brcm2708: organize kernel patches
[openwrt/openwrt.git] / target / linux / brcm2708 / patches-4.19 / 950-0583-Pulled-in-the-multi-frame-buffer-support-from-the-Pi.patch
diff --git a/target/linux/brcm2708/patches-4.19/950-0583-Pulled-in-the-multi-frame-buffer-support-from-the-Pi.patch b/target/linux/brcm2708/patches-4.19/950-0583-Pulled-in-the-multi-frame-buffer-support-from-the-Pi.patch
new file mode 100644 (file)
index 0000000..883d947
--- /dev/null
@@ -0,0 +1,925 @@
+From 3e33fb46eb8791ba39fe4781f278487bcc2c3356 Mon Sep 17 00:00:00 2001
+From: James Hughes <james.hughes@raspberrypi.org>
+Date: Thu, 14 Mar 2019 13:27:54 +0000
+Subject: [PATCH] Pulled in the multi frame buffer support from the Pi3
+ repo
+
+---
+ drivers/video/fbdev/bcm2708_fb.c           | 580 +++++++++++++++------
+ include/soc/bcm2835/raspberrypi-firmware.h |   4 +
+ 2 files changed, 432 insertions(+), 152 deletions(-)
+
+--- a/drivers/video/fbdev/bcm2708_fb.c
++++ b/drivers/video/fbdev/bcm2708_fb.c
+@@ -2,6 +2,7 @@
+  *  linux/drivers/video/bcm2708_fb.c
+  *
+  * Copyright (C) 2010 Broadcom
++ * Copyright (C) 2018 Raspberry Pi (Trading) Ltd
+  *
+  * This file is subject to the terms and conditions of the GNU General Public
+  * License.  See the file COPYING in the main directory of this archive
+@@ -13,6 +14,7 @@
+  * Copyright 1999-2001 Jeff Garzik <jgarzik@pobox.com>
+  *
+  */
++
+ #include <linux/module.h>
+ #include <linux/kernel.h>
+ #include <linux/errno.h>
+@@ -36,6 +38,7 @@
+ #include <linux/dma-mapping.h>
+ #include <linux/cred.h>
+ #include <soc/bcm2835/raspberrypi-firmware.h>
++#include <linux/mutex.h>
+ //#define BCM2708_FB_DEBUG
+ #define MODULE_NAME "bcm2708_fb"
+@@ -82,62 +85,139 @@ struct bcm2708_fb_stats {
+       u32 dma_irqs;
+ };
++struct vc4_display_settings_t {
++      u32 display_num;
++      u32 width;
++      u32 height;
++      u32 pitch;
++      u32 depth;
++      u32 virtual_width;
++      u32 virtual_height;
++      u32 virtual_width_offset;
++      u32 virtual_height_offset;
++      unsigned long fb_bus_address;
++};
++
++struct bcm2708_fb_dev;
++
+ struct bcm2708_fb {
+       struct fb_info fb;
+       struct platform_device *dev;
+-      struct rpi_firmware *fw;
+       u32 cmap[16];
+       u32 gpu_cmap[256];
++      struct dentry *debugfs_dir;
++      struct dentry *debugfs_subdir;
++      unsigned long fb_bus_address;
++      struct { u32 base, length; } gpu;
++      struct vc4_display_settings_t display_settings;
++      struct debugfs_regset32 screeninfo_regset;
++      struct bcm2708_fb_dev *fbdev;
++      unsigned int image_size;
++      dma_addr_t dma_addr;
++      void *cpuaddr;
++};
++
++#define MAX_FRAMEBUFFERS 3
++
++struct bcm2708_fb_dev {
++      int firmware_supports_multifb;
++      /* Protects the DMA system from multiple FB access */
++      struct mutex dma_mutex;
+       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;
+-      unsigned long fb_bus_address;
+-      struct { u32 base, length; } gpu;
++      bool disable_arm_alloc;
++      struct bcm2708_fb_stats dma_stats;
++      void *cb_base;  /* DMA control blocks */
++      dma_addr_t cb_handle;
++      int instance_count;
++      int num_displays;
++      struct rpi_firmware *fw;
++      struct bcm2708_fb displays[MAX_FRAMEBUFFERS];
+ };
+ #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;
++      debugfs_remove_recursive(fb->debugfs_subdir);
++      fb->debugfs_subdir = NULL;
++
++      fb->fbdev->instance_count--;
++
++      if (!fb->fbdev->instance_count) {
++              debugfs_remove_recursive(fb->debugfs_dir);
++              fb->debugfs_dir = NULL;
++      }
+ }
+ static int bcm2708_fb_debugfs_init(struct bcm2708_fb *fb)
+ {
++      char buf[3];
++      struct bcm2708_fb_dev *fbdev = fb->fbdev;
++
+       static struct debugfs_reg32 stats_registers[] = {
+-              {
+-                      "dma_copies",
+-                      offsetof(struct bcm2708_fb_stats, dma_copies)
+-              },
+-              {
+-                      "dma_irqs",
+-                      offsetof(struct bcm2708_fb_stats, dma_irqs)
+-              },
