gma500: introduce the GTT and MMU handling logic

/*

 * Copyright (c) 2007, Intel Corporation.

 * All Rights Reserved.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program; if not, write to the Free Software Foundation, Inc.,

 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Authors: Thomas Hellstrom <thomas-at-tungstengraphics.com>

 *	    Alan Cox <alan@linux.intel.com>

 */

#include <drm/drmP.h>

#include "psb_drv.h"

/*

 *	GTT resource allocator - manage page mappings in GTT space

 */

/**

 *	psb_gtt_mask_pte	-	generate GTT pte entry

 *	@pfn: page number to encode

 *	@type: type of memory in the GTT

 *

 *	Set the GTT entry for the appropriate memory type.

 */

static inline uint32_t psb_gtt_mask_pte(uint32_t pfn, int type)

{

	uint32_t mask = PSB_PTE_VALID;

	if (type & PSB_MMU_CACHED_MEMORY)

		mask |= PSB_PTE_CACHED;

	if (type & PSB_MMU_RO_MEMORY)

		mask |= PSB_PTE_RO;

	if (type & PSB_MMU_WO_MEMORY)

		mask |= PSB_PTE_WO;

	return (pfn << PAGE_SHIFT) | mask;

}

/**

 *	psb_gtt_entry		-	find the GTT entries for a gtt_range

 *	@dev: our DRM device

 *	@r: our GTT range

 *

 *	Given a gtt_range object return the GTT offset of the page table

 *	entries for this gtt_range

 */

u32 *psb_gtt_entry(struct drm_device *dev, struct gtt_range *r)

{

	struct drm_psb_private *dev_priv = dev->dev_private;

	unsigned long offset;

	offset = r->resource.start - dev_priv->gtt_mem->start;

	return dev_priv->gtt_map + (offset >> PAGE_SHIFT);

}

/**

 *	psb_gtt_insert	-	put an object into the GTT

 *	@dev: our DRM device

 *	@r: our GTT range

 *

 *	Take our preallocated GTT range and insert the GEM object into

 *	the GTT.

 *

 *	FIXME: gtt lock ?

 */

static int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r)

{

	u32 *gtt_slot, pte;

	struct page **pages;

	int i;

	if (r->pages == NULL) {

		WARN_ON(1);

		return -EINVAL;

	}

	WARN_ON(r->stolen);	/* refcount these maybe ? */

	gtt_slot = psb_gtt_entry(dev, r);

	pages = r->pages;

	/* Make sure changes are visible to the GPU */

	set_pages_array_uc(pages, r->npage);

	/* Write our page entries into the GTT itself */

	for (i = 0; i < r->npage; i++) {

		pte = psb_gtt_mask_pte(page_to_pfn(*pages++), 0/*type*/);

		iowrite32(pte, gtt_slot++);

	}

	/* Make sure all the entries are set before we return */

	ioread32(gtt_slot - 1);

	return 0;

}

/**

 *	psb_gtt_remove	-	remove an object from the GTT

 *	@dev: our DRM device

 *	@r: our GTT range

 *

 *	Remove a preallocated GTT range from the GTT. Overwrite all the

 *	page table entries with the dummy page

 */

static void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r)

{

	struct drm_psb_private *dev_priv = dev->dev_private;

	u32 *gtt_slot, pte;

	int i;

	WARN_ON(r->stolen);

	gtt_slot = psb_gtt_entry(dev, r);

	pte = psb_gtt_mask_pte(page_to_pfn(dev_priv->scratch_page), 0);

	for (i = 0; i < r->npage; i++)

		iowrite32(pte, gtt_slot++);

	ioread32(gtt_slot - 1);

	set_pages_array_wb(r->pages, r->npage);

}

/**

 *	psb_gtt_attach_pages	-	attach and pin GEM pages

 *	@gt: the gtt range

 *

 *	Pin and build an in kernel list of the pages that back our GEM object.

 *	While we hold this the pages cannot be swapped out

 */

static int psb_gtt_attach_pages(struct gtt_range *gt)

{

	struct inode *inode;

	struct address_space *mapping;

	int i;

	struct page *p;

	int pages = gt->gem.size / PAGE_SIZE;

	WARN_ON(gt->pages);

	/* This is the shared memory object that backs the GEM resource */

	inode = gt->gem.filp->f_path.dentry->d_inode;

	mapping = inode->i_mapping;

	gt->pages = kmalloc(pages * sizeof(struct page *), GFP_KERNEL);

	if (gt->pages == NULL)

		return -ENOMEM;

	gt->npage = pages;

	for (i = 0; i < pages; i++) {

		/* FIXME: review flags later */

		p = read_cache_page_gfp(mapping, i,

					__GFP_COLD | GFP_KERNEL);

		if (IS_ERR(p))

			goto err;

		gt->pages[i] = p;

	}

	return 0;

err:

	while (i--)

		page_cache_release(gt->pages[i]);

	kfree(gt->pages);

	gt->pages = NULL;

	return PTR_ERR(p);

}

/**

 *	psb_gtt_detach_pages	-	attach and pin GEM pages

 *	@gt: the gtt range

 *

 *	Undo the effect of psb_gtt_attach_pages. At this point the pages

 *	must have been removed from the GTT as they could now be paged out

 *	and move bus address.

