cb_handle, GFP_KERNEL);
++ if (!fb->cb_base) {
++ dev_err(&dev->dev, "cannot allocate DMA CBs\n");
++ ret = -ENOMEM;
++ goto free_fb;
++ }
++
++ pr_info("BCM2708FB: allocated DMA memory %08x\n",
++ fb->cb_handle);
++
++ ret = bcm_dma_chan_alloc(BCM_DMA_FEATURE_BULK,
++ &fb->dma_chan_base, &fb->dma_irq);
++ if (ret < 0) {
++ dev_err(&dev->dev, "couldn't allocate a DMA channel\n");
++ goto free_cb;
++ }
++ fb->dma_chan = ret;
++
++ ret = request_irq(fb->dma_irq, bcm2708_fb_dma_irq,
++ 0, "bcm2708_fb dma", fb);
++ if (ret) {
++ pr_err("%s: failed to request DMA irq\n", __func__);
++ goto free_dma_chan;
++ }
++
++
++ pr_info("BCM2708FB: allocated DMA channel %d @ %p\n",
++ fb->dma_chan, fb->dma_chan_base);
+
+ fb->dev = dev;
+
+@@ -438,6 +689,11 @@ static int bcm2708_fb_probe(struct platform_device *dev)
+ goto out;
+ }
+
++free_dma_chan:
++ bcm_dma_chan_free(fb->dma_chan);
++free_cb:
++ dma_free_writecombine(&dev->dev, SZ_64K, fb->cb_base, fb->cb_handle);
++free_fb:
+ kfree(fb);
+ free_region:
+ dev_err(&dev->dev, "probe failed, err %d\n", ret);
+@@ -455,8 +711,15 @@ static int bcm2708_fb_remove(struct platform_device *dev)
+ iounmap(fb->fb.screen_base);
+ unregister_framebuffer(&fb->fb);
+
++ dma_free_writecombine(&dev->dev, SZ_64K, fb->cb_base, fb->cb_handle);
++ bcm_dma_chan_free(fb->dma_chan);
++
+ dma_free_coherent(NULL, PAGE_ALIGN(sizeof(*fb->info)), (void *)fb->info,
+ fb->dma);
++ bcm2708_fb_debugfs_deinit(fb);
++
++ free_irq(fb->dma_irq, fb);
++
+ kfree(fb);
+
+ return 0;
+--
+1.9.1
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-15 20:50:51 +0000