++      {"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);
++      static struct debugfs_reg32 screeninfo[] = {
++      {"width",        offsetof(struct fb_var_screeninfo, xres)},
++      {"height",       offsetof(struct fb_var_screeninfo, yres)},
++      {"bpp",          offsetof(struct fb_var_screeninfo, bits_per_pixel)},
++      {"xres_virtual", offsetof(struct fb_var_screeninfo, xres_virtual)},
++      {"yres_virtual", offsetof(struct fb_var_screeninfo, yres_virtual)},
++      {"xoffset",      offsetof(struct fb_var_screeninfo, xoffset)},
++      {"yoffset",      offsetof(struct fb_var_screeninfo, yoffset)},
++      };
++
++      fb->debugfs_dir = debugfs_lookup(DRIVER_NAME, NULL);
++
++      if (!fb->debugfs_dir)
++              fb->debugfs_dir = debugfs_create_dir(DRIVER_NAME, NULL);
++
+       if (!fb->debugfs_dir) {
+-              pr_warn("%s: could not create debugfs entry\n",
+-                      __func__);
++              dev_warn(fb->fb.dev, "%s: could not create debugfs folder\n",
++                       __func__);
++              return -EFAULT;
++      }
++
++      snprintf(buf, sizeof(buf), "%u", fb->display_settings.display_num);
++
++      fb->debugfs_subdir = debugfs_create_dir(buf, fb->debugfs_dir);
++
++      if (!fb->debugfs_subdir) {
++              dev_warn(fb->fb.dev, "%s: could not create debugfs entry %u\n",
++                       __func__, fb->display_settings.display_num);
+               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__);
++      fbdev->dma_stats.regset.regs = stats_registers;
++      fbdev->dma_stats.regset.nregs = ARRAY_SIZE(stats_registers);
++      fbdev->dma_stats.regset.base = &fbdev->dma_stats;
++
++      if (!debugfs_create_regset32("dma_stats", 0444, fb->debugfs_subdir,
++                                   &fbdev->dma_stats.regset)) {
++              dev_warn(fb->fb.dev, "%s: could not create statistics registers\n",
++                       __func__);
++              goto fail;
++      }
++
++      fb->screeninfo_regset.regs = screeninfo;
++      fb->screeninfo_regset.nregs = ARRAY_SIZE(screeninfo);
++      fb->screeninfo_regset.base = &fb->fb.var;
++
++      if (!debugfs_create_regset32("screeninfo", 0444, fb->debugfs_subdir,
++                                   &fb->screeninfo_regset)) {
++              dev_warn(fb->fb.dev,
++                       "%s: could not create dimensions registers\n",
++                       __func__);
+               goto fail;
+       }
++
++      fbdev->instance_count++;
++
+       return 0;
+ fail:
+@@ -145,6 +225,20 @@ fail:
+       return -EFAULT;
+ }
++static void set_display_num(struct bcm2708_fb *fb)
++{
++      if (fb && fb->fbdev && fb->fbdev->firmware_supports_multifb) {
++              u32 tmp = fb->display_settings.display_num;
++
++              if (rpi_firmware_property(fb->fbdev->fw,
++                                        RPI_FIRMWARE_FRAMEBUFFER_SET_DISPLAY_NUM,
++                                        &tmp,
++                                        sizeof(tmp)))
++                      dev_warn_once(fb->fb.dev,
++                                    "Set display number call failed. Old GPU firmware?");
++      }
++}
++
+ static int bcm2708_fb_set_bitfields(struct fb_var_screeninfo *var)
+ {
+       int ret = 0;
+@@ -222,11 +316,11 @@ static int bcm2708_fb_check_var(struct f
+                               struct fb_info *info)
+ {
+       /* info input, var output */
+-      print_debug("%s(%p) %dx%d (%dx%d), %d, %d\n",
++      print_debug("%s(%p) %ux%u (%ux%u), %ul, %u\n",
+                   __func__, info, info->var.xres, info->var.yres,
+                   info->var.xres_virtual, info->var.yres_virtual,
+-                  (int)info->screen_size, info->var.bits_per_pixel);
+-      print_debug("%s(%p) %dx%d (%dx%d), %d\n", __func__, var, var->xres,
++                  info->screen_size, info->var.bits_per_pixel);
++      print_debug("%s(%p) %ux%u (%ux%u), %u\n", __func__, var, var->xres,
+                   var->yres, var->xres_virtual, var->yres_virtual,
+                   var->bits_per_pixel);