 */

static void psb_gtt_detach_pages(struct gtt_range *gt)

{

	int i;

	for (i = 0; i < gt->npage; i++) {

		/* FIXME: do we need to force dirty */

		set_page_dirty(gt->pages[i]);

		page_cache_release(gt->pages[i]);

	}

	kfree(gt->pages);

	gt->pages = NULL;

}

/**

 *	psb_gtt_pin		-	pin pages into the GTT

 *	@gt: range to pin

 *

 *	Pin a set of pages into the GTT. The pins are refcounted so that

 *	multiple pins need multiple unpins to undo.

 *

 *	Non GEM backed objects treat this as a no-op as they are always GTT

 *	backed objects.

 */

int psb_gtt_pin(struct gtt_range *gt)

{

	int ret = 0;

	struct drm_device *dev = gt->gem.dev;

	struct drm_psb_private *dev_priv = dev->dev_private;

	mutex_lock(&dev_priv->gtt_mutex);

	if (gt->in_gart == 0 && gt->stolen == 0) {

		ret = psb_gtt_attach_pages(gt);

		if (ret < 0)

			goto out;

		ret = psb_gtt_insert(dev, gt);

		if (ret < 0) {

			psb_gtt_detach_pages(gt);

			goto out;

		}

	}

	gt->in_gart++;

out:

	mutex_unlock(&dev_priv->gtt_mutex);

	return ret;

}

/**

 *	psb_gtt_unpin		-	Drop a GTT pin requirement

 *	@gt: range to pin

 *

 *	Undoes the effect of psb_gtt_pin. On the last drop the GEM object

 *	will be removed from the GTT which will also drop the page references

 *	and allow the VM to clean up or page stuff.

 *

 *	Non GEM backed objects treat this as a no-op as they are always GTT

 *	backed objects.

 */

void psb_gtt_unpin(struct gtt_range *gt)

{

	struct drm_device *dev = gt->gem.dev;

	struct drm_psb_private *dev_priv = dev->dev_private;

	mutex_lock(&dev_priv->gtt_mutex);

	WARN_ON(!gt->in_gart);

	gt->in_gart--;

	if (gt->in_gart == 0 && gt->stolen == 0) {

		psb_gtt_remove(dev, gt);

		psb_gtt_detach_pages(gt);

	}

	mutex_unlock(&dev_priv->gtt_mutex);

}

/*

 *	GTT resource allocator - allocate and manage GTT address space

 */

/**

 *	psb_gtt_alloc_range	-	allocate GTT address space

 *	@dev: Our DRM device

 *	@len: length (bytes) of address space required

 *	@name: resource name

 *	@backed: resource should be backed by stolen pages

 *

 *	Ask the kernel core to find us a suitable range of addresses

 *	to use for a GTT mapping.

 *

 *	Returns a gtt_range structure describing the object, or NULL on

 *	error. On successful return the resource is both allocated and marked

 *	as in use.

 */

struct gtt_range *psb_gtt_alloc_range(struct drm_device *dev, int len,

						const char *name, int backed)

{

	struct drm_psb_private *dev_priv = dev->dev_private;

	struct gtt_range *gt;

	struct resource *r = dev_priv->gtt_mem;

	int ret;

	unsigned long start, end;

	if (backed) {

		/* The start of the GTT is the stolen pages */

		start = r->start;

		end = r->start + dev_priv->gtt.stolen_size - 1;

	} else {

		/* The rest we will use for GEM backed objects */

		start = r->start + dev_priv->gtt.stolen_size;

		end = r->end;

	}

	gt = kzalloc(sizeof(struct gtt_range), GFP_KERNEL);

	if (gt == NULL)

		return NULL;

	gt->resource.name = name;

	gt->stolen = backed;

	gt->in_gart = backed;

	/* Ensure this is set for non GEM objects */

	gt->gem.dev = dev;

	ret = allocate_resource(dev_priv->gtt_mem, &gt->resource,

				len, start, end, PAGE_SIZE, NULL, NULL);

	if (ret == 0) {

		gt->offset = gt->resource.start - r->start;

		return gt;

	}

	kfree(gt);

	return NULL;

}

/**

 *	psb_gtt_free_range	-	release GTT address space

 *	@dev: our DRM device

 *	@gt: a mapping created with psb_gtt_alloc_range

 *

 *	Release a resource that was allocated with psb_gtt_alloc_range. If the

 *	object has been pinned by mmap users we clean this up here currently.

