linux/drivers/gpu/host1x/cdma.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Tegra host1x Command DMA
*
* Copyright (c) 2010-2013, NVIDIA Corporation.
*/
#include <asm/cacheflush.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/host1x.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/kfifo.h>
#include <linux/slab.h>
#include <trace/events/host1x.h>
#include "cdma.h"
#include "channel.h"
#include "dev.h"
#include "debug.h"
#include "job.h"
/*
* push_buffer
*
* The push buffer is a circular array of words to be fetched by command DMA.
* Note that it works slightly differently to the sync queue; fence == pos
* means that the push buffer is full, not empty.
*/
/*
* Typically the commands written into the push buffer are a pair of words. We
* use slots to represent each of these pairs and to simplify things. Note the
* strange number of slots allocated here. 512 slots will fit exactly within a
* single memory page. We also need one additional word at the end of the push
* buffer for the RESTART opcode that will instruct the CDMA to jump back to
* the beginning of the push buffer. With 512 slots, this means that we'll use
* 2 memory pages and waste 4092 bytes of the second page that will never be
* used.
*/
#define HOST1X_PUSHBUFFER_SLOTS 511
/*
* Clean up push buffer resources
*/
static void host1x_pushbuffer_destroy(struct push_buffer *pb)
{
struct host1x_cdma *cdma = pb_to_cdma(pb);
struct host1x *host1x = cdma_to_host1x(cdma);
if (!pb->mapped)
return;
if (host1x->domain) {
iommu_unmap(host1x->domain, pb->dma, pb->alloc_size);
free_iova(&host1x->iova, iova_pfn(&host1x->iova, pb->dma));
}
dma_free_wc(host1x->dev, pb->alloc_size, pb->mapped, pb->phys);
pb->mapped = NULL;
pb->phys = 0;
}
/*
* Init push buffer resources
*/
static int host1x_pushbuffer_init(struct push_buffer *pb)
{
struct host1x_cdma *cdma = pb_to_cdma(pb);
struct host1x *host1x = cdma_to_host1x(cdma);
struct iova *alloc;
u32 size;
int err;
pb->mapped = NULL;
pb->phys = 0;
pb->size = HOST1X_PUSHBUFFER_SLOTS * 8;
size = pb->size + 4;
/* initialize buffer pointers */
pb->fence = pb->size - 8;
pb->pos = 0;
if (host1x->domain) {
unsigned long shift;
size = iova_align(&host1x->iova, size);
pb->mapped = dma_alloc_wc(host1x->dev, size, &pb->phys,
GFP_KERNEL);
if (!pb->mapped)
return -ENOMEM;
shift = iova_shift(&host1x->iova);
alloc = alloc_iova(&host1x->iova, size >> shift,
host1x->iova_end >> shift, true);
if (!alloc) {
err = -ENOMEM;
goto iommu_free_mem;
}
pb->dma = iova_dma_addr(&host1x->iova, alloc);
err = iommu_map(host1x->domain, pb->dma, pb->phys, size,
IOMMU_READ);
if (err)
goto iommu_free_iova;
} else {
pb->mapped = dma_alloc_wc(host1x->dev, size, &pb->phys,
GFP_KERNEL);
if (!pb->mapped)
return -ENOMEM;
pb->dma = pb->phys;
}
pb->alloc_size = size;
host1x_hw_pushbuffer_init(host1x, pb);
return 0;
iommu_free_iova:
__free_iova(&host1x->iova, alloc);
iommu_free_mem:
dma_free_wc(host1x->dev, size, pb->mapped, pb->phys);
return err;
}
/*
* Push two words to the push buffer
* Caller must ensure push buffer is not full
*/
static void host1x_pushbuffer_push(struct push_buffer *pb, u32 op1, u32 op2)
{
u32 *p = (u32 *)((void *)pb->mapped + pb->pos);
WARN_ON(pb->pos == pb->fence);
*(p++) = op1;
*(p++) = op2;
pb->pos += 8;
if (pb->pos >= pb->size)
pb->pos -= pb->size;
}
/*
* Pop a number of two word slots from the push buffer
* Caller must ensure push buffer is not empty
*/
static void host1x_pushbuffer_pop(struct push_buffer *pb, unsigned int slots)
{
/* Advance the next write position */
pb->fence += slots * 8;
if (pb->fence >= pb->size)
pb->fence -= pb->size;
}
/*
* Return the number of two word slots free in the push buffer
*/
static u32 host1x_pushbuffer_space(struct push_buffer *pb)
{
unsigned int fence = pb->fence;
if (pb->fence < pb->pos)
fence += pb->size;
return (fence - pb->pos) / 8;
}
/*
* Sleep (if necessary) until the requested event happens
* - CDMA_EVENT_SYNC_QUEUE_EMPTY : sync queue is completely empty.
