drm/etnaviv: Add PPU flop reset

The PPU flop reset is required on some hardware to clear the
temporary registers. This code follows the implementation
of the PPU flop reset as found in the public galcore kernel
module. Compared to that code some superfluous parts were
removed and only the code path for SoC chip_model = 0x8000
and revision = 0x6205 is implemented and tested.

v2: - Move flop reset data to etnaviv_drm_private and initialize it
      from etnaviv_gpu_bind (Lucas)
    - Prepare code for more chip IDs and other flop reset types
    - Do some cleanups and rename some functions

v3: - Move initialization of flop reset data to etnaviv_gpu_init (Lucas)
    - Free PPU data suballocation (Lucas)

v4: As suggested by
    - replace "asm-generic/int-ll64.h" with "linux/types.h"
    - drop flop reset type enum since we only support one type here
    - move function return parameters on same line with function name
    - replace open coded for loop with memset32
    - add cnost to local static values
    - add a return value to etnaviv_flop_reset_ppu_init; handle and
      pass errors on to the caller
    - handle etnaviv_flop_reset_ppu_init return value
    - use dev_err for flop reset error message
    - fix include guard to be consistent with the other driver code
    - fix license header and formatting

v5: As suggested by Christian Gmeiner:
    - add required header that is no longer pulled in by etnaviv_buffer.h
    - fix include style of linux headers
    - free flop_reset_data_ppu when command buffer initialization fails
    - fix typo in error message

[cgmeiner: fix SPDX comment style, fix line end with a '(' and fix typo]

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Christian Gmeiner <cgmeiner@igalia.com>
Tested-by: Marek Vasut <marek.vasut@mailbox.org> # STM32MP255C DHCOS DHSBC
Link: https://patch.msgid.link/20251119164624.9297-5-gert.wollny@collabora.com
Signed-off-by: Christian Gmeiner <cgmeiner@igalia.com>

8 files changed, 260 insertions, 0 deletions

diff --git a/drivers/gpu/drm/etnaviv/Makefile b/drivers/gpu/drm/etnaviv/Makefile
index 46e5ffad69a6..903101e8751a 100644
--- a/drivers/gpu/drm/etnaviv/Makefile
+++ b/drivers/gpu/drm/etnaviv/Makefile
@@ -14,6 +14,7 @@ etnaviv-y := \
 	etnaviv_iommu.o \
 	etnaviv_mmu.o \
 	etnaviv_perfmon.o \
+	etnaviv_flop_reset.o \
 	etnaviv_sched.o
 
 obj-$(CONFIG_DRM_ETNAVIV)	+= etnaviv.o
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_buffer.c b/drivers/gpu/drm/etnaviv/etnaviv_buffer.c
index e99b1c9e66e4..03b2576af67f 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_buffer.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_buffer.c
@@ -19,6 +19,8 @@
 #include "state_3d.xml.h"
 #include "cmdstream.xml.h"
 
+#include "etnaviv_flop_reset.h"
+
 static void etnaviv_cmd_select_pipe(struct etnaviv_gpu *gpu,
 	struct etnaviv_cmdbuf *buffer, u8 pipe)
 {
@@ -101,6 +103,10 @@ u16 etnaviv_buffer_init(struct etnaviv_gpu *gpu)
 	/* initialize buffer */
 	buffer->user_size = 0;
 
+	/* Queue in PPU flop reset */
+	if (etnaviv_flop_reset_ppu_require(&gpu->identity))
+		etnaviv_flop_reset_ppu_run(gpu);
+
 	CMD_WAIT(buffer, gpu->fe_waitcycles);
 	CMD_LINK(buffer, 2,
 		 etnaviv_cmdbuf_get_va(buffer, &gpu->mmu_context->cmdbuf_mapping)
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_buffer.h b/drivers/gpu/drm/etnaviv/etnaviv_buffer.h
index 9f9eb4d545a2..4331ca8aac47 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_buffer.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_buffer.h
@@ -7,9 +7,16 @@
 #define __ETNAVIV_BUFFER_H__
 
 #include "etnaviv_cmdbuf.h"
+#include "etnaviv_gpu.h"
+#include "etnaviv_gem.h"
+#include "etnaviv_mmu.h"
 
