savage_bci.c

底层驱动开发

/* savage_bci.c -- BCI support for Savage
 *
 * Copyright 2004  Felix Kuehling
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sub license,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NON-INFRINGEMENT. IN NO EVENT SHALL FELIX KUEHLING BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#include "drmP.h"
#include "savage_drm.h"
#include "savage_drv.h"

/* Need a long timeout for shadow status updates can take a while
 * and so can waiting for events when the queue is full. */
#define SAVAGE_DEFAULT_USEC_TIMEOUT	1000000 /* 1s */
#define SAVAGE_EVENT_USEC_TIMEOUT	5000000 /* 5s */
#define SAVAGE_FREELIST_DEBUG		0

static int
savage_bci_wait_fifo_shadow(drm_savage_private_t *dev_priv, unsigned int n)
{
	uint32_t mask = dev_priv->status_used_mask;
	uint32_t threshold = dev_priv->bci_threshold_hi;
	uint32_t status;
	int i;

#if SAVAGE_BCI_DEBUG
	if (n > dev_priv->cob_size + SAVAGE_BCI_FIFO_SIZE - threshold)
		DRM_ERROR("Trying to emit %d words "
			  "(more than guaranteed space in COB)\n", n);
#endif

	for (i = 0; i < SAVAGE_DEFAULT_USEC_TIMEOUT; i++) {
		DRM_MEMORYBARRIER();
		status = dev_priv->status_ptr[0];
		if ((status & mask) < threshold)
			return 0;
		DRM_UDELAY(1);
	}

#if SAVAGE_BCI_DEBUG
	DRM_ERROR("failed!\n");
	DRM_INFO("   status=0x%08x, threshold=0x%08x\n", status, threshold);
#endif
	return DRM_ERR(EBUSY);
}

static int
savage_bci_wait_fifo_s3d(drm_savage_private_t *dev_priv, unsigned int n)
{
	uint32_t maxUsed = dev_priv->cob_size + SAVAGE_BCI_FIFO_SIZE - n;
	uint32_t status;
	int i;

	for (i = 0; i < SAVAGE_DEFAULT_USEC_TIMEOUT; i++) {
		status = SAVAGE_READ(SAVAGE_STATUS_WORD0);
		if ((status & SAVAGE_FIFO_USED_MASK_S3D) <= maxUsed)
			return 0;
		DRM_UDELAY(1);
	}

#if SAVAGE_BCI_DEBUG
	DRM_ERROR("failed!\n");
	DRM_INFO("   status=0x%08x\n", status);
#endif
	return DRM_ERR(EBUSY);
}

static int
savage_bci_wait_fifo_s4(drm_savage_private_t *dev_priv, unsigned int n)
{
	uint32_t maxUsed = dev_priv->cob_size + SAVAGE_BCI_FIFO_SIZE - n;
	uint32_t status;
	int i;

	for (i = 0; i < SAVAGE_DEFAULT_USEC_TIMEOUT; i++) {
		status = SAVAGE_READ(SAVAGE_ALT_STATUS_WORD0);
		if ((status & SAVAGE_FIFO_USED_MASK_S4) <= maxUsed)
			return 0;
		DRM_UDELAY(1);
	}

#if SAVAGE_BCI_DEBUG
	DRM_ERROR("failed!\n");
	DRM_INFO("   status=0x%08x\n", status);
#endif
	return DRM_ERR(EBUSY);
}

/*
 * Waiting for events.
 *
 * The BIOSresets the event tag to 0 on mode changes. Therefore we
 * never emit 0 to the event tag. If we find a 0 event tag we know the
 * BIOS stomped on it and return success assuming that the BIOS waited
 * for engine idle.
 *
 * Note: if the Xserver uses the event tag it has to follow the same
 * rule. Otherwise there may be glitches every 2^16 events.
 */
static int
savage_bci_wait_event_shadow(drm_savage_private_t *dev_priv, uint16_t e)
{
	uint32_t status;
	int i;

	for (i = 0; i < SAVAGE_EVENT_USEC_TIMEOUT; i++) {
		DRM_MEMORYBARRIER();
		status = dev_priv->status_ptr[1];
		if ((((status & 0xffff) - e) & 0xffff) <= 0x7fff ||
		    (status & 0xffff) == 0)
			return 0;
		DRM_UDELAY(1);
	}