* - Returns 1
* - CDMA_EVENT_PUSH_BUFFER_SPACE : there is space in the push buffer
* - Return the amount of space (> 0)
* Must be called with the cdma lock held.
*/
unsigned int host1x_cdma_wait_locked(struct host1x_cdma *cdma,
enum cdma_event event)
{
for (;;) {
struct push_buffer *pb = &cdma->push_buffer;
unsigned int space;
switch (event) {
case CDMA_EVENT_SYNC_QUEUE_EMPTY:
space = list_empty(&cdma->sync_queue) ? 1 : 0;
break;
case CDMA_EVENT_PUSH_BUFFER_SPACE:
space = host1x_pushbuffer_space(pb);
break;
default:
WARN_ON(1);
return -EINVAL;
}
if (space)
return space;
trace_host1x_wait_cdma(dev_name(cdma_to_channel(cdma)->dev),
event);
/* If somebody has managed to already start waiting, yield */
if (cdma->event != CDMA_EVENT_NONE) {
mutex_unlock(&cdma->lock);
schedule();
mutex_lock(&cdma->lock);
continue;
}
cdma->event = event;
mutex_unlock(&cdma->lock);
wait_for_completion(&cdma->complete);
mutex_lock(&cdma->lock);
}
return 0;
}
/*
* Sleep (if necessary) until the push buffer has enough free space.
*
* Must be called with the cdma lock held.
*/
static int host1x_cdma_wait_pushbuffer_space(struct host1x *host1x,
struct host1x_cdma *cdma,
unsigned int needed)
{
while (true) {
struct push_buffer *pb = &cdma->push_buffer;
unsigned int space;
space = host1x_pushbuffer_space(pb);
if (space >= needed)
break;
trace_host1x_wait_cdma(dev_name(cdma_to_channel(cdma)->dev),
CDMA_EVENT_PUSH_BUFFER_SPACE);
host1x_hw_cdma_flush(host1x, cdma);
/* If somebody has managed to already start waiting, yield */
if (cdma->event != CDMA_EVENT_NONE) {
mutex_unlock(&cdma->lock);
schedule();
mutex_lock(&cdma->lock);
continue;
}
cdma->event = CDMA_EVENT_PUSH_BUFFER_SPACE;
mutex_unlock(&cdma->lock);
wait_for_completion(&cdma->complete);
mutex_lock(&cdma->lock);
}
return 0;
}
/*
* Start timer that tracks the time spent by the job.
* Must be called with the cdma lock held.
*/
static void cdma_start_timer_locked(struct host1x_cdma *cdma,
struct host1x_job *job)
{
struct host1x *host = cdma_to_host1x(cdma);
if (cdma->timeout.client) {
/* timer already started */
return;
}
cdma->timeout.client = job->client;
cdma->timeout.syncpt = host1x_syncpt_get(host, job->syncpt_id);
cdma->timeout.syncpt_val = job->syncpt_end;
cdma->timeout.start_ktime = ktime_get();
schedule_delayed_work(&cdma->timeout.wq,
msecs_to_jiffies(job->timeout));
}
/*
* Stop timer when a buffer submission completes.
* Must be called with the cdma lock held.
*/
static void stop_cdma_timer_locked(struct host1x_cdma *cdma)
{
cancel_delayed_work(&cdma->timeout.wq);
cdma->timeout.client = NULL;
}
/*
* For all sync queue entries that have already finished according to the
* current sync point registers:
* - unpin & unref their mems
* - pop their push buffer slots
* - remove them from the sync queue
* This is normally called from the host code's worker thread, but can be
* called manually if necessary.
* Must be called with the cdma lock held.
