drivers/gpu/drm/etnaviv/etnaviv_buffer.c - linux-mtk - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2014-2018 Etnaviv Project
  */

 #include "etnaviv_cmdbuf.h"
 #include "etnaviv_gpu.h"
 #include "etnaviv_gem.h"
 #include "etnaviv_mmu.h"

 #include "common.xml.h"
 #include "state.xml.h"
 #include "state_hi.xml.h"
 #include "state_3d.xml.h"
 #include "cmdstream.xml.h"

 /*
  * Command Buffer helper:
  */


 static inline void OUT(struct etnaviv_cmdbuf *buffer, u32 data)
 {
 	u32 *vaddr = (u32 *)buffer->vaddr;

 	BUG_ON(buffer->user_size >= buffer->size);

 	vaddr[buffer->user_size / 4] = data;
 	buffer->user_size += 4;
 }

 static inline void CMD_LOAD_STATE(struct etnaviv_cmdbuf *buffer,
 	u32 reg, u32 value)
 {
 	u32 index = reg >> VIV_FE_LOAD_STATE_HEADER_OFFSET__SHR;

 	buffer->user_size = ALIGN(buffer->user_size, 8);

 	/* write a register via cmd stream */
 	OUT(buffer, VIV_FE_LOAD_STATE_HEADER_OP_LOAD_STATE |
 		    VIV_FE_LOAD_STATE_HEADER_COUNT(1) |
 		    VIV_FE_LOAD_STATE_HEADER_OFFSET(index));
 	OUT(buffer, value);
 }

 static inline void CMD_END(struct etnaviv_cmdbuf *buffer)
 {
 	buffer->user_size = ALIGN(buffer->user_size, 8);

 	OUT(buffer, VIV_FE_END_HEADER_OP_END);
 }

 static inline void CMD_WAIT(struct etnaviv_cmdbuf *buffer)
 {
 	buffer->user_size = ALIGN(buffer->user_size, 8);

 	OUT(buffer, VIV_FE_WAIT_HEADER_OP_WAIT | 200);
 }

 static inline void CMD_LINK(struct etnaviv_cmdbuf *buffer,
 	u16 prefetch, u32 address)
 {
 	buffer->user_size = ALIGN(buffer->user_size, 8);

 	OUT(buffer, VIV_FE_LINK_HEADER_OP_LINK |
 		    VIV_FE_LINK_HEADER_PREFETCH(prefetch));
 	OUT(buffer, address);
 }

 static inline void CMD_STALL(struct etnaviv_cmdbuf *buffer,
 	u32 from, u32 to)
 {
 	buffer->user_size = ALIGN(buffer->user_size, 8);

 	OUT(buffer, VIV_FE_STALL_HEADER_OP_STALL);
 	OUT(buffer, VIV_FE_STALL_TOKEN_FROM(from) | VIV_FE_STALL_TOKEN_TO(to));
 }

 static inline void CMD_SEM(struct etnaviv_cmdbuf *buffer, u32 from, u32 to)
 {
 	CMD_LOAD_STATE(buffer, VIVS_GL_SEMAPHORE_TOKEN,
 		       VIVS_GL_SEMAPHORE_TOKEN_FROM(from) |
 		       VIVS_GL_SEMAPHORE_TOKEN_TO(to));
 }

 static void etnaviv_cmd_select_pipe(struct etnaviv_gpu *gpu,
 	struct etnaviv_cmdbuf *buffer, u8 pipe)
 {
 	u32 flush = 0;

 	lockdep_assert_held(&gpu->lock);

 	/*
 	 * This assumes that if we're switching to 2D, we're switching
 	 * away from 3D, and vice versa.  Hence, if we're switching to
 	 * the 2D core, we need to flush the 3D depth and color caches,
 	 * otherwise we need to flush the 2D pixel engine cache.
 	 */
 	if (gpu->exec_state == ETNA_PIPE_2D)
 		flush = VIVS_GL_FLUSH_CACHE_PE2D;
 	else if (gpu->exec_state == ETNA_PIPE_3D)
 		flush = VIVS_GL_FLUSH_CACHE_DEPTH | VIVS_GL_FLUSH_CACHE_COLOR;

 	CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_CACHE, flush);
 	CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 	CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);