+@@ -283,23 +377,96 @@ static int bcm2708_fb_set_par(struct fb_
+                       .xoffset = info->var.xoffset,
+                       .yoffset = info->var.yoffset,
+               .tag5 = { RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE, 8, 0 },
+-                      .base = 0,
+-                      .screen_size = 0,
+-              .tag6 = { RPI_FIRMWARE_FRAMEBUFFER_GET_PITCH, 4, 0 },
+-                      .pitch = 0,
++                      /* base and screen_size will be initialised later */
++              .tag6 = { RPI_FIRMWARE_FRAMEBUFFER_SET_PITCH, 4, 0 },
++                      /* pitch will be initialised later */
+       };
+-      int ret;
++      int ret, image_size;
++
+-      print_debug("%s(%p) %dx%d (%dx%d), %d, %d\n", __func__, info,
++      print_debug("%s(%p) %dx%d (%dx%d), %d, %d (display %d)\n", __func__,
++                  info,
+                   info->var.xres, info->var.yres, info->var.xres_virtual,
+                   info->var.yres_virtual, (int)info->screen_size,
+-                  info->var.bits_per_pixel);
++                  info->var.bits_per_pixel, value);
++
++      /* Need to set the display number to act on first
++       * Cannot do it in the tag list because on older firmware the call
++       * will fail and stop the rest of the list being executed.
++       * We can ignore this call failing as the default at other end is 0
++       */
++      set_display_num(fb);
++
++      /* Try allocating our own buffer. We can specify all the parameters */
++      image_size = ((info->var.xres * info->var.yres) *
++                    info->var.bits_per_pixel) >> 3;
++
++      if (!fb->fbdev->disable_arm_alloc &&
++          (image_size != fb->image_size || !fb->dma_addr)) {
++              if (fb->dma_addr) {
++                      dma_free_coherent(info->device, fb->image_size,
++                                        fb->cpuaddr, fb->dma_addr);
++                      fb->image_size = 0;
++                      fb->cpuaddr = NULL;
++                      fb->dma_addr = 0;
++              }
++
++              fb->cpuaddr = dma_alloc_coherent(info->device, image_size,
++                                               &fb->dma_addr, GFP_KERNEL);
++
++              if (!fb->cpuaddr) {
++                      fb->dma_addr = 0;
++                      fb->fbdev->disable_arm_alloc = true;
++              } else {
++                      fb->image_size = image_size;
++              }
++      }
++
++      if (fb->cpuaddr) {
++              fbinfo.base = fb->dma_addr;
++              fbinfo.screen_size = image_size;
++              fbinfo.pitch = (info->var.xres * info->var.bits_per_pixel) >> 3;
++
++              ret = rpi_firmware_property_list(fb->fbdev->fw, &fbinfo,
++                                               sizeof(fbinfo));
++              if (ret || fbinfo.base != fb->dma_addr) {
++                      /* Firmware either failed, or assigned a different base
++                       * address (ie it doesn't support being passed an FB
++                       * allocation).
++                       * Destroy the allocation, and don't try again.
++                       */
++                      dma_free_coherent(info->device, fb->image_size,
++                                        fb->cpuaddr, fb->dma_addr);
++                      fb->image_size = 0;
++                      fb->cpuaddr = NULL;
++                      fb->dma_addr = 0;
++                      fb->fbdev->disable_arm_alloc = true;
++              }
++      } else {
++              /* Our allocation failed - drop into the old scheme of
++               * allocation by the VPU.
++               */
++              ret = -ENOMEM;
++      }
+-      ret = rpi_firmware_property_list(fb->fw, &fbinfo, sizeof(fbinfo));
+       if (ret) {
+-              dev_err(info->device,
+-                      "Failed to allocate GPU framebuffer (%d)\n", ret);
+-              return ret;
++              /* Old scheme:
++               * - FRAMEBUFFER_ALLOCATE passes 0 for base and screen_size.
++               * - GET_PITCH instead of SET_PITCH.