*/
static void update_cdma_locked(struct host1x_cdma *cdma)
{
bool signal = false;
struct host1x *host1x = cdma_to_host1x(cdma);
struct host1x_job *job, *n;
/* If CDMA is stopped, queue is cleared and we can return */
if (!cdma->running)
return;
/*
* Walk the sync queue, reading the sync point registers as necessary,
* to consume as many sync queue entries as possible without blocking
*/
list_for_each_entry_safe(job, n, &cdma->sync_queue, list) {
struct host1x_syncpt *sp =
host1x_syncpt_get(host1x, job->syncpt_id);
/* Check whether this syncpt has completed, and bail if not */
if (!host1x_syncpt_is_expired(sp, job->syncpt_end)) {
/* Start timer on next pending syncpt */
if (job->timeout)
cdma_start_timer_locked(cdma, job);
break;
}
/* Cancel timeout, when a buffer completes */
if (cdma->timeout.client)
stop_cdma_timer_locked(cdma);
/* Unpin the memory */
host1x_job_unpin(job);
/* Pop push buffer slots */
if (job->num_slots) {
struct push_buffer *pb = &cdma->push_buffer;
host1x_pushbuffer_pop(pb, job->num_slots);
if (cdma->event == CDMA_EVENT_PUSH_BUFFER_SPACE)
signal = true;
}
list_del(&job->list);
host1x_job_put(job);
}
if (cdma->event == CDMA_EVENT_SYNC_QUEUE_EMPTY &&
list_empty(&cdma->sync_queue))
signal = true;
if (signal) {
cdma->event = CDMA_EVENT_NONE;
complete(&cdma->complete);
}
}
void host1x_cdma_update_sync_queue(struct host1x_cdma *cdma,
struct device *dev)
{
struct host1x *host1x = cdma_to_host1x(cdma);
u32 restart_addr, syncpt_incrs, syncpt_val;
struct host1x_job *job, *next_job = NULL;
syncpt_val = host1x_syncpt_load(cdma->timeout.syncpt);
dev_dbg(dev, "%s: starting cleanup (thresh %d)\n",
__func__, syncpt_val);
/*
* Move the sync_queue read pointer to the first entry that hasn't
* completed based on the current HW syncpt value. It's likely there
* won't be any (i.e. we're still at the head), but covers the case
* where a syncpt incr happens just prior/during the teardown.
*/
dev_dbg(dev, "%s: skip completed buffers still in sync_queue\n",
__func__);
list_for_each_entry(job, &cdma->sync_queue, list) {
if (syncpt_val < job->syncpt_end) {
if (!list_is_last(&job->list, &cdma->sync_queue))
next_job = list_next_entry(job, list);
goto syncpt_incr;
}
host1x_job_dump(dev, job);
}
/* all jobs have been completed */
job = NULL;
syncpt_incr:
/*
* Increment with CPU the remaining syncpts of a partially executed job.
*
* CDMA will continue execution starting with the next job or will get
* into idle state.
*/
if (next_job)
restart_addr = next_job->first_get;
else
restart_addr = cdma->last_pos;
/* do CPU increments for the remaining syncpts */
if (job) {
dev_dbg(dev, "%s: perform CPU incr on pending buffers\n",
__func__);
/* won't need a timeout when replayed */
job->timeout = 0;
syncpt_incrs = job->syncpt_end - syncpt_val;
dev_dbg(dev, "%s: CPU incr (%d)\n", __func__, syncpt_incrs);
host1x_job_dump(dev, job);
/* safe to use CPU to incr syncpts */
host1x_hw_cdma_timeout_cpu_incr(host1x, cdma, job->first_get,
syncpt_incrs, job->syncpt_end,
job->num_slots);
dev_dbg(dev, "%s: finished sync_queue modification\n",
__func__);
}
/* roll back DMAGET and start up channel again */
host1x_hw_cdma_resume(host1x, cdma, restart_addr);
}
/*
* Create a cdma
*/
int host1x_cdma_init(struct host1x_cdma *cdma)
{
int err;
mutex_init(&cdma->lock);
init_completion(&cdma->complete);
INIT_LIST_HEAD(&cdma->sync_queue);
cdma->event = CDMA_EVENT_NONE;
cdma->running = false;
cdma->torndown = false;
err = host1x_pushbuffer_init(&cdma->push_buffer);
if (err)
return err;
return 0;
}
/*
* Destroy a cdma
*/
int host1x_cdma_deinit(struct host1x_cdma *cdma)
{
struct push_buffer *pb = &cdma->push_buffer;
struct host1x *host1x = cdma_to_host1x(cdma);
if (cdma->running) {
pr_warn("%s: CDMA still running\n", __func__);
return -EBUSY;
}
host1x_pushbuffer_destroy(pb);
host1x_hw_cdma_timeout_destroy(host1x, cdma);
return 0;
}
/*
* Begin a cdma submit
*/
int host1x_cdma_begin(struct host1x_cdma *cdma, struct host1x_job *job)
{
struct host1x *host1x = cdma_to_host1x(cdma);
mutex_lock(&cdma->lock);
if (job->timeout) {
/* init state on first submit with timeout value */
if (!cdma->timeout.initialized) {
int err;
err = host1x_hw_cdma_timeout_init(host1x, cdma,
job->syncpt_id);
if (err) {
mutex_unlock(&cdma->lock);
return err;
}
}
}
if (!cdma->running)
host1x_hw_cdma_start(host1x, cdma);
cdma->slots_free = 0;
cdma->slots_used = 0;
cdma->first_get = cdma->push_buffer.pos;
trace_host1x_cdma_begin(dev_name(job->channel->dev));
return 0;
}
/*
* Push two words into a push buffer slot
* Blocks as necessary if the push buffer is full.