 	CMD_LOAD_STATE(buffer, VIVS_GL_PIPE_SELECT,
 		       VIVS_GL_PIPE_SELECT_PIPE(pipe));
 }

 static void etnaviv_buffer_dump(struct etnaviv_gpu *gpu,
 	struct etnaviv_cmdbuf *buf, u32 off, u32 len)
 {
 	u32 size = buf->size;
 	u32 *ptr = buf->vaddr + off;

 	dev_info(gpu->dev, "virt %p phys 0x%08x free 0x%08x\n",
 			ptr, etnaviv_cmdbuf_get_va(buf) + off, size - len * 4 - off);

 	print_hex_dump(KERN_INFO, "cmd ", DUMP_PREFIX_OFFSET, 16, 4,
 			ptr, len * 4, 0);
 }

 /*
  * Safely replace the WAIT of a waitlink with a new command and argument.
  * The GPU may be executing this WAIT while we're modifying it, so we have
  * to write it in a specific order to avoid the GPU branching to somewhere
  * else.  'wl_offset' is the offset to the first byte of the WAIT command.
  */
 static void etnaviv_buffer_replace_wait(struct etnaviv_cmdbuf *buffer,
 	unsigned int wl_offset, u32 cmd, u32 arg)
 {
 	u32 *lw = buffer->vaddr + wl_offset;

 	lw[1] = arg;
 	mb();
 	lw[0] = cmd;
 	mb();
 }

 /*
  * Ensure that there is space in the command buffer to contiguously write
  * 'cmd_dwords' 64-bit words into the buffer, wrapping if necessary.
  */
 static u32 etnaviv_buffer_reserve(struct etnaviv_gpu *gpu,
 	struct etnaviv_cmdbuf *buffer, unsigned int cmd_dwords)
 {
 	if (buffer->user_size + cmd_dwords * sizeof(u64) > buffer->size)
 		buffer->user_size = 0;

 	return etnaviv_cmdbuf_get_va(buffer) + buffer->user_size;
 }

 u16 etnaviv_buffer_init(struct etnaviv_gpu *gpu)
 {
 	struct etnaviv_cmdbuf *buffer = &gpu->buffer;

 	lockdep_assert_held(&gpu->lock);

 	/* initialize buffer */
 	buffer->user_size = 0;

 	CMD_WAIT(buffer);
 	CMD_LINK(buffer, 2, etnaviv_cmdbuf_get_va(buffer) +
 		 buffer->user_size - 4);

 	return buffer->user_size / 8;
 }

 u16 etnaviv_buffer_config_mmuv2(struct etnaviv_gpu *gpu, u32 mtlb_addr, u32 safe_addr)
 {
 	struct etnaviv_cmdbuf *buffer = &gpu->buffer;

 	lockdep_assert_held(&gpu->lock);

 	buffer->user_size = 0;

 	if (gpu->identity.features & chipFeatures_PIPE_3D) {
 		CMD_LOAD_STATE(buffer, VIVS_GL_PIPE_SELECT,
 			       VIVS_GL_PIPE_SELECT_PIPE(ETNA_PIPE_3D));
 		CMD_LOAD_STATE(buffer, VIVS_MMUv2_CONFIGURATION,
 			mtlb_addr | VIVS_MMUv2_CONFIGURATION_MODE_MODE4_K);
 		CMD_LOAD_STATE(buffer, VIVS_MMUv2_SAFE_ADDRESS, safe_addr);
 		CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 		CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 	}

 	if (gpu->identity.features & chipFeatures_PIPE_2D) {
 		CMD_LOAD_STATE(buffer, VIVS_GL_PIPE_SELECT,
 			       VIVS_GL_PIPE_SELECT_PIPE(ETNA_PIPE_2D));
 		CMD_LOAD_STATE(buffer, VIVS_MMUv2_CONFIGURATION,
 			mtlb_addr | VIVS_MMUv2_CONFIGURATION_MODE_MODE4_K);
 		CMD_LOAD_STATE(buffer, VIVS_MMUv2_SAFE_ADDRESS, safe_addr);
 		CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 		CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 	}

 	CMD_END(buffer);

 	buffer->user_size = ALIGN(buffer->user_size, 8);

 	return buffer->user_size / 8;
 }

 u16 etnaviv_buffer_config_pta(struct etnaviv_gpu *gpu)
 {
 	struct etnaviv_cmdbuf *buffer = &gpu->buffer;

 	lockdep_assert_held(&gpu->lock);

 	buffer->user_size = 0;

 	CMD_LOAD_STATE(buffer, VIVS_MMUv2_PTA_CONFIG,
 		       VIVS_MMUv2_PTA_CONFIG_INDEX(0));

