dab5a44067
n As usual these patches were extracted and rebased from the raspberry pi repo: https://github.com/raspberrypi/linux/tree/rpi-4.4.y Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
167 lines
4.8 KiB
Diff
167 lines
4.8 KiB
Diff
From c6175951b8f95d9f2c30d00ec069cafd23c6f376 Mon Sep 17 00:00:00 2001
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From: popcornmix <popcornmix@gmail.com>
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Date: Sat, 5 Nov 2016 14:14:43 +0000
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Subject: [PATCH] bcm2708_fb: Add ioctl for reading gpu memory through dma
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---
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drivers/video/fbdev/bcm2708_fb.c | 109 +++++++++++++++++++++++++++++++++++++++
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include/uapi/linux/fb.h | 7 +++
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2 files changed, 116 insertions(+)
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--- a/drivers/video/fbdev/bcm2708_fb.c
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+++ b/drivers/video/fbdev/bcm2708_fb.c
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@@ -31,8 +31,10 @@
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#include <linux/console.h>
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#include <linux/debugfs.h>
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#include <asm/sizes.h>
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+#include <asm/uaccess.h>
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#include <linux/io.h>
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#include <linux/dma-mapping.h>
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+#include <linux/cred.h>
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#include <soc/bcm2835/raspberrypi-firmware.h>
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//#define BCM2708_FB_DEBUG
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@@ -429,6 +431,110 @@ static int bcm2708_fb_pan_display(struct
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return result;
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}
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+static void dma_memcpy(struct bcm2708_fb *fb, dma_addr_t dst, dma_addr_t src, int size)
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+{
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+ int burst_size = (fb->dma_chan == 0) ? 8 : 2;
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+ struct bcm2708_dma_cb *cb = fb->cb_base;
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+
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+ cb->info = BCM2708_DMA_BURST(burst_size) | BCM2708_DMA_S_WIDTH |
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+ BCM2708_DMA_S_INC | BCM2708_DMA_D_WIDTH |
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+ BCM2708_DMA_D_INC | BCM2708_DMA_TDMODE;
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+ cb->dst = dst;
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+ cb->src = src;
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+ cb->length = size;
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+ cb->stride = 0;
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+ cb->pad[0] = 0;
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+ cb->pad[1] = 0;
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+ cb->next = 0;
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+
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+ if (size < dma_busy_wait_threshold) {
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+ bcm_dma_start(fb->dma_chan_base, fb->cb_handle);
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+ bcm_dma_wait_idle(fb->dma_chan_base);
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+ } else {
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+ void __iomem *dma_chan = fb->dma_chan_base;
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+ cb->info |= BCM2708_DMA_INT_EN;
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+ bcm_dma_start(fb->dma_chan_base, fb->cb_handle);
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+ while (bcm_dma_is_busy(dma_chan)) {
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+ wait_event_interruptible(
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+ fb->dma_waitq,
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+ !bcm_dma_is_busy(dma_chan));
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+ }
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+ fb->stats.dma_irqs++;
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+ }
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+ fb->stats.dma_copies++;
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+}
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+
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+#define INTALIAS_NORMAL(x) ((x)&~0xc0000000) // address with no aliases
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+#define INTALIAS_L1L2_NONALLOCATING(x) (((x)&~0xc0000000)|0x80000000) // cache coherent but non-allocating in L1 and L2
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+
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+static long vc_mem_copy(struct bcm2708_fb *fb, unsigned long arg)
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+{
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+ struct fb_dmacopy ioparam;
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+ size_t size = PAGE_SIZE;
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+ u32 *buf = NULL;
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+ dma_addr_t bus_addr;
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+ long rc = 0;
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+ size_t offset;
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+ struct { u32 base, length; } gpu = {};
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+
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+ /* restrict this to root user */
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+ if (!uid_eq(current_euid(), GLOBAL_ROOT_UID))
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+ {
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+ rc = -EFAULT;
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+ goto out;
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+ }
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+
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+ /* Get the parameter data.