*/
void host1x_cdma_push(struct host1x_cdma *cdma, u32 op1, u32 op2)
{
struct host1x *host1x = cdma_to_host1x(cdma);
struct push_buffer *pb = &cdma->push_buffer;
u32 slots_free = cdma->slots_free;
if (host1x_debug_trace_cmdbuf)
trace_host1x_cdma_push(dev_name(cdma_to_channel(cdma)->dev),
op1, op2);
if (slots_free == 0) {
host1x_hw_cdma_flush(host1x, cdma);
slots_free = host1x_cdma_wait_locked(cdma,
CDMA_EVENT_PUSH_BUFFER_SPACE);
}
cdma->slots_free = slots_free - 1;
cdma->slots_used++;
host1x_pushbuffer_push(pb, op1, op2);
}
/*
* Push four words into two consecutive push buffer slots. Note that extra
* care needs to be taken not to split the two slots across the end of the
* push buffer. Otherwise the RESTART opcode at the end of the push buffer
* that ensures processing will restart at the beginning will break up the
* four words.
*
* Blocks as necessary if the push buffer is full.
*/
void host1x_cdma_push_wide(struct host1x_cdma *cdma, u32 op1, u32 op2,
u32 op3, u32 op4)
{
struct host1x_channel *channel = cdma_to_channel(cdma);
struct host1x *host1x = cdma_to_host1x(cdma);
struct push_buffer *pb = &cdma->push_buffer;
unsigned int needed = 2, extra = 0, i;
unsigned int space = cdma->slots_free;
if (host1x_debug_trace_cmdbuf)
trace_host1x_cdma_push_wide(dev_name(channel->dev), op1, op2,
op3, op4);
/* compute number of extra slots needed for padding */
if (pb->pos + 16 > pb->size) {
extra = (pb->size - pb->pos) / 8;
needed += extra;
}
host1x_cdma_wait_pushbuffer_space(host1x, cdma, needed);
space = host1x_pushbuffer_space(pb);
cdma->slots_free = space - needed;
cdma->slots_used += needed;
/*
* Note that we rely on the fact that this is only used to submit wide
* gather opcodes, which consist of 3 words, and they are padded with
* a NOP to avoid having to deal with fractional slots (a slot always
* represents 2 words). The fourth opcode passed to this function will
* therefore always be a NOP.
*
* This works around a slight ambiguity when it comes to opcodes. For
* all current host1x incarnations the NOP opcode uses the exact same
* encoding (0x20000000), so we could hard-code the value here, but a
* new incarnation may change it and break that assumption.
*/
for (i = 0; i < extra; i++)
host1x_pushbuffer_push(pb, op4, op4);
host1x_pushbuffer_push(pb, op1, op2);
host1x_pushbuffer_push(pb, op3, op4);
}
/*
* End a cdma submit
* Kick off DMA, add job to the sync queue, and a number of slots to be freed
* from the pushbuffer. The handles for a submit must all be pinned at the same
* time, but they can be unpinned in smaller chunks.
*/
void host1x_cdma_end(struct host1x_cdma *cdma,
struct host1x_job *job)
{
struct host1x *host1x = cdma_to_host1x(cdma);
bool idle = list_empty(&cdma->sync_queue);
host1x_hw_cdma_flush(host1x, cdma);
job->first_get = cdma->first_get;
job->num_slots = cdma->slots_used;
host1x_job_get(job);
list_add_tail(&job->list, &cdma->sync_queue);
/* start timer on idle -> active transitions */
if (job->timeout && idle)
cdma_start_timer_locked(cdma, job);
trace_host1x_cdma_end(dev_name(job->channel->dev));
mutex_unlock(&cdma->lock);
}
/*
* Update cdma state according to current sync point values
*/
void host1x_cdma_update(struct host1x_cdma *cdma)
{
mutex_lock(&cdma->lock);
update_cdma_locked(cdma);
mutex_unlock(&cdma->lock);
}