 	CMD_END(buffer);

 	buffer->user_size = ALIGN(buffer->user_size, 8);

 	return buffer->user_size / 8;
 }

 void etnaviv_buffer_end(struct etnaviv_gpu *gpu)
 {
 	struct etnaviv_cmdbuf *buffer = &gpu->buffer;
 	unsigned int waitlink_offset = buffer->user_size - 16;
 	u32 link_target, flush = 0;

 	lockdep_assert_held(&gpu->lock);

 	if (gpu->exec_state == ETNA_PIPE_2D)
 		flush = VIVS_GL_FLUSH_CACHE_PE2D;
 	else if (gpu->exec_state == ETNA_PIPE_3D)
 		flush = VIVS_GL_FLUSH_CACHE_DEPTH |
 			VIVS_GL_FLUSH_CACHE_COLOR |
 			VIVS_GL_FLUSH_CACHE_TEXTURE |
 			VIVS_GL_FLUSH_CACHE_TEXTUREVS |
 			VIVS_GL_FLUSH_CACHE_SHADER_L2;

 	if (flush) {
 		unsigned int dwords = 7;

 		link_target = etnaviv_buffer_reserve(gpu, buffer, dwords);

 		CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 		CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 		CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_CACHE, flush);
 		if (gpu->exec_state == ETNA_PIPE_3D)
 			CMD_LOAD_STATE(buffer, VIVS_TS_FLUSH_CACHE,
 				       VIVS_TS_FLUSH_CACHE_FLUSH);
 		CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 		CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 		CMD_END(buffer);

 		etnaviv_buffer_replace_wait(buffer, waitlink_offset,
 					    VIV_FE_LINK_HEADER_OP_LINK |
 					    VIV_FE_LINK_HEADER_PREFETCH(dwords),
 					    link_target);
 	} else {
 		/* Replace the last link-wait with an "END" command */
 		etnaviv_buffer_replace_wait(buffer, waitlink_offset,
 					    VIV_FE_END_HEADER_OP_END, 0);
 	}
 }

 /* Append a 'sync point' to the ring buffer. */
 void etnaviv_sync_point_queue(struct etnaviv_gpu *gpu, unsigned int event)
 {
 	struct etnaviv_cmdbuf *buffer = &gpu->buffer;
 	unsigned int waitlink_offset = buffer->user_size - 16;
 	u32 dwords, target;

 	lockdep_assert_held(&gpu->lock);

 	/*
 	 * We need at most 3 dwords in the return target:
 	 * 1 event + 1 end + 1 wait + 1 link.
 	 */
 	dwords = 4;
 	target = etnaviv_buffer_reserve(gpu, buffer, dwords);

 	/* Signal sync point event */
 	CMD_LOAD_STATE(buffer, VIVS_GL_EVENT, VIVS_GL_EVENT_EVENT_ID(event) |
 		       VIVS_GL_EVENT_FROM_PE);

 	/* Stop the FE to 'pause' the GPU */
 	CMD_END(buffer);

 	/* Append waitlink */
 	CMD_WAIT(buffer);
 	CMD_LINK(buffer, 2, etnaviv_cmdbuf_get_va(buffer) +
 			    buffer->user_size - 4);

 	/*
 	 * Kick off the 'sync point' command by replacing the previous
 	 * WAIT with a link to the address in the ring buffer.
 	 */
 	etnaviv_buffer_replace_wait(buffer, waitlink_offset,
 				    VIV_FE_LINK_HEADER_OP_LINK |
 				    VIV_FE_LINK_HEADER_PREFETCH(dwords),
 				    target);
 }

 /* Append a command buffer to the ring buffer. */
 void etnaviv_buffer_queue(struct etnaviv_gpu *gpu, u32 exec_state,
 	unsigned int event, struct etnaviv_cmdbuf *cmdbuf)
 {
 	struct etnaviv_cmdbuf *buffer = &gpu->buffer;
 	unsigned int waitlink_offset = buffer->user_size - 16;
 	u32 return_target, return_dwords;
 	u32 link_target, link_dwords;
 	bool switch_context = gpu->exec_state != exec_state;
 	unsigned int new_flush_seq = READ_ONCE(gpu->mmu->flush_seq);
 	bool need_flush = gpu->flush_seq != new_flush_seq;

 	lockdep_assert_held(&gpu->lock);

 	if (drm_debug & DRM_UT_DRIVER)
 		etnaviv_buffer_dump(gpu, buffer, 0, 0x50);

 	link_target = etnaviv_cmdbuf_get_va(cmdbuf);
 	link_dwords = cmdbuf->size / 8;

 	/*
 	 * If we need maintanence prior to submitting this buffer, we will
 	 * need to append a mmu flush load state, followed by a new
 	 * link to this buffer - a total of four additional words.
 	 */
 	if (need_flush || switch_context) {
 		u32 target, extra_dwords;

