drm/msm/dpu: Add dpu_hw_cwb abstraction for CWB block

The CWB mux has its own registers and set of operations. Add dpu_hw_cwb
abstraction to allow driver to configure the CWB mux.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/629254/
Link: https://lore.kernel.org/r/20241216-concurrent-wb-v4-12-fe220297a7f0@quicinc.com
[DB: added #include <linux/bitfield.h>]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Author: Jessica Zhang

drivers/gpu/drm/msm/Makefile

@@ -78,6 +78,7 @@ msm-display-$(CONFIG_DRM_MSM_DPU) += \
 	disp/dpu1/dpu_hw_catalog.o \
 	disp/dpu1/dpu_hw_cdm.o \
 	disp/dpu1/dpu_hw_ctl.o \
+	disp/dpu1/dpu_hw_cwb.o \
 	disp/dpu1/dpu_hw_dsc.o \
 	disp/dpu1/dpu_hw_dsc_1_2.o \
 	disp/dpu1/dpu_hw_interrupts.o \

drivers/gpu/drm/msm/disp/dpu1/dpu_hw_cwb.c

@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved
+ */
+
+#include <drm/drm_managed.h>
+#include "dpu_hw_cwb.h"
+
+#include <linux/bitfield.h>
+
+#define CWB_MUX              0x000
+#define CWB_MODE             0x004
+
+/* CWB mux block bit definitions */
+#define CWB_MUX_MASK         GENMASK(3, 0)
+#define CWB_MODE_MASK        GENMASK(2, 0)
+
+static void dpu_hw_cwb_config(struct dpu_hw_cwb *ctx,
+			      struct dpu_hw_cwb_setup_cfg *cwb_cfg)
+{
+	struct dpu_hw_blk_reg_map *c = &ctx->hw;
+	int cwb_mux_cfg = 0xF;
+	enum dpu_pingpong pp;
+	enum cwb_mode_input input;
+
+	if (!cwb_cfg)
+		return;
+
+	input = cwb_cfg->input;
+	pp = cwb_cfg->pp_idx;
+
+	if (input >= INPUT_MODE_MAX)
+		return;
+
+	/*
+	 * The CWB_MUX register takes the pingpong index for the real-time
+	 * display
+	 */
+	if ((pp != PINGPONG_NONE) && (pp < PINGPONG_MAX))
+		cwb_mux_cfg = FIELD_PREP(CWB_MUX_MASK, pp - PINGPONG_0);
+
+	input = FIELD_PREP(CWB_MODE_MASK, input);
+
+	DPU_REG_WRITE(c, CWB_MUX, cwb_mux_cfg);
+	DPU_REG_WRITE(c, CWB_MODE, input);
+}
+
+/**
+ * dpu_hw_cwb_init() - Initializes the writeback hw driver object with cwb.
+ * @dev:  Corresponding device for devres management
+ * @cfg:  wb_path catalog entry for which driver object is required
+ * @addr: mapped register io address of MDP
+ * Return: Error code or allocated dpu_hw_wb context
+ */
+struct dpu_hw_cwb *dpu_hw_cwb_init(struct drm_device *dev,
+				   const struct dpu_cwb_cfg *cfg,
+				   void __iomem *addr)
+{
+	struct dpu_hw_cwb *c;
+
+	if (!addr)
+		return ERR_PTR(-EINVAL);
+
+	c = drmm_kzalloc(dev, sizeof(*c), GFP_KERNEL);
+	if (!c)
+		return ERR_PTR(-ENOMEM);
+
+	c->hw.blk_addr = addr + cfg->base;
+	c->hw.log_mask = DPU_DBG_MASK_CWB;
+
+	c->idx = cfg->id;
+	c->ops.config_cwb = dpu_hw_cwb_config;
+
+	return c;
+}

drivers/gpu/drm/msm/disp/dpu1/dpu_hw_cwb.h

@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved
+ */
+
+#ifndef _DPU_HW_CWB_H
+#define _DPU_HW_CWB_H
+
+#include "dpu_hw_util.h"
+
+struct dpu_hw_cwb;
+
+enum cwb_mode_input {
+	INPUT_MODE_LM_OUT,
+	INPUT_MODE_DSPP_OUT,
+	INPUT_MODE_MAX
+};
+
+/**
+ * struct dpu_hw_cwb_setup_cfg : Describes configuration for CWB mux
+ * @pp_idx:        Index of the real-time pinpong that the CWB mux will
+ *                 feed the CWB mux
+ * @input:         Input tap point
+ */
+struct dpu_hw_cwb_setup_cfg {
+	enum dpu_pingpong pp_idx;
+	enum cwb_mode_input input;
+};
+
+/**
+ *
+ * struct dpu_hw_cwb_ops : Interface to the cwb hw driver functions
+ * @config_cwb: configure CWB mux
+ */
+struct dpu_hw_cwb_ops {
+	void (*config_cwb)(struct dpu_hw_cwb *ctx,
+			   struct dpu_hw_cwb_setup_cfg *cwb_cfg);
+};
+
+/**
+ * struct dpu_hw_cwb : CWB mux driver object
+ * @base: Hardware block base structure
+ * @hw: Block hardware details
+ * @idx: CWB index
+ * @ops: handle to operations possible for this CWB
+ */
+struct dpu_hw_cwb {
+	struct dpu_hw_blk base;
+	struct dpu_hw_blk_reg_map hw;
+
+	enum dpu_cwb idx;
+
+	struct dpu_hw_cwb_ops ops;
+};
+
+/**
+ * dpu_hw_cwb - convert base object dpu_hw_base to container
+ * @hw: Pointer to base hardware block
+ * return: Pointer to hardware block container
+ */
+static inline struct dpu_hw_cwb *to_dpu_hw_cwb(struct dpu_hw_blk *hw)
+{
+	return container_of(hw, struct dpu_hw_cwb, base);
+}
+
+struct dpu_hw_cwb *dpu_hw_cwb_init(struct drm_device *dev,
+				   const struct dpu_cwb_cfg *cfg,
+				   void __iomem *addr);
+
+#endif /*_DPU_HW_CWB_H */

drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
-/* Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.
+/*
+ * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.
  */
 
 #ifndef _DPU_HW_MDSS_H
@@ -350,6 +352,7 @@ struct dpu_mdss_color {
 #define DPU_DBG_MASK_DSPP     (1 << 10)
 #define DPU_DBG_MASK_DSC      (1 << 11)
 #define DPU_DBG_MASK_CDM      (1 << 12)
+#define DPU_DBG_MASK_CWB      (1 << 13)
 
 /**
  * struct dpu_hw_tear_check - Struct contains parameters to configure