++               */
++              fbinfo.base = 0;
++              fbinfo.screen_size = 0;
++              fbinfo.tag6.tag = RPI_FIRMWARE_FRAMEBUFFER_GET_PITCH;
++              fbinfo.pitch = 0;
++
++              ret = rpi_firmware_property_list(fb->fbdev->fw, &fbinfo,
++                                               sizeof(fbinfo));
++              if (ret) {
++                      dev_err(info->device,
++                              "Failed to allocate GPU framebuffer (%d)\n",
++                              ret);
++                      return ret;
++              }
+       }
+       if (info->var.bits_per_pixel <= 8)
+@@ -314,9 +481,17 @@ static int bcm2708_fb_set_par(struct fb_
+       fb->fb.fix.smem_start = fbinfo.base;
+       fb->fb.fix.smem_len = fbinfo.pitch * fbinfo.yres_virtual;
+       fb->fb.screen_size = fbinfo.screen_size;
+-      if (fb->fb.screen_base)
+-              iounmap(fb->fb.screen_base);
+-      fb->fb.screen_base = ioremap_wc(fbinfo.base, fb->fb.screen_size);
++
++      if (!fb->dma_addr) {
++              if (fb->fb.screen_base)
++                      iounmap(fb->fb.screen_base);
++
++              fb->fb.screen_base = ioremap_wc(fbinfo.base,
++                                              fb->fb.screen_size);
++      } else {
++              fb->fb.screen_base = fb->cpuaddr;
++      }
++
+       if (!fb->fb.screen_base) {
+               /* the console may currently be locked */
+               console_trylock();
+@@ -374,7 +549,10 @@ static int bcm2708_fb_setcolreg(unsigned
+                       packet->length = regno + 1;
+                       memcpy(packet->cmap, fb->gpu_cmap,
+                              sizeof(packet->cmap));
+-                      ret = rpi_firmware_property(fb->fw,
++
++                      set_display_num(fb);
++
++                      ret = rpi_firmware_property(fb->fbdev->fw,
+                                                   RPI_FIRMWARE_FRAMEBUFFER_SET_PALETTE,
+                                                   packet,
+                                                   (2 + packet->length) * sizeof(u32));
+@@ -413,8 +591,11 @@ static int bcm2708_fb_blank(int blank_mo
+               return -EINVAL;
+       }
+-      ret = rpi_firmware_property(fb->fw, RPI_FIRMWARE_FRAMEBUFFER_BLANK,
++      set_display_num(fb);
++
++      ret = rpi_firmware_property(fb->fbdev->fw, RPI_FIRMWARE_FRAMEBUFFER_BLANK,
+                                   &value, sizeof(value));
++
+       if (ret)
+               dev_err(info->device, "%s(%d) failed: %d\n", __func__,
+                       blank_mode, ret);
+@@ -431,7 +612,7 @@ static int bcm2708_fb_pan_display(struct
+       info->var.yoffset = var->yoffset;
+       result = bcm2708_fb_set_par(info);
+       if (result != 0)
+-              pr_err("%s(%d,%d) returns=%d\n", __func__, var->xoffset,
++              pr_err("%s(%u,%u) returns=%d\n", __func__, var->xoffset,
+                      var->yoffset, result);
+       return result;
+ }
+@@ -439,8 +620,9 @@ static int bcm2708_fb_pan_display(struct
+ static void dma_memcpy(struct bcm2708_fb *fb, dma_addr_t dst, dma_addr_t src,
+                      int size)
+ {
+-      int burst_size = (fb->dma_chan == 0) ? 8 : 2;
+-      struct bcm2708_dma_cb *cb = fb->cb_base;
++      struct bcm2708_fb_dev *fbdev = fb->fbdev;
++      struct bcm2708_dma_cb *cb = fbdev->cb_base;
++      int burst_size = (fbdev->dma_chan == 0) ? 8 : 2;
+       cb->info = BCM2708_DMA_BURST(burst_size) | BCM2708_DMA_S_WIDTH |
+                  BCM2708_DMA_S_INC | BCM2708_DMA_D_WIDTH |
+@@ -453,21 +635,27 @@ static void dma_memcpy(struct bcm2708_fb
+       cb->pad[1] = 0;
+       cb->next = 0;
++      // Not sure what to do if this gets a signal whilst waiting
++      if (mutex_lock_interruptible(&fbdev->dma_mutex))
++              return;
++
+       if (size < dma_busy_wait_threshold) {
+-              bcm_dma_start(fb->dma_chan_base, fb->cb_handle);
+-              bcm_dma_wait_idle(fb->dma_chan_base);
++              bcm_dma_start(fbdev->dma_chan_base, fbdev->cb_handle);
++              bcm_dma_wait_idle(fbdev->dma_chan_base);
+       } else {
+-              void __iomem *dma_chan = fb->dma_chan_base;
++              void __iomem *local_dma_chan = fbdev->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));
++              bcm_dma_start(fbdev->dma_chan_base, fbdev->cb_handle);
++              while (bcm_dma_is_busy(local_dma_chan)) {