 		/* link command */
 		extra_dwords = 1;

 		/* flush command */
 		if (need_flush) {
 			if (gpu->mmu->version == ETNAVIV_IOMMU_V1)
 				extra_dwords += 1;
 			else
 				extra_dwords += 3;
 		}

 		/* pipe switch commands */
 		if (switch_context)
 			extra_dwords += 4;

 		target = etnaviv_buffer_reserve(gpu, buffer, extra_dwords);

 		if (need_flush) {
 			/* Add the MMU flush */
 			if (gpu->mmu->version == ETNAVIV_IOMMU_V1) {
 				CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_MMU,
 					       VIVS_GL_FLUSH_MMU_FLUSH_FEMMU |
 					       VIVS_GL_FLUSH_MMU_FLUSH_UNK1 |
 					       VIVS_GL_FLUSH_MMU_FLUSH_UNK2 |
 					       VIVS_GL_FLUSH_MMU_FLUSH_PEMMU |
 					       VIVS_GL_FLUSH_MMU_FLUSH_UNK4);
 			} else {
 				CMD_LOAD_STATE(buffer, VIVS_MMUv2_CONFIGURATION,
 					VIVS_MMUv2_CONFIGURATION_MODE_MASK |
 					VIVS_MMUv2_CONFIGURATION_ADDRESS_MASK |
 					VIVS_MMUv2_CONFIGURATION_FLUSH_FLUSH);
 				CMD_SEM(buffer, SYNC_RECIPIENT_FE,
 					SYNC_RECIPIENT_PE);
 				CMD_STALL(buffer, SYNC_RECIPIENT_FE,
 					SYNC_RECIPIENT_PE);
 			}

 			gpu->flush_seq = new_flush_seq;
 		}

 		if (switch_context) {
 			etnaviv_cmd_select_pipe(gpu, buffer, exec_state);
 			gpu->exec_state = exec_state;
 		}

 		/* And the link to the submitted buffer */
 		CMD_LINK(buffer, link_dwords, link_target);

 		/* Update the link target to point to above instructions */
 		link_target = target;
 		link_dwords = extra_dwords;
 	}

 	/*
 	 * Append a LINK to the submitted command buffer to return to
 	 * the ring buffer.  return_target is the ring target address.
 	 * We need at most 7 dwords in the return target: 2 cache flush +
 	 * 2 semaphore stall + 1 event + 1 wait + 1 link.
 	 */
 	return_dwords = 7;
 	return_target = etnaviv_buffer_reserve(gpu, buffer, return_dwords);
 	CMD_LINK(cmdbuf, return_dwords, return_target);

 	/*
 	 * Append a cache flush, stall, event, wait and link pointing back to
 	 * the wait command to the ring buffer.
 	 */
 	if (gpu->exec_state == ETNA_PIPE_2D) {
 		CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_CACHE,
 				       VIVS_GL_FLUSH_CACHE_PE2D);
 	} else {
 		CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_CACHE,
 				       VIVS_GL_FLUSH_CACHE_DEPTH |
 				       VIVS_GL_FLUSH_CACHE_COLOR);
 		CMD_LOAD_STATE(buffer, VIVS_TS_FLUSH_CACHE,
 				       VIVS_TS_FLUSH_CACHE_FLUSH);
 	}
 	CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 	CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
 	CMD_LOAD_STATE(buffer, VIVS_GL_EVENT, VIVS_GL_EVENT_EVENT_ID(event) |
 		       VIVS_GL_EVENT_FROM_PE);
 	CMD_WAIT(buffer);
 	CMD_LINK(buffer, 2, etnaviv_cmdbuf_get_va(buffer) +
 			    buffer->user_size - 4);

 	if (drm_debug & DRM_UT_DRIVER)
 		pr_info("stream link to 0x%08x @ 0x%08x %p\n",
 			return_target, etnaviv_cmdbuf_get_va(cmdbuf),
 			cmdbuf->vaddr);

 	if (drm_debug & DRM_UT_DRIVER) {
 		print_hex_dump(KERN_INFO, "cmd ", DUMP_PREFIX_OFFSET, 16, 4,
 			       cmdbuf->vaddr, cmdbuf->size, 0);

 		pr_info("link op: %p\n", buffer->vaddr + waitlink_offset);
 		pr_info("addr: 0x%08x\n", link_target);
 		pr_info("back: 0x%08x\n", return_target);
 		pr_info("event: %d\n", event);
 	}