#if SAVAGE_BCI_DEBUG
	DRM_ERROR("failed!\n");
	DRM_INFO("   status=0x%08x, e=0x%04x\n", status, e);
#endif

	return DRM_ERR(EBUSY);
}

static int
savage_bci_wait_event_reg(drm_savage_private_t *dev_priv, uint16_t e)
{
	uint32_t status;
	int i;

	for (i = 0; i < SAVAGE_EVENT_USEC_TIMEOUT; i++) {
		status = SAVAGE_READ(SAVAGE_STATUS_WORD1);
		if ((((status & 0xffff) - e) & 0xffff) <= 0x7fff ||
		    (status & 0xffff) == 0)
			return 0;
		DRM_UDELAY(1);
	}

#if SAVAGE_BCI_DEBUG
	DRM_ERROR("failed!\n");
	DRM_INFO("   status=0x%08x, e=0x%04x\n", status, e);
#endif

	return DRM_ERR(EBUSY);
}

uint16_t savage_bci_emit_event(drm_savage_private_t *dev_priv,
			       unsigned int flags)
{
	uint16_t count;
	BCI_LOCALS;

	if (dev_priv->status_ptr) {
		/* coordinate with Xserver */
		count = dev_priv->status_ptr[1023];
		if (count < dev_priv->event_counter)
			dev_priv->event_wrap++;
	} else {
		count = dev_priv->event_counter;
	}
	count = (count + 1) & 0xffff;
	if (count == 0) {
		count++; /* See the comment above savage_wait_event_*. */
		dev_priv->event_wrap++;
	}
	dev_priv->event_counter = count;
	if (dev_priv->status_ptr)
		dev_priv->status_ptr[1023] = (uint32_t)count;

	if ((flags & (SAVAGE_WAIT_2D | SAVAGE_WAIT_3D))) {
		unsigned int wait_cmd = BCI_CMD_WAIT;
		if ((flags & SAVAGE_WAIT_2D))
			wait_cmd |= BCI_CMD_WAIT_2D;
		if ((flags & SAVAGE_WAIT_3D))
			wait_cmd |= BCI_CMD_WAIT_3D;
		BEGIN_BCI(2);
		BCI_WRITE(wait_cmd);
	} else {
		BEGIN_BCI(1);
	}
	BCI_WRITE(BCI_CMD_UPDATE_EVENT_TAG | (uint32_t)count);

	return count;
}

/*
 * Freelist management
 */
static int savage_freelist_init(drm_device_t *dev)
{
	drm_savage_private_t *dev_priv = dev->dev_private;
	drm_device_dma_t *dma = dev->dma;
	drm_buf_t *buf;
	drm_savage_buf_priv_t *entry;
	int i;
	DRM_DEBUG("count=%d\n", dma->buf_count);

	dev_priv->head.next = &dev_priv->tail;
	dev_priv->head.prev = NULL;
	dev_priv->head.buf = NULL;

	dev_priv->tail.next = NULL;
	dev_priv->tail.prev = &dev_priv->head;
	dev_priv->tail.buf = NULL;

	for (i = 0; i < dma->buf_count; i++) {
		buf = dma->buflist[i];
		entry = buf->dev_private;

		SET_AGE(&entry->age, 0, 0);
		entry->buf = buf;

		entry->next = dev_priv->head.next;
		entry->prev = &dev_priv->head;
		dev_priv->head.next->prev = entry;
		dev_priv->head.next = entry;
	}

	return 0;
}

static drm_buf_t *savage_freelist_get(drm_device_t *dev)
{
	drm_savage_private_t *dev_priv = dev->dev_private;
	drm_savage_buf_priv_t *tail = dev_priv->tail.prev;
	uint16_t event;
	unsigned int wrap;
	DRM_DEBUG("\n");

	UPDATE_EVENT_COUNTER();
	if (dev_priv->status_ptr)
		event = dev_priv->status_ptr[1] & 0xffff;
	else
		event = SAVAGE_READ(SAVAGE_STATUS_WORD1) & 0xffff;
	wrap = dev_priv->event_wrap;
	if (event > dev_priv->event_counter)
		wrap--; /* hardware hasn't passed the last wrap yet */

