drm: samsung: support fb handover

Fb handover keeps a memory region for a frame from bootloader.
This patch supports fb handover and controls reserved memory.

Bug: 202947589
Test: Enable continuous splash
Signed-off-by: Kwanghyun Chung <khyun.chung@samsung.com>
Signed-off-by: Leo Chen <yinchiuan@google.com>
(Cherry picked from commit 6164fbadf3ddbd87861a0d31f267398e8da485d8)

Change-Id: I83189598c84a29cd06b7842520bf667f430b4f18

1 files changed, 77 insertions, 0 deletions

diff --git a/samsung/exynos_drm_fb.c b/samsung/exynos_drm_fb.c
index 73183e1..d9c1770 100644
--- a/samsung/exynos_drm_fb.c
+++ b/samsung/exynos_drm_fb.c
@@ -24,6 +24,7 @@
 #include <uapi/linux/videodev2_exynos_media.h>
 #include <linux/dma-buf.h>
 #include <linux/pm_runtime.h>
+#include <linux/of_reserved_mem.h>
 
 #include <trace/dpu_trace.h>
 
@@ -469,6 +470,80 @@ static void exynos_atomic_bts_post_update(struct drm_device *dev,
 	}
 }
 
+/*
+ * rmem_device_init is called in of_reserved_mem_device_init_by_idx function
+ * when reserved memory is required.
+ */
+static int rmem_device_init(struct reserved_mem *rmem, struct device *dev)
+{
+	struct decon_device *decon = dev_get_drvdata(dev);
+
+	decon->fb_handover.phys_addr = rmem->base;
+	decon->fb_handover.phys_size = rmem->size;
+	pr_debug("%s base(%pa) size(%pa)\n", __func__, &decon->fb_handover.phys_addr,
+			&decon->fb_handover.phys_size);
+
+	return 0;
+}
+
+/*
+ * rmem_device_release is called in of_reserved_mem_device_release function
+ * when reserved memory is no longer required.
+ */
+static void rmem_device_release(struct reserved_mem *rmem, struct device *dev)
+{
+	struct page *first = phys_to_page(PAGE_ALIGN(rmem->base));
+	struct page *last = phys_to_page((rmem->base + rmem->size) & PAGE_MASK);
+	struct page *page;
+
+	for (page = first; page != last; page++) {
+		__ClearPageReserved(page);
+		set_page_count(page, 1);
+		__free_pages(page, 0);
+		adjust_managed_page_count(page, 1);
+	}
+}
+
+static const struct reserved_mem_ops rmem_ops = {
+	.device_init    = rmem_device_init,
+	.device_release = rmem_device_release,
+};
+
+void exynos_rmem_register(struct decon_device *decon)
+{
+	struct device_node *np, *rmem_np;
+	struct reserved_mem *rmem;
+	struct device *dev = decon->dev;
+
+	np = dev->of_node;
+
+	rmem_np = of_parse_phandle(np, "memory-region", 0);
+	if (!rmem_np) {
+		pr_debug("failed to get reserve memory phandle\n");
+		return;
+	}
+
+	rmem = of_reserved_mem_lookup(rmem_np);
+	if (!rmem) {
+		pr_err("failed to reserve memory lookup\n");
+		return;
+	}
+
+	of_node_put(rmem_np);
+	rmem->ops = &rmem_ops;
+	decon->fb_handover.rmem = rmem;
+	of_reserved_mem_device_init_by_idx(dev, np, 0);
+}
+
+static void exynos_rmem_free(struct decon_device *decon)
+{
+	of_reserved_mem_device_release(decon->dev);
+
+	decon->fb_handover.rmem = NULL;
+	decon->fb_handover.phys_size = 0;
+}
+
+
 static void exynos_atomic_commit_tail(struct drm_atomic_state *old_state)
 {
 	int i;
@@ -617,6 +692,8 @@ static void exynos_atomic_commit_tail(struct drm_atomic_state *old_state)
 		decon = crtc_to_decon(crtc);
 		if (disabling_crtc_mask & drm_crtc_mask(crtc))
 			pm_runtime_put_sync(decon->dev);
+		if (new_crtc_state->plane_mask && decon->fb_handover.rmem)
+			exynos_rmem_free(decon);
 	}
 
 	drm_atomic_helper_commit_hw_done(old_state);