++                      wait_event_interruptible(fbdev->dma_waitq,
++                                               !bcm_dma_is_busy(local_dma_chan));
+               }
+-              fb->stats.dma_irqs++;
++              fbdev->dma_stats.dma_irqs++;
+       }
+-      fb->stats.dma_copies++;
++      fbdev->dma_stats.dma_copies++;
++
++      mutex_unlock(&fbdev->dma_mutex);
+ }
+ /* address with no aliases */
+@@ -542,10 +730,13 @@ static int bcm2708_ioctl(struct fb_info
+       switch (cmd) {
+       case FBIO_WAITFORVSYNC:
+-              ret = rpi_firmware_property(fb->fw,
++              set_display_num(fb);
++
++              ret = rpi_firmware_property(fb->fbdev->fw,
+                                           RPI_FIRMWARE_FRAMEBUFFER_SET_VSYNC,
+                                           &dummy, sizeof(dummy));
+               break;
++
+       case FBIODMACOPY:
+       {
+               struct fb_dmacopy ioparam;
+@@ -615,23 +806,22 @@ static int bcm2708_compat_ioctl(struct f
+ static void bcm2708_fb_fillrect(struct fb_info *info,
+                               const struct fb_fillrect *rect)
+ {
+-      /* (is called) print_debug("bcm2708_fb_fillrect\n"); */
+       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)
++              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;
++              BCM2708_DMA_S_INC | BCM2708_DMA_D_WIDTH |
++              BCM2708_DMA_D_INC | BCM2708_DMA_TDMODE;
+       cb->dst = dst;
+       cb->src = src;
+       /*
+@@ -649,15 +839,19 @@ static void bcm2708_fb_copyarea(struct f
+                               const struct fb_copyarea *region)
+ {
+       struct bcm2708_fb *fb = to_bcm2708(info);
+-      struct bcm2708_dma_cb *cb = fb->cb_base;
++      struct bcm2708_fb_dev *fbdev = fb->fbdev;
++      struct bcm2708_dma_cb *cb = fbdev->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 burst_size = (fbdev->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 ||
++      /* If DMA is currently in use (ie being used on another FB), then
++       * rather than wait for it to finish, just use the cfb_copyarea
++       */
++      if (!mutex_trylock(&fbdev->dma_mutex) ||
++          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 ||
+@@ -684,8 +878,8 @@ static void bcm2708_fb_copyarea(struct f
+                * 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;
++              dma_addr_t control_block_pa = fbdev->cb_handle;
++              dma_addr_t scratchbuf = fbdev->cb_handle + 16 * 1024;
+               int scanline_size = bytes_per_pixel * region->width;
+               int scanlines_per_cb = (64 * 1024 - 16 * 1024) / scanline_size;
+@@ -735,10 +929,10 @@ static void bcm2708_fb_copyarea(struct f
+               }
+               set_dma_cb(cb, burst_size,
+                          fb->fb_bus_address + dy * fb->fb.fix.line_length +
+-                                                 bytes_per_pixel * region->dx,
++                         bytes_per_pixel * region->dx,
+                          stride,
+                          fb->fb_bus_address + sy * fb->fb.fix.line_length +
+-                                                 bytes_per_pixel * region->sx,
++                         bytes_per_pixel * region->sx,
+                          stride,
+                          region->width * bytes_per_pixel,
+                          region->height);
+@@ -748,32 +942,33 @@ static void bcm2708_fb_copyarea(struct f
+       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);
++              bcm_dma_start(fbdev->dma_chan_base, fbdev->cb_handle);
++              bcm_dma_wait_idle(fbdev->dma_chan_base);
+       } else {
+-              void __iomem *dma_chan = fb->dma_chan_base;
++              void __iomem *local_dma_chan = fbdev->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));
++              bcm_dma_start(fbdev->dma_chan_base, fbdev->cb_handle);
++              while (bcm_dma_is_busy(local_dma_chan)) {
++                      wait_event_interruptible(fbdev->dma_waitq,
++                                               !bcm_dma_is_busy(local_dma_chan));
+               }
+-              fb->stats.dma_irqs++;
++              fbdev->dma_stats.dma_irqs++;
+       }
+-      fb->stats.dma_copies++;
++      fbdev->dma_stats.dma_copies++;
++
++      mutex_unlock(&fbdev->dma_mutex);
+ }
+ static void bcm2708_fb_imageblit(struct fb_info *info,
+                                const struct fb_image *image)