 #include "common.xml.h"
+#include "linux/printk.h"
 #include "state.xml.h"
+#include "state_blt.xml.h"
+#include "state_hi.xml.h"
+#include "state_3d.xml.h"
 #include "cmdstream.xml.h"
 
 static inline void OUT(struct etnaviv_cmdbuf *buffer, u32 data)
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
index 54ceae87b401..bb1b84eecec8 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
@@ -601,6 +601,9 @@ static void etnaviv_unbind(struct device *dev)
 
 	component_unbind_all(dev, drm);
 
+	etnaviv_cmdbuf_free(priv->flop_reset_data_ppu);
+	kfree(priv->flop_reset_data_ppu);
+
 	etnaviv_cmdbuf_suballoc_destroy(priv->cmdbuf_suballoc);
 
 	xa_destroy(&priv->active_contexts);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.h b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
index b3eb1662e90c..20dad16fd554 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_drv.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
@@ -48,6 +48,9 @@ struct etnaviv_drm_private {
 	/* list of GEM objects: */
 	struct mutex gem_lock;
 	struct list_head gem_list;
+
+	/* ppu flop reset data */
+	struct etnaviv_cmdbuf *flop_reset_data_ppu;
 };
 
 int etnaviv_ioctl_gem_submit(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_flop_reset.c b/drivers/gpu/drm/etnaviv/etnaviv_flop_reset.c
new file mode 100644
index 000000000000..2ae6532a51ab
--- /dev/null
+++ b/drivers/gpu/drm/etnaviv/etnaviv_flop_reset.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025 Etnaviv Project
+ */
+
+#include <linux/errno.h>
+#include <linux/dev_printk.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include "etnaviv_buffer.h"
+#include "etnaviv_cmdbuf.h"
+#include "etnaviv_gpu.h"
+#include "state_3d.xml.h"
+
+#include "etnaviv_flop_reset.h"
+
+#define PPU_IMAGE_STRIDE 64
+#define PPU_IMAGE_XSIZE 64
+#define PPU_IMAGE_YSIZE 6
+
+#define PPU_FLOP_RESET_INSTR_DWORD_COUNT 16
+
+static void etnaviv_emit_flop_reset_state_ppu(struct etnaviv_cmdbuf *cmdbuf,
+					      u32 buffer_base, u32 input_offset,
+					      u32 output_offset,
+					      u32 shader_offset,
+					      u32 shader_size,
+					      u32 shader_register_count)
+{
+	CMD_LOAD_STATE(cmdbuf, VIVS_GL_API_MODE, VIVS_GL_API_MODE_OPENCL);
+	CMD_SEM(cmdbuf, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
+	CMD_STALL(cmdbuf, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
+
+	CMD_LOAD_STATES_START(cmdbuf, VIVS_SH_HALTI5_UNIFORMS(0), 4);
+
+	OUT(cmdbuf, buffer_base + input_offset);
+	OUT(cmdbuf, PPU_IMAGE_STRIDE);
+	OUT(cmdbuf, PPU_IMAGE_XSIZE | (PPU_IMAGE_YSIZE << 16));
+	OUT(cmdbuf, 0x444051f0);
+	OUT(cmdbuf, 0xffffffff);
+
+	CMD_LOAD_STATES_START(cmdbuf, VIVS_SH_HALTI5_UNIFORMS(4), 4);
+	OUT(cmdbuf, buffer_base + output_offset);
+	OUT(cmdbuf, PPU_IMAGE_STRIDE);
+	OUT(cmdbuf, PPU_IMAGE_XSIZE | (PPU_IMAGE_YSIZE << 16));
+	OUT(cmdbuf, 0x444051f0);
+	OUT(cmdbuf, 0xffffffff);
+
+	CMD_LOAD_STATE(cmdbuf, VIVS_CL_CONFIG,
+		       VIVS_CL_CONFIG_DIMENSIONS(2) |
+			       VIVS_CL_CONFIG_VALUE_ORDER(3));
+	CMD_LOAD_STATE(cmdbuf, VIVS_VS_ICACHE_INVALIDATE, 0x1f);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_VARYING_NUM_COMPONENTS(0), 0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_TEMP_REGISTER_CONTROL,
