drm/sprd: add Unisoc's drm display controller driver

Adds DPU(Display Processor Unit) support for the Unisoc's display
subsystem.
It's support multi planes, scaler, rotation, PQ(Picture Quality) and more.

v2:
  - Use drm_xxx to replace all DRM_XXX.
  - Use kzalloc to replace devm_kzalloc for sprd_dpu structure init.

v3:
  - Remove dpu_layer stuff layer and commit layers by aotmic_update

v4:
  - Use drmm_helpers to allocate crtc and planes.
  - Move rotation enum definitions to crtc layer reg bitfields.
  - Move allocate crtc and planes to bind function.

v5:
  - Fix the checkpatch warnings.
  - Use mode_set_nofb instead of mode_valid callback.
  - Follow the OF-Graph bindings, use of_graph_get_port_by_id
    instead of of_parse_phandle.
  - Use zpos to represent the layer position.
  - Rebase to last drm misc branch.

v6:
  - Disable and clear interrupts before register dpu IRQ
  - Init dpi config used by crtc_state->adjusted_mode on mode_set_nofb
  - Remove enable_irq and disable_irq function call.
  - Remove drm_format_info function call.

v7:
  - Remove iommu error interrupt handling function.

Cc: Orson Zhai <orsonzhai@gmail.com>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Signed-off-by: Kevin Tang <kevin.tang@unisoc.com>
Reviewed-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211207142717.30296-5-kevin3.tang@gmail.com

drivers/gpu/drm/sprd/Kconfig

@@ -5,6 +5,7 @@ config DRM_SPRD
 	select DRM_GEM_CMA_HELPER
 	select DRM_KMS_CMA_HELPER
 	select DRM_KMS_HELPER
+	select VIDEOMODE_HELPERS
 	help
 	  Choose this option if you have a Unisoc chipset.
 	  If M is selected the module will be called sprd_drm.

drivers/gpu/drm/sprd/Makefile

 # SPDX-License-Identifier: GPL-2.0
 
-obj-y := sprd_drm.o
+obj-y := sprd_drm.o \
+	sprd_dpu.o

drivers/gpu/drm/sprd/sprd_dpu.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020 Unisoc Inc.
+ */
+
+#ifndef __SPRD_DPU_H__
+#define __SPRD_DPU_H__
+
+#include <linux/bug.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/string.h>
+#include <video/videomode.h>
+
+#include <drm/drm_crtc.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_print.h>
+#include <drm/drm_vblank.h>
+#include <uapi/drm/drm_mode.h>
+
+/* DPU Layer registers offset */
+#define DPU_LAY_REG_OFFSET	0x30
+
+enum {
+	SPRD_DPU_IF_DPI,
+	SPRD_DPU_IF_EDPI,
+	SPRD_DPU_IF_LIMIT
+};
+
+/**
+ * Sprd DPU context structure
+ *
+ * @base: DPU controller base address
+ * @irq: IRQ number to install the handler for
+ * @if_type: The type of DPI interface, default is DPI mode.
+ * @vm: videomode structure to use for DPU and DPI initialization
+ * @stopped: indicates whether DPU are stopped
+ * @wait_queue: wait queue, used to wait for DPU shadow register update done and
+ * DPU stop register done interrupt signal.
+ * @evt_update: wait queue condition for DPU shadow register
+ * @evt_stop: wait queue condition for DPU stop register
+ */
+struct dpu_context {
+	void __iomem *base;
+	int irq;
+	u8 if_type;
+	struct videomode vm;
+	bool stopped;
+	wait_queue_head_t wait_queue;
+	bool evt_update;
+	bool evt_stop;
+};
+
+/**
+ * Sprd DPU device structure
+ *
+ * @crtc: crtc object
+ * @drm: A point to drm device
+ * @ctx: DPU's implementation specific context object
+ */
+struct sprd_dpu {
+	struct drm_crtc base;
+	struct drm_device *drm;
+	struct dpu_context ctx;
+};
+
+static inline struct sprd_dpu *to_sprd_crtc(struct drm_crtc *crtc)
+{
+	return container_of(crtc, struct sprd_dpu, base);
+}
+
+static inline void
+dpu_reg_set(struct dpu_context *ctx, u32 offset, u32 set_bits)
+{
+	u32 bits = readl_relaxed(ctx->base + offset);
+
+	writel(bits | set_bits, ctx->base + offset);
+}
+
+static inline void
+dpu_reg_clr(struct dpu_context *ctx, u32 offset, u32 clr_bits)
+{
+	u32 bits = readl_relaxed(ctx->base + offset);
+
+	writel(bits & ~clr_bits, ctx->base + offset);
+}
+
+static inline u32
+layer_reg_rd(struct dpu_context *ctx, u32 offset, int index)
+{
+	u32 layer_offset = offset + index * DPU_LAY_REG_OFFSET;
+
+	return readl(ctx->base + layer_offset);
+}
+
+static inline void
+layer_reg_wr(struct dpu_context *ctx, u32 offset, u32 cfg_bits, int index)
+{
+	u32 layer_offset =  offset + index * DPU_LAY_REG_OFFSET;
+
+	writel(cfg_bits, ctx->base + layer_offset);
+}
+
+void sprd_dpu_run(struct sprd_dpu *dpu);
+void sprd_dpu_stop(struct sprd_dpu *dpu);
+
+#endif

drivers/gpu/drm/sprd/sprd_drm.c

@@ -180,6 +180,7 @@ static struct platform_driver sprd_drm_driver = {
 
 static struct platform_driver *sprd_drm_drivers[]  = {
 	&sprd_drm_driver,
+	&sprd_dpu_driver,
 };
 
 static int __init sprd_drm_init(void)

drivers/gpu/drm/sprd/sprd_drm.h

@@ -13,4 +13,6 @@ struct sprd_drm {
 	struct drm_device drm;
 };
 
+extern struct platform_driver sprd_dpu_driver;
+
 #endif /* _SPRD_DRM_H_ */