+ {
+-      /* (is called) print_debug("bcm2708_fb_imageblit\n"); */
+       cfb_imageblit(info, image);
+ }
+ static irqreturn_t bcm2708_fb_dma_irq(int irq, void *cxt)
+ {
+-      struct bcm2708_fb *fb = cxt;
++      struct bcm2708_fb_dev *fbdev = cxt;
+       /* FIXME: should read status register to check if this is
+        * actually interrupting us or not, in case this interrupt
+@@ -783,9 +978,9 @@ static irqreturn_t bcm2708_fb_dma_irq(in
+        */
+       /* acknowledge the interrupt */
+-      writel(BCM2708_DMA_INT, fb->dma_chan_base + BCM2708_DMA_CS);
++      writel(BCM2708_DMA_INT, fbdev->dma_chan_base + BCM2708_DMA_CS);
+-      wake_up(&fb->dma_waitq);
++      wake_up(&fbdev->dma_waitq);
+       return IRQ_HANDLED;
+ }
+@@ -821,11 +1016,23 @@ static int bcm2708_fb_register(struct bc
+       fb->fb.fix.ywrapstep = 0;
+       fb->fb.fix.accel = FB_ACCEL_NONE;
+-      fb->fb.var.xres = fbwidth;
+-      fb->fb.var.yres = fbheight;
+-      fb->fb.var.xres_virtual = fbwidth;
+-      fb->fb.var.yres_virtual = fbheight;
+-      fb->fb.var.bits_per_pixel = fbdepth;
++      /* If we have data from the VC4 on FB's, use that, otherwise use the
++       * module parameters
++       */
++      if (fb->display_settings.width) {
++              fb->fb.var.xres = fb->display_settings.width;
++              fb->fb.var.yres = fb->display_settings.height;
++              fb->fb.var.xres_virtual = fb->fb.var.xres;
++              fb->fb.var.yres_virtual = fb->fb.var.yres;
++              fb->fb.var.bits_per_pixel = fb->display_settings.depth;
++      } else {
++              fb->fb.var.xres = fbwidth;
++              fb->fb.var.yres = fbheight;
++              fb->fb.var.xres_virtual = fbwidth;
++              fb->fb.var.yres_virtual = fbheight;
++              fb->fb.var.bits_per_pixel = fbdepth;
++      }
++
+       fb->fb.var.vmode = FB_VMODE_NONINTERLACED;
+       fb->fb.var.activate = FB_ACTIVATE_NOW;
+       fb->fb.var.nonstd = 0;
+@@ -841,26 +1048,23 @@ static int bcm2708_fb_register(struct bc
+       fb->fb.monspecs.dclkmax = 100000000;
+       bcm2708_fb_set_bitfields(&fb->fb.var);
+-      init_waitqueue_head(&fb->dma_waitq);
+       /*
+        * Allocate colourmap.
+        */
+-
+       fb_set_var(&fb->fb, &fb->fb.var);
++
+       ret = bcm2708_fb_set_par(&fb->fb);
++
+       if (ret)
+               return ret;
+-      print_debug("BCM2708FB: registering framebuffer (%dx%d@%d) (%d)\n",
+-                  fbwidth, fbheight, fbdepth, fbswap);
+-
+       ret = register_framebuffer(&fb->fb);
+-      print_debug("BCM2708FB: register framebuffer (%d)\n", ret);
++
+       if (ret == 0)
+               goto out;
+-      print_debug("BCM2708FB: cannot register framebuffer (%d)\n", ret);
++      dev_warn(fb->fb.dev, "Unable to register framebuffer (%d)\n", ret);
+ out:
+       return ret;
+ }
+@@ -869,10 +1073,18 @@ static int bcm2708_fb_probe(struct platf
+ {
+       struct device_node *fw_np;
+       struct rpi_firmware *fw;
+-      struct bcm2708_fb *fb;
+-      int ret;
++      int ret, i;
++      u32 num_displays;
++      struct bcm2708_fb_dev *fbdev;
++      struct { u32 base, length; } gpu_mem;
++
++      fbdev = devm_kzalloc(&dev->dev, sizeof(*fbdev), GFP_KERNEL);
++
++      if (!fbdev)
++              return -ENOMEM;
+       fw_np = of_parse_phandle(dev->dev.of_node, "firmware", 0);
++
+ /* Remove comment when booting without Device Tree is no longer supported
+  *    if (!fw_np) {
+  *            dev_err(&dev->dev, "Missing firmware node\n");
+@@ -880,90 +1092,154 @@ static int bcm2708_fb_probe(struct platf
+  *    }
+  */
+       fw = rpi_firmware_get(fw_np);
++      fbdev->fw = fw;
++
+       if (!fw)
+               return -EPROBE_DEFER;
+-      fb = kzalloc(sizeof(*fb), GFP_KERNEL);
+-      if (!fb) {
+-              ret = -ENOMEM;
+-              goto free_region;
++      ret = rpi_firmware_property(fw,
++                                  RPI_FIRMWARE_FRAMEBUFFER_GET_NUM_DISPLAYS,
++                                  &num_displays, sizeof(u32));
++
++      /* If we fail to get the number of displays, or it returns 0, then
++       * assume old firmware that doesn't have the mailbox call, so just
++       * set one display
++       */
++      if (ret || num_displays == 0) {
++              num_displays = 1;
++              dev_err(&dev->dev,
++                      "Unable to determine number of FB's. Assuming 1\n");
++              ret = 0;