+		       shader_register_count);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_SAMPLER_BASE, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_UNIFORM_BASE, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_NEWRANGE_LOW, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_NEWRANGE_HIGH, shader_size / 16);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_INST_ADDR, buffer_base + shader_offset);
+	CMD_LOAD_STATE(cmdbuf, VIVS_SH_CONFIG, VIVS_SH_CONFIG_RTNE_ROUNDING);
+	CMD_LOAD_STATE(cmdbuf, VIVS_VS_ICACHE_CONTROL,
+		       VIVS_VS_ICACHE_CONTROL_ENABLE);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_ICACHE_COUNT, shader_size / 16 - 1);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_INPUT_COUNT, 0x1f01);
+	CMD_LOAD_STATE(cmdbuf, VIVS_VS_HALTI5_UNK008A0, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PA_VS_OUTPUT_COUNT, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_GL_VARYING_TOTAL_COMPONENTS, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_CONTROL_EXT, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_VS_OUTPUT_COUNT, 0x1);
+	CMD_LOAD_STATE(cmdbuf, VIVS_GL_HALTI5_SH_SPECIALS, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_PS_ICACHE_PREFETCH, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_CL_UNK00924, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_CL_THREAD_ALLOCATION, 0x1);
+
+	CMD_LOAD_STATE(cmdbuf, VIVS_CL_GLOBAL_WORK_OFFSET_X, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_CL_GLOBAL_WORK_OFFSET_Y, 0x0);
+	CMD_LOAD_STATE(cmdbuf, VIVS_CL_GLOBAL_WORK_OFFSET_Z, 0x0);
+
+	CMD_LOAD_STATES_START(cmdbuf, VIVS_CL_WORKGROUP_COUNT_X, 9);
+	OUT(cmdbuf, 0xf);
+	OUT(cmdbuf, 0x5);
+	OUT(cmdbuf, 0xffffffff);
+	OUT(cmdbuf, 0x0);
+	OUT(cmdbuf, 0x0);
+	OUT(cmdbuf, 0x3ff);
+	OUT(cmdbuf, 0x0);
+	OUT(cmdbuf, 0x4);
+	OUT(cmdbuf, 0x1);
+	OUT(cmdbuf, 0x0);
+
+	CMD_LOAD_STATE(cmdbuf, VIVS_CL_KICKER, 0xbadabeeb);
+	CMD_LOAD_STATE(cmdbuf, VIVS_GL_FLUSH_CACHE,
+		       VIVS_GL_FLUSH_CACHE_SHADER_L1 |
+			       VIVS_GL_FLUSH_CACHE_UNK10 |
+			       VIVS_GL_FLUSH_CACHE_UNK11);
+}
+
+static void etnaviv_flop_reset_ppu_fill_input(u32 *buffer, u32 size)
+{
+	memset32(buffer, 0x01010101, size / 4);
+}
+
+static void etnaviv_flop_reset_ppu_set_shader(u8 *dest)
+{
+	static const u32 inst[PPU_FLOP_RESET_INSTR_DWORD_COUNT] = {
+		/* img_load.u8 r1, c0, r0.xy */
+		0x78011779,
+		0x39000804,
+		0x00A90050,
+		0x00000000,
+		/* img_load.u8 r2, c0, r0.xy */
+		0x78021779,
+		0x39000804,
+		0x00A90050,
+		0x00000000,
+		/* dp2x8 r1, r1, r2, c3_512 */
+		0xB8017145,
+		0x390018FC,
+		0x01C90140,
+		0x40390028,
+		/* img_store.u8 r1, c2, r0.xy, r1 */
+		0x380007BA,
+		0x39001804,
+		0x00A90050,
+		0x00390018,
+	};
+	memcpy(dest, inst, sizeof(inst));
+}
+
+static const struct etnaviv_flop_reset_entry {
+	u16 chip_model;
+	u16 revision;
+	u32 flags;
+} etnaviv_flop_reset_db[] = {
+	{
+		.chip_model = 0x8000,
+		.revision = 0x6205,
+	},
+};
+
+bool etnaviv_flop_reset_ppu_require(const struct etnaviv_chip_identity *chip_id)
+{
+	const struct etnaviv_flop_reset_entry *e = etnaviv_flop_reset_db;
+
+	for (int i = 0; i < ARRAY_SIZE(etnaviv_flop_reset_db); ++i, ++e) {
+		if (chip_id->model == e->chip_model &&
+		    chip_id->revision == e->revision)
+			return true;
+	}
+
+	return false;
+}
+
+static const u32 image_data_size = PPU_IMAGE_STRIDE * PPU_IMAGE_YSIZE;