 	/*
 	 * Kick off the submitted command by replacing the previous
 	 * WAIT with a link to the address in the ring buffer.
 	 */
 	etnaviv_buffer_replace_wait(buffer, waitlink_offset,
 				    VIV_FE_LINK_HEADER_OP_LINK |
 				    VIV_FE_LINK_HEADER_PREFETCH(link_dwords),
 				    link_target);

 	if (drm_debug & DRM_UT_DRIVER)
 		etnaviv_buffer_dump(gpu, buffer, 0, 0x50);

 	gpu->lastctx = cmdbuf->ctx;
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright (C) 2014-2018 Etnaviv Project
	*/

	#include "etnaviv_cmdbuf.h"
	#include "etnaviv_gpu.h"
	#include "etnaviv_gem.h"
	#include "etnaviv_mmu.h"

	#include "common.xml.h"
	#include "state.xml.h"
	#include "state_hi.xml.h"
	#include "state_3d.xml.h"
	#include "cmdstream.xml.h"

	/*
	* Command Buffer helper:
	*/


	static inline void OUT(struct etnaviv_cmdbuf *buffer, u32 data)
	{
	u32 vaddr = (u32 )buffer->vaddr;

	BUG_ON(buffer->user_size >= buffer->size);

	vaddr[buffer->user_size / 4] = data;
	buffer->user_size += 4;
	}

	static inline void CMD_LOAD_STATE(struct etnaviv_cmdbuf *buffer,
	u32 reg, u32 value)
	{
	u32 index = reg >> VIV_FE_LOAD_STATE_HEADER_OFFSET__SHR;

	buffer->user_size = ALIGN(buffer->user_size, 8);

	/* write a register via cmd stream */
	OUT(buffer, VIV_FE_LOAD_STATE_HEADER_OP_LOAD_STATE \|
	VIV_FE_LOAD_STATE_HEADER_COUNT(1) \|
	VIV_FE_LOAD_STATE_HEADER_OFFSET(index));
	OUT(buffer, value);
	}

	static inline void CMD_END(struct etnaviv_cmdbuf *buffer)
	{
	buffer->user_size = ALIGN(buffer->user_size, 8);

	OUT(buffer, VIV_FE_END_HEADER_OP_END);
	}

	static inline void CMD_WAIT(struct etnaviv_cmdbuf *buffer)
	{
	buffer->user_size = ALIGN(buffer->user_size, 8);

	OUT(buffer, VIV_FE_WAIT_HEADER_OP_WAIT \| 200);
	}

	static inline void CMD_LINK(struct etnaviv_cmdbuf *buffer,
	u16 prefetch, u32 address)
	{
	buffer->user_size = ALIGN(buffer->user_size, 8);

	OUT(buffer, VIV_FE_LINK_HEADER_OP_LINK \|
	VIV_FE_LINK_HEADER_PREFETCH(prefetch));
	OUT(buffer, address);
	}

	static inline void CMD_STALL(struct etnaviv_cmdbuf *buffer,
	u32 from, u32 to)
	{
	buffer->user_size = ALIGN(buffer->user_size, 8);

	OUT(buffer, VIV_FE_STALL_HEADER_OP_STALL);
	OUT(buffer, VIV_FE_STALL_TOKEN_FROM(from) \| VIV_FE_STALL_TOKEN_TO(to));
	}

	static inline void CMD_SEM(struct etnaviv_cmdbuf *buffer, u32 from, u32 to)
	{
	CMD_LOAD_STATE(buffer, VIVS_GL_SEMAPHORE_TOKEN,
	VIVS_GL_SEMAPHORE_TOKEN_FROM(from) \|
	VIVS_GL_SEMAPHORE_TOKEN_TO(to));
	}

	static void etnaviv_cmd_select_pipe(struct etnaviv_gpu *gpu,
	struct etnaviv_cmdbuf *buffer, u8 pipe)
	{
	u32 flush = 0;

	lockdep_assert_held(&gpu->lock);

	/*
	* This assumes that if we're switching to 2D, we're switching
	* away from 3D, and vice versa. Hence, if we're switching to
	* the 2D core, we need to flush the 3D depth and color caches,
	* otherwise we need to flush the 2D pixel engine cache.
	*/
	if (gpu->exec_state == ETNA_PIPE_2D)
	flush = VIVS_GL_FLUSH_CACHE_PE2D;
	else if (gpu->exec_state == ETNA_PIPE_3D)
	flush = VIVS_GL_FLUSH_CACHE_DEPTH \| VIVS_GL_FLUSH_CACHE_COLOR;

	CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_CACHE, flush);
	CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);