++      } else {
++              fbdev->firmware_supports_multifb = 1;
+       }
+-      fb->fw = fw;
+-      bcm2708_fb_debugfs_init(fb);
++      if (num_displays > MAX_FRAMEBUFFERS) {
++              dev_warn(&dev->dev,
++                       "More displays reported from firmware than supported in driver (%u vs %u)",
++                       num_displays, MAX_FRAMEBUFFERS);
++              num_displays = MAX_FRAMEBUFFERS;
++      }
+-      fb->cb_base = dma_alloc_writecombine(&dev->dev, SZ_64K,
+-                                           &fb->cb_handle, GFP_KERNEL);
+-      if (!fb->cb_base) {
++      dev_info(&dev->dev, "FB found %d display(s)\n", num_displays);
++
++      /* Set up the DMA information. Note we have just one set of DMA
++       * parameters to work with all the FB's so requires synchronising when
++       * being used
++       */
++
++      mutex_init(&fbdev->dma_mutex);
++
++      fbdev->cb_base = dma_alloc_writecombine(&dev->dev, SZ_64K,
++                                              &fbdev->cb_handle,
++                                              GFP_KERNEL);
++      if (!fbdev->cb_base) {
+               dev_err(&dev->dev, "cannot allocate DMA CBs\n");
+               ret = -ENOMEM;
+               goto free_fb;
+       }
+-      pr_info("BCM2708FB: allocated DMA memory %pad\n", &fb->cb_handle);
+-
+       ret = bcm_dma_chan_alloc(BCM_DMA_FEATURE_BULK,
+-                               &fb->dma_chan_base, &fb->dma_irq);
++                               &fbdev->dma_chan_base,
++                               &fbdev->dma_irq);
+       if (ret < 0) {
+-              dev_err(&dev->dev, "couldn't allocate a DMA channel\n");
++              dev_err(&dev->dev, "Couldn't allocate a DMA channel\n");
+               goto free_cb;
+       }
+-      fb->dma_chan = ret;
++      fbdev->dma_chan = ret;
+-      ret = request_irq(fb->dma_irq, bcm2708_fb_dma_irq,
+-                        0, "bcm2708_fb dma", fb);
++      ret = request_irq(fbdev->dma_irq, bcm2708_fb_dma_irq,
++                        0, "bcm2708_fb DMA", fbdev);
+       if (ret) {
+-              pr_err("%s: failed to request DMA irq\n", __func__);
++              dev_err(&dev->dev,
++                      "Failed to request DMA irq\n");
+               goto free_dma_chan;
+       }
+-      pr_info("BCM2708FB: allocated DMA channel %d\n", fb->dma_chan);
++      rpi_firmware_property(fbdev->fw,
++                            RPI_FIRMWARE_GET_VC_MEMORY,
++                            &gpu_mem, sizeof(gpu_mem));
++
++      for (i = 0; i < num_displays; i++) {
++              struct bcm2708_fb *fb = &fbdev->displays[i];
++
++              fb->display_settings.display_num = i;
++              fb->dev = dev;
++              fb->fb.device = &dev->dev;
++              fb->fbdev = fbdev;
++
++              fb->gpu.base = gpu_mem.base;
++              fb->gpu.length = gpu_mem.length;
++
++              if (fbdev->firmware_supports_multifb) {
++                      ret = rpi_firmware_property(fw,
++                                                  RPI_FIRMWARE_FRAMEBUFFER_GET_DISPLAY_SETTINGS,
++                                                  &fb->display_settings,
++                                                  GET_DISPLAY_SETTINGS_PAYLOAD_SIZE);
++              } else {
++                      memset(&fb->display_settings, 0,
++                             sizeof(fb->display_settings));
++              }
++
++              ret = bcm2708_fb_register(fb);
+-      fb->dev = dev;
+-      fb->fb.device = &dev->dev;
++              if (ret == 0) {
++                      bcm2708_fb_debugfs_init(fb);
+-      /* failure here isn't fatal, but we'll fail in vc_mem_copy if
+-       * fb->gpu is not valid
+-       */
+-      rpi_firmware_property(fb->fw, RPI_FIRMWARE_GET_VC_MEMORY, &fb->gpu,
+-                            sizeof(fb->gpu));
++                      fbdev->num_displays++;
+-      ret = bcm2708_fb_register(fb);
+-      if (ret == 0) {
+-              platform_set_drvdata(dev, fb);
+-              goto out;
++                      dev_info(&dev->dev,
++                               "Registered framebuffer for display %u, size %ux%u\n",
++                               fb->display_settings.display_num,
++                               fb->fb.var.xres,
++                               fb->fb.var.yres);
++              } else {
++                      // Use this to flag if this FB entry is in use.