+static const u32 output_offset = ALIGN(image_data_size, 64);
+static const u32 shader_offset = ALIGN(output_offset + image_data_size, 64);
+static const u32 shader_size = PPU_FLOP_RESET_INSTR_DWORD_COUNT * sizeof(u32);
+static const u32 shader_register_count = 3;
+static const u32 buffer_size = shader_offset + shader_size;
+
+int etnaviv_flop_reset_ppu_init(struct etnaviv_drm_private *priv)
+{
+	/* Get some space from the ring buffer to put the payload
+	 * (input and output image, and shader), we keep this buffer
+	 * for the whole life time the driver is bound
+	 */
+	priv->flop_reset_data_ppu =
+		kzalloc(sizeof(*priv->flop_reset_data_ppu), GFP_KERNEL);
+
+	if (!priv->flop_reset_data_ppu)
+		return -ENOMEM;
+
+	int ret = etnaviv_cmdbuf_init(priv->cmdbuf_suballoc,
+				      priv->flop_reset_data_ppu, buffer_size);
+	if (ret) {
+		kfree(priv->flop_reset_data_ppu);
+		return ret;
+	}
+
+	void *buffer_base = priv->flop_reset_data_ppu->vaddr;
+	u32 *input_data = (u32 *)buffer_base;
+	u8 *shader_data = (u8 *)buffer_base + shader_offset;
+
+	etnaviv_flop_reset_ppu_fill_input(input_data, image_data_size);
+	etnaviv_flop_reset_ppu_set_shader(shader_data);
+
+	return 0;
+}
+
+void etnaviv_flop_reset_ppu_run(struct etnaviv_gpu *gpu)
+{
+	struct etnaviv_drm_private *priv = gpu->drm->dev_private;
+
+	if (!priv->flop_reset_data_ppu) {
+		dev_err(gpu->dev,
+			"Oops: Flop reset data was not initialized, skipping\n");
+		return;
+	}
+
+	u32 buffer_base = etnaviv_cmdbuf_get_va(priv->flop_reset_data_ppu,
+						&gpu->mmu_context->cmdbuf_mapping);
+
+	etnaviv_emit_flop_reset_state_ppu(&gpu->buffer, buffer_base, 0,
+					  output_offset, shader_offset,
+					  shader_size, shader_register_count);
+}
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_flop_reset.h b/drivers/gpu/drm/etnaviv/etnaviv_flop_reset.h
new file mode 100644
index 000000000000..e6dee1db788f
--- /dev/null
+++ b/drivers/gpu/drm/etnaviv/etnaviv_flop_reset.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2025 Etnaviv Project
+ */
+
+#ifndef _ETNAVIV_FLOP_RESET_H_
+#define _ETNAVIV_FLOP_RESET_H_
+
+#include <linux/types.h>
+
+struct etnaviv_chip_identity;
+struct etnaviv_drm_private;
+struct etnaviv_gpu;
+
+bool etnaviv_flop_reset_ppu_require(const struct etnaviv_chip_identity *chip_id);
+
+int etnaviv_flop_reset_ppu_init(struct etnaviv_drm_private *priv);
+
+void etnaviv_flop_reset_ppu_run(struct etnaviv_gpu *gpu);
+
+#endif
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index ca0be293f5fe..94326dddaf6f 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -20,6 +20,7 @@
 
 #include "etnaviv_cmdbuf.h"
 #include "etnaviv_dump.h"
+#include "etnaviv_flop_reset.h"
 #include "etnaviv_gpu.h"
 #include "etnaviv_gem.h"
 #include "etnaviv_mmu.h"
@@ -839,6 +840,16 @@ int etnaviv_gpu_init(struct etnaviv_gpu *gpu)
 		goto fail;
 	}
 
+	if (etnaviv_flop_reset_ppu_require(&gpu->identity) &&
+	    !priv->flop_reset_data_ppu) {
+		ret = etnaviv_flop_reset_ppu_init(priv);
+		if (ret) {
+			dev_err(gpu->dev,
+				"Unable to initialize PPU flop reset data\n");
+			goto fail;
+		}
+	}
+
 	if (gpu->identity.nn_core_count > 0)
 		dev_warn(gpu->dev, "etnaviv has been instantiated on a NPU, "
                                    "for which the UAPI is still experimental\n");