	CMD_LOAD_STATE(buffer, VIVS_GL_PIPE_SELECT,
	VIVS_GL_PIPE_SELECT_PIPE(pipe));
	}

	static void etnaviv_buffer_dump(struct etnaviv_gpu *gpu,
	struct etnaviv_cmdbuf *buf, u32 off, u32 len)
	{
	u32 size = buf->size;
	u32 *ptr = buf->vaddr + off;

	dev_info(gpu->dev, "virt %p phys 0x%08x free 0x%08x\n",
	ptr, etnaviv_cmdbuf_get_va(buf) + off, size - len * 4 - off);

	print_hex_dump(KERN_INFO, "cmd ", DUMP_PREFIX_OFFSET, 16, 4,
	ptr, len * 4, 0);
	}

	/*
	* Safely replace the WAIT of a waitlink with a new command and argument.
	* The GPU may be executing this WAIT while we're modifying it, so we have
	* to write it in a specific order to avoid the GPU branching to somewhere
	* else. 'wl_offset' is the offset to the first byte of the WAIT command.
	*/
	static void etnaviv_buffer_replace_wait(struct etnaviv_cmdbuf *buffer,
	unsigned int wl_offset, u32 cmd, u32 arg)
	{
	u32 *lw = buffer->vaddr + wl_offset;

	lw[1] = arg;
	mb();
	lw[0] = cmd;
	mb();
	}

	/*
	* Ensure that there is space in the command buffer to contiguously write
	* 'cmd_dwords' 64-bit words into the buffer, wrapping if necessary.
	*/
	static u32 etnaviv_buffer_reserve(struct etnaviv_gpu *gpu,
	struct etnaviv_cmdbuf *buffer, unsigned int cmd_dwords)
	{
	if (buffer->user_size + cmd_dwords * sizeof(u64) > buffer->size)
	buffer->user_size = 0;

	return etnaviv_cmdbuf_get_va(buffer) + buffer->user_size;
	}

	u16 etnaviv_buffer_init(struct etnaviv_gpu *gpu)
	{
	struct etnaviv_cmdbuf *buffer = &gpu->buffer;

	lockdep_assert_held(&gpu->lock);

	/* initialize buffer */
	buffer->user_size = 0;

	CMD_WAIT(buffer);
	CMD_LINK(buffer, 2, etnaviv_cmdbuf_get_va(buffer) +
	buffer->user_size - 4);

	return buffer->user_size / 8;
	}

	u16 etnaviv_buffer_config_mmuv2(struct etnaviv_gpu *gpu, u32 mtlb_addr, u32 safe_addr)
	{
	struct etnaviv_cmdbuf *buffer = &gpu->buffer;

	lockdep_assert_held(&gpu->lock);

	buffer->user_size = 0;

	if (gpu->identity.features & chipFeatures_PIPE_3D) {
	CMD_LOAD_STATE(buffer, VIVS_GL_PIPE_SELECT,
	VIVS_GL_PIPE_SELECT_PIPE(ETNA_PIPE_3D));
	CMD_LOAD_STATE(buffer, VIVS_MMUv2_CONFIGURATION,
	mtlb_addr \| VIVS_MMUv2_CONFIGURATION_MODE_MODE4_K);
	CMD_LOAD_STATE(buffer, VIVS_MMUv2_SAFE_ADDRESS, safe_addr);
	CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	}

	if (gpu->identity.features & chipFeatures_PIPE_2D) {
	CMD_LOAD_STATE(buffer, VIVS_GL_PIPE_SELECT,
	VIVS_GL_PIPE_SELECT_PIPE(ETNA_PIPE_2D));
	CMD_LOAD_STATE(buffer, VIVS_MMUv2_CONFIGURATION,
	mtlb_addr \| VIVS_MMUv2_CONFIGURATION_MODE_MODE4_K);
	CMD_LOAD_STATE(buffer, VIVS_MMUv2_SAFE_ADDRESS, safe_addr);
	CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	}

	CMD_END(buffer);

	buffer->user_size = ALIGN(buffer->user_size, 8);

	return buffer->user_size / 8;
	}

	u16 etnaviv_buffer_config_pta(struct etnaviv_gpu *gpu)
	{
	struct etnaviv_cmdbuf *buffer = &gpu->buffer;

	lockdep_assert_held(&gpu->lock);

	buffer->user_size = 0;

	CMD_LOAD_STATE(buffer, VIVS_MMUv2_PTA_CONFIG,
	VIVS_MMUv2_PTA_CONFIG_INDEX(0));