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+ */
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+ if (copy_from_user
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+ (&ioparam, (void *)arg, sizeof(ioparam)) != 0) {
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+ pr_err("[%s]: failed to copy-from-user\n",
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+ __func__);
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+ rc = -EFAULT;
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+ goto out;
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+ }
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+
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+ rc = rpi_firmware_property(fb->fw,
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+ RPI_FIRMWARE_GET_VC_MEMORY,
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+ &gpu, sizeof(gpu));
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+ if (rc != 0 || gpu.base == 0 || gpu.length == 0) {
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+ pr_err("[%s]: Unable to determine gpu memory %ld,%x,%x)\n", __func__, rc, gpu.base, gpu.length);
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+ return -EFAULT;
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+ }
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+
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+ if (INTALIAS_NORMAL(ioparam.src) < gpu.base || INTALIAS_NORMAL(ioparam.src) >= gpu.base + gpu.length) {
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+ pr_err("[%s]: Invalid memory access %x (%x-%x)", __func__, INTALIAS_NORMAL(ioparam.src), gpu.base, gpu.base + gpu.length);
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+ return -EFAULT;
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+ }
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+
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+ buf = dma_alloc_coherent(NULL, PAGE_ALIGN(size), &bus_addr,
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+ GFP_ATOMIC);
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+ if (!buf) {
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+ pr_err("[%s]: failed to dma_alloc_coherent(%d)\n",
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+ __func__, size);
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+ rc = -ENOMEM;
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+ goto out;
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+ }
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+
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+ for (offset = 0; offset < ioparam.length; offset += size) {
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+ size_t remaining = ioparam.length - offset;
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+ size_t s = min(size, remaining);
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+ unsigned char *p = (unsigned char *)ioparam.src + offset;
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+ unsigned char *q = (unsigned char *)ioparam.dst + offset;
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+ dma_memcpy(fb, (dma_addr_t)buf, INTALIAS_L1L2_NONALLOCATING((dma_addr_t)p), size);
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+ if (copy_to_user(q, buf, s) != 0) {
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+ pr_err("[%s]: failed to copy-to-user\n",
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+ __func__);
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+ rc = -EFAULT;
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+ goto out;
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+ }
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+ }
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+out:
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+ if (buf)
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+ dma_free_coherent(NULL, PAGE_ALIGN(size), buf, bus_addr);
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+ return rc;
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+}
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+
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static int bcm2708_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
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{
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struct bcm2708_fb *fb = to_bcm2708(info);
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@@ -441,6 +547,9 @@ static int bcm2708_ioctl(struct fb_info
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RPI_FIRMWARE_FRAMEBUFFER_SET_VSYNC,
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&dummy, sizeof(dummy));
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break;
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+ case FBIODMACOPY:
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+ ret = vc_mem_copy(fb, arg);
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+ break;
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default:
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dev_dbg(info->device, "Unknown ioctl 0x%x\n", cmd);
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return -ENOTTY;
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--- a/include/uapi/linux/fb.h
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+++ b/include/uapi/linux/fb.h
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@@ -39,6 +39,7 @@
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* be concurrently added to the mainline kernel
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*/
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#define FBIOCOPYAREA _IOW('z', 0x21, struct fb_copyarea)
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+#define FBIODMACOPY _IOW('z', 0x22, struct fb_dmacopy)
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#define FB_TYPE_PACKED_PIXELS 0 /* Packed Pixels */
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#define FB_TYPE_PLANES 1 /* Non interleaved planes */
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@@ -351,6 +352,12 @@ struct fb_copyarea {
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__u32 sy;
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};
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+struct fb_dmacopy {
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+ dma_addr_t dst;
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+ dma_addr_t src;
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+ __u32 length;
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+};
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+
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struct fb_fillrect {
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__u32 dx; /* screen-relative */
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__u32 dy;
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