++                      fb->fbdev = NULL;
++              }
++      }
++
++      // Did we actually successfully create any FB's?
++      if (fbdev->num_displays) {
++              init_waitqueue_head(&fbdev->dma_waitq);
++              platform_set_drvdata(dev, fbdev);
++              return ret;
+       }
+ free_dma_chan:
+-      bcm_dma_chan_free(fb->dma_chan);
++      bcm_dma_chan_free(fbdev->dma_chan);
+ free_cb:
+-      dma_free_writecombine(&dev->dev, SZ_64K, fb->cb_base, fb->cb_handle);
++      dma_free_writecombine(&dev->dev, SZ_64K, fbdev->cb_base,
++                            fbdev->cb_handle);
+ free_fb:
+-      kfree(fb);
+-free_region:
+       dev_err(&dev->dev, "probe failed, err %d\n", ret);
+-out:
++
+       return ret;
+ }
+ static int bcm2708_fb_remove(struct platform_device *dev)
+ {
+-      struct bcm2708_fb *fb = platform_get_drvdata(dev);
++      struct bcm2708_fb_dev *fbdev = platform_get_drvdata(dev);
++      int i;
+       platform_set_drvdata(dev, NULL);
+-      if (fb->fb.screen_base)
+-              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);
+-
+-      bcm2708_fb_debugfs_deinit(fb);
++      for (i = 0; i < fbdev->num_displays; i++) {
++              if (fbdev->displays[i].fb.screen_base)
++                      iounmap(fbdev->displays[i].fb.screen_base);
++
++              if (fbdev->displays[i].fbdev) {
++                      unregister_framebuffer(&fbdev->displays[i].fb);
++                      bcm2708_fb_debugfs_deinit(&fbdev->displays[i]);
++              }
++      }
+-      free_irq(fb->dma_irq, fb);
++      dma_free_writecombine(&dev->dev, SZ_64K, fbdev->cb_base,
++                            fbdev->cb_handle);
++      bcm_dma_chan_free(fbdev->dma_chan);
++      free_irq(fbdev->dma_irq, fbdev);
+-      kfree(fb);
++      mutex_destroy(&fbdev->dma_mutex);
+       return 0;
+ }
+@@ -978,10 +1254,10 @@ static struct platform_driver bcm2708_fb
+       .probe = bcm2708_fb_probe,
+       .remove = bcm2708_fb_remove,
+       .driver = {
+-                 .name = DRIVER_NAME,
+-                 .owner = THIS_MODULE,
+-                 .of_match_table = bcm2708_fb_of_match_table,
+-                 },
++                .name = DRIVER_NAME,
++                .owner = THIS_MODULE,
++                .of_match_table = bcm2708_fb_of_match_table,
++                },
+ };
+ static int __init bcm2708_fb_init(void)
+--- a/include/soc/bcm2835/raspberrypi-firmware.h
++++ b/include/soc/bcm2835/raspberrypi-firmware.h
+@@ -138,9 +138,11 @@ enum rpi_firmware_property_tag {
+       RPI_FIRMWARE_FRAMEBUFFER_SET_DEPTH =                  0x00048005,
+       RPI_FIRMWARE_FRAMEBUFFER_SET_PIXEL_ORDER =            0x00048006,
+       RPI_FIRMWARE_FRAMEBUFFER_SET_ALPHA_MODE =             0x00048007,
++      RPI_FIRMWARE_FRAMEBUFFER_SET_PITCH =                  0x00048008,
+       RPI_FIRMWARE_FRAMEBUFFER_SET_VIRTUAL_OFFSET =         0x00048009,
+       RPI_FIRMWARE_FRAMEBUFFER_SET_OVERSCAN =               0x0004800a,
+       RPI_FIRMWARE_FRAMEBUFFER_SET_PALETTE =                0x0004800b,
++
+       RPI_FIRMWARE_FRAMEBUFFER_SET_TOUCHBUF =               0x0004801f,
+       RPI_FIRMWARE_FRAMEBUFFER_SET_GPIOVIRTBUF =            0x00048020,
+       RPI_FIRMWARE_FRAMEBUFFER_SET_VSYNC =                  0x0004800e,
+@@ -159,6 +161,8 @@ enum rpi_firmware_property_tag {
+       RPI_FIRMWARE_GET_DMA_CHANNELS =                       0x00060001,
+ };
++#define GET_DISPLAY_SETTINGS_PAYLOAD_SIZE 64
++
+ #if IS_ENABLED(CONFIG_RASPBERRYPI_FIRMWARE)
+ int rpi_firmware_property(struct rpi_firmware *fw,
+                         u32 tag, void *data, size_t len);