	CMD_END(buffer);

	buffer->user_size = ALIGN(buffer->user_size, 8);

	return buffer->user_size / 8;
	}

	void etnaviv_buffer_end(struct etnaviv_gpu *gpu)
	{
	struct etnaviv_cmdbuf *buffer = &gpu->buffer;
	unsigned int waitlink_offset = buffer->user_size - 16;
	u32 link_target, flush = 0;

	lockdep_assert_held(&gpu->lock);

	if (gpu->exec_state == ETNA_PIPE_2D)
	flush = VIVS_GL_FLUSH_CACHE_PE2D;
	else if (gpu->exec_state == ETNA_PIPE_3D)
	flush = VIVS_GL_FLUSH_CACHE_DEPTH \|
	VIVS_GL_FLUSH_CACHE_COLOR \|
	VIVS_GL_FLUSH_CACHE_TEXTURE \|
	VIVS_GL_FLUSH_CACHE_TEXTUREVS \|
	VIVS_GL_FLUSH_CACHE_SHADER_L2;

	if (flush) {
	unsigned int dwords = 7;

	link_target = etnaviv_buffer_reserve(gpu, buffer, dwords);

	CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_CACHE, flush);
	if (gpu->exec_state == ETNA_PIPE_3D)
	CMD_LOAD_STATE(buffer, VIVS_TS_FLUSH_CACHE,
	VIVS_TS_FLUSH_CACHE_FLUSH);
	CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	CMD_END(buffer);

	etnaviv_buffer_replace_wait(buffer, waitlink_offset,
	VIV_FE_LINK_HEADER_OP_LINK \|
	VIV_FE_LINK_HEADER_PREFETCH(dwords),
	link_target);
	} else {
	/* Replace the last link-wait with an "END" command */
	etnaviv_buffer_replace_wait(buffer, waitlink_offset,
	VIV_FE_END_HEADER_OP_END, 0);
	}
	}

	/* Append a 'sync point' to the ring buffer. */
	void etnaviv_sync_point_queue(struct etnaviv_gpu *gpu, unsigned int event)
	{
	struct etnaviv_cmdbuf *buffer = &gpu->buffer;
	unsigned int waitlink_offset = buffer->user_size - 16;
	u32 dwords, target;

	lockdep_assert_held(&gpu->lock);

	/*
	* We need at most 3 dwords in the return target:
	* 1 event + 1 end + 1 wait + 1 link.
	*/
	dwords = 4;
	target = etnaviv_buffer_reserve(gpu, buffer, dwords);

	/* Signal sync point event */
	CMD_LOAD_STATE(buffer, VIVS_GL_EVENT, VIVS_GL_EVENT_EVENT_ID(event) \|
	VIVS_GL_EVENT_FROM_PE);

	/* Stop the FE to 'pause' the GPU */
	CMD_END(buffer);

	/* Append waitlink */
	CMD_WAIT(buffer);
	CMD_LINK(buffer, 2, etnaviv_cmdbuf_get_va(buffer) +
	buffer->user_size - 4);

	/*
	* Kick off the 'sync point' command by replacing the previous
	* WAIT with a link to the address in the ring buffer.
	*/
	etnaviv_buffer_replace_wait(buffer, waitlink_offset,
	VIV_FE_LINK_HEADER_OP_LINK \|
	VIV_FE_LINK_HEADER_PREFETCH(dwords),
	target);
	}

	/* Append a command buffer to the ring buffer. */
	void etnaviv_buffer_queue(struct etnaviv_gpu *gpu, u32 exec_state,
	unsigned int event, struct etnaviv_cmdbuf *cmdbuf)
	{
	struct etnaviv_cmdbuf *buffer = &gpu->buffer;
	unsigned int waitlink_offset = buffer->user_size - 16;
	u32 return_target, return_dwords;
	u32 link_target, link_dwords;
	bool switch_context = gpu->exec_state != exec_state;
	unsigned int new_flush_seq = READ_ONCE(gpu->mmu->flush_seq);
	bool need_flush = gpu->flush_seq != new_flush_seq;

	lockdep_assert_held(&gpu->lock);

	if (drm_debug & DRM_UT_DRIVER)
	etnaviv_buffer_dump(gpu, buffer, 0, 0x50);

	link_target = etnaviv_cmdbuf_get_va(cmdbuf);
	link_dwords = cmdbuf->size / 8;

	/*
	* If we need maintanence prior to submitting this buffer, we will
	* need to append a mmu flush load state, followed by a new
	* link to this buffer - a total of four additional words.
	*/
	if (need_flush \|\| switch_context) {
	u32 target, extra_dwords;

	/* link command */
	extra_dwords = 1;