	DRM_DEBUG("   tail=0x%04x %d\n", tail->age.event, tail->age.wrap);
	DRM_DEBUG("   head=0x%04x %d\n", event, wrap);

	if (tail->buf && (TEST_AGE(&tail->age, event, wrap) || event == 0)) {
		drm_savage_buf_priv_t *next = tail->next;
		drm_savage_buf_priv_t *prev = tail->prev;
		prev->next = next;
		next->prev = prev;
		tail->next = tail->prev = NULL;
		return tail->buf;
	}

	DRM_DEBUG("returning NULL, tail->buf=%p!\n", tail->buf);
	return NULL;
}

void savage_freelist_put(drm_device_t *dev, drm_buf_t *buf)
{
	drm_savage_private_t *dev_priv = dev->dev_private;
	drm_savage_buf_priv_t *entry = buf->dev_private, *prev, *next;

	DRM_DEBUG("age=0x%04x wrap=%d\n", entry->age.event, entry->age.wrap);

	if (entry->next != NULL || entry->prev != NULL) {
		DRM_ERROR("entry already on freelist.\n");
		return;
	}

	prev = &dev_priv->head;
	next = prev->next;
	prev->next = entry;
	next->prev = entry;
	entry->prev = prev;
	entry->next = next;
}

/*
 * Command DMA
 */
static int savage_dma_init(drm_savage_private_t *dev_priv)
{
	unsigned int i;

	dev_priv->nr_dma_pages = dev_priv->cmd_dma->size /
		(SAVAGE_DMA_PAGE_SIZE*4);
	dev_priv->dma_pages = drm_alloc(sizeof(drm_savage_dma_page_t) *
					dev_priv->nr_dma_pages,
					DRM_MEM_DRIVER);
	if (dev_priv->dma_pages == NULL)
		return DRM_ERR(ENOMEM);

	for (i = 0; i < dev_priv->nr_dma_pages; ++i) {
		SET_AGE(&dev_priv->dma_pages[i].age, 0, 0);
		dev_priv->dma_pages[i].used = 0;
		dev_priv->dma_pages[i].flushed = 0;
	}
	SET_AGE(&dev_priv->last_dma_age, 0, 0);

	dev_priv->first_dma_page = 0;
	dev_priv->current_dma_page = 0;

	return 0;
}

void savage_dma_reset(drm_savage_private_t *dev_priv)
{
	uint16_t event;
	unsigned int wrap, i;
	event = savage_bci_emit_event(dev_priv, 0);
	wrap = dev_priv->event_wrap;
	for (i = 0; i < dev_priv->nr_dma_pages; ++i) {
		SET_AGE(&dev_priv->dma_pages[i].age, event, wrap);
		dev_priv->dma_pages[i].used = 0;
		dev_priv->dma_pages[i].flushed = 0;
	}
	SET_AGE(&dev_priv->last_dma_age, event, wrap);
	dev_priv->first_dma_page = dev_priv->current_dma_page = 0;
}

void savage_dma_wait(drm_savage_private_t *dev_priv, unsigned int page)
{
	uint16_t event;
	unsigned int wrap;

	/* Faked DMA buffer pages don't age. */
	if (dev_priv->cmd_dma == &dev_priv->fake_dma)
		return;

	UPDATE_EVENT_COUNTER();
	if (dev_priv->status_ptr)
		event = dev_priv->status_ptr[1] & 0xffff;
	else
		event = SAVAGE_READ(SAVAGE_STATUS_WORD1) & 0xffff;
	wrap = dev_priv->event_wrap;
	if (event > dev_priv->event_counter)
		wrap--; /* hardware hasn't passed the last wrap yet */

	if (dev_priv->dma_pages[page].age.wrap > wrap ||
	    (dev_priv->dma_pages[page].age.wrap == wrap &&
	     dev_priv->dma_pages[page].age.event > event)) {
		if (dev_priv->wait_evnt(dev_priv,
					dev_priv->dma_pages[page].age.event)
		    < 0)
			DRM_ERROR("wait_evnt failed!\n");
	}
}

uint32_t *savage_dma_alloc(drm_savage_private_t *dev_priv, unsigned int n)
{
	unsigned int cur = dev_priv->current_dma_page;
	unsigned int rest = SAVAGE_DMA_PAGE_SIZE -
		dev_priv->dma_pages[cur].used;
	unsigned int nr_pages = (n - rest + SAVAGE_DMA_PAGE_SIZE-1) /