	/* flush command */
	if (need_flush) {
	if (gpu->mmu->version == ETNAVIV_IOMMU_V1)
	extra_dwords += 1;
	else
	extra_dwords += 3;
	}

	/* pipe switch commands */
	if (switch_context)
	extra_dwords += 4;

	target = etnaviv_buffer_reserve(gpu, buffer, extra_dwords);

	if (need_flush) {
	/* Add the MMU flush */
	if (gpu->mmu->version == ETNAVIV_IOMMU_V1) {
	CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_MMU,
	VIVS_GL_FLUSH_MMU_FLUSH_FEMMU \|
	VIVS_GL_FLUSH_MMU_FLUSH_UNK1 \|
	VIVS_GL_FLUSH_MMU_FLUSH_UNK2 \|
	VIVS_GL_FLUSH_MMU_FLUSH_PEMMU \|
	VIVS_GL_FLUSH_MMU_FLUSH_UNK4);
	} else {
	CMD_LOAD_STATE(buffer, VIVS_MMUv2_CONFIGURATION,
	VIVS_MMUv2_CONFIGURATION_MODE_MASK \|
	VIVS_MMUv2_CONFIGURATION_ADDRESS_MASK \|
	VIVS_MMUv2_CONFIGURATION_FLUSH_FLUSH);
	CMD_SEM(buffer, SYNC_RECIPIENT_FE,
	SYNC_RECIPIENT_PE);
	CMD_STALL(buffer, SYNC_RECIPIENT_FE,
	SYNC_RECIPIENT_PE);
	}

	gpu->flush_seq = new_flush_seq;
	}

	if (switch_context) {
	etnaviv_cmd_select_pipe(gpu, buffer, exec_state);
	gpu->exec_state = exec_state;
	}

	/* And the link to the submitted buffer */
	CMD_LINK(buffer, link_dwords, link_target);

	/* Update the link target to point to above instructions */
	link_target = target;
	link_dwords = extra_dwords;
	}

	/*
	* Append a LINK to the submitted command buffer to return to
	* the ring buffer. return_target is the ring target address.
	* We need at most 7 dwords in the return target: 2 cache flush +
	* 2 semaphore stall + 1 event + 1 wait + 1 link.
	*/
	return_dwords = 7;
	return_target = etnaviv_buffer_reserve(gpu, buffer, return_dwords);
	CMD_LINK(cmdbuf, return_dwords, return_target);

	/*
	* Append a cache flush, stall, event, wait and link pointing back to
	* the wait command to the ring buffer.
	*/
	if (gpu->exec_state == ETNA_PIPE_2D) {
	CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_CACHE,
	VIVS_GL_FLUSH_CACHE_PE2D);
	} else {
	CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_CACHE,
	VIVS_GL_FLUSH_CACHE_DEPTH \|
	VIVS_GL_FLUSH_CACHE_COLOR);
	CMD_LOAD_STATE(buffer, VIVS_TS_FLUSH_CACHE,
	VIVS_TS_FLUSH_CACHE_FLUSH);
	}
	CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
	CMD_LOAD_STATE(buffer, VIVS_GL_EVENT, VIVS_GL_EVENT_EVENT_ID(event) \|
	VIVS_GL_EVENT_FROM_PE);
	CMD_WAIT(buffer);
	CMD_LINK(buffer, 2, etnaviv_cmdbuf_get_va(buffer) +
	buffer->user_size - 4);

	if (drm_debug & DRM_UT_DRIVER)
	pr_info("stream link to 0x%08x @ 0x%08x %p\n",
	return_target, etnaviv_cmdbuf_get_va(cmdbuf),
	cmdbuf->vaddr);

	if (drm_debug & DRM_UT_DRIVER) {
	print_hex_dump(KERN_INFO, "cmd ", DUMP_PREFIX_OFFSET, 16, 4,
	cmdbuf->vaddr, cmdbuf->size, 0);

	pr_info("link op: %p\n", buffer->vaddr + waitlink_offset);
	pr_info("addr: 0x%08x\n", link_target);
	pr_info("back: 0x%08x\n", return_target);
	pr_info("event: %d\n", event);
	}

	/*
	* Kick off the submitted command by replacing the previous
	* WAIT with a link to the address in the ring buffer.
	*/
	etnaviv_buffer_replace_wait(buffer, waitlink_offset,
	VIV_FE_LINK_HEADER_OP_LINK \|
	VIV_FE_LINK_HEADER_PREFETCH(link_dwords),
	link_target);

	if (drm_debug & DRM_UT_DRIVER)
	etnaviv_buffer_dump(gpu, buffer, 0, 0x50);

	gpu->lastctx = cmdbuf->ctx;
	}