 */

void psb_gtt_free_range(struct drm_device *dev, struct gtt_range *gt)

{

	/* Undo the mmap pin if we are destroying the object */

	if (gt->mmapping) {

		psb_gtt_unpin(gt);

		gt->mmapping = 0;

	}

	WARN_ON(gt->in_gart && !gt->stolen);

	release_resource(&gt->resource);

	kfree(gt);

}

void psb_gtt_alloc(struct drm_device *dev)

{

	struct drm_psb_private *dev_priv = dev->dev_private;

	init_rwsem(&dev_priv->gtt.sem);

}

void psb_gtt_takedown(struct drm_device *dev)

{

	struct drm_psb_private *dev_priv = dev->dev_private;

	if (dev_priv->gtt_map) {

		iounmap(dev_priv->gtt_map);

		dev_priv->gtt_map = NULL;

	}

	if (dev_priv->gtt_initialized) {

		pci_write_config_word(dev->pdev, PSB_GMCH_CTRL,

				      dev_priv->gmch_ctrl);

		PSB_WVDC32(dev_priv->pge_ctl, PSB_PGETBL_CTL);

		(void) PSB_RVDC32(PSB_PGETBL_CTL);

	}

	if (dev_priv->vram_addr)

		iounmap(dev_priv->gtt_map);

}

int psb_gtt_init(struct drm_device *dev, int resume)

{

	struct drm_psb_private *dev_priv = dev->dev_private;

	unsigned gtt_pages;

	unsigned long stolen_size, vram_stolen_size;

	unsigned i, num_pages;

	unsigned pfn_base;

	uint32_t vram_pages;

	uint32_t dvmt_mode = 0;

	struct psb_gtt *pg;

	int ret = 0;

	uint32_t pte;

	mutex_init(&dev_priv->gtt_mutex);

	psb_gtt_alloc(dev);

	pg = &dev_priv->gtt;

	/* Enable the GTT */

	pci_read_config_word(dev->pdev, PSB_GMCH_CTRL, &dev_priv->gmch_ctrl);

	pci_write_config_word(dev->pdev, PSB_GMCH_CTRL,

			      dev_priv->gmch_ctrl | _PSB_GMCH_ENABLED);

	dev_priv->pge_ctl = PSB_RVDC32(PSB_PGETBL_CTL);

	PSB_WVDC32(dev_priv->pge_ctl | _PSB_PGETBL_ENABLED, PSB_PGETBL_CTL);

	(void) PSB_RVDC32(PSB_PGETBL_CTL);

	/* The root resource we allocate address space from */

	dev_priv->gtt_initialized = 1;

	pg->gtt_phys_start = dev_priv->pge_ctl & PAGE_MASK;

	/*

	 *	FIXME: video mmu has hw bug to access 0x0D0000000,

	 *	then make gatt start at 0x0e000,0000

	 */

	pg->mmu_gatt_start = 0xE0000000;

	pg->gtt_start = pci_resource_start(dev->pdev, PSB_GTT_RESOURCE);

	gtt_pages = pci_resource_len(dev->pdev, PSB_GTT_RESOURCE)

								>> PAGE_SHIFT;

	/* CDV workaround */

	if (pg->gtt_start == 0 || gtt_pages == 0) {

		dev_err(dev->dev, "GTT PCI BAR not initialized.\n");

		gtt_pages = 64;

		pg->gtt_start = dev_priv->pge_ctl;

	}

	pg->gatt_start = pci_resource_start(dev->pdev, PSB_GATT_RESOURCE);

	pg->gatt_pages = pci_resource_len(dev->pdev, PSB_GATT_RESOURCE)

								>> PAGE_SHIFT;

	dev_priv->gtt_mem = &dev->pdev->resource[PSB_GATT_RESOURCE];

	if (pg->gatt_pages == 0 || pg->gatt_start == 0) {

		static struct resource fudge;	/* Preferably peppermint */

		/* This can occur on CDV SDV systems. Fudge it in this case.

		   We really don't care what imaginary space is being allocated

		   at this point */

		dev_err(dev->dev, "GATT PCI BAR not initialized.\n");

		pg->gatt_start = 0x40000000;

		pg->gatt_pages = (128 * 1024 * 1024) >> PAGE_SHIFT;

		fudge.start = 0x40000000;

		fudge.end = 0x40000000 + 128 * 1024 * 1024 - 1;

		fudge.name = "fudge";

		fudge.flags = IORESOURCE_MEM;

		dev_priv->gtt_mem = &fudge;

	}

	pci_read_config_dword(dev->pdev, PSB_BSM, &dev_priv->stolen_base);

	vram_stolen_size = pg->gtt_phys_start - dev_priv->stolen_base

								- PAGE_SIZE;

	stolen_size = vram_stolen_size;

	printk(KERN_INFO "Stolen memory information\n");

	printk(KERN_INFO "       base in RAM: 0x%x\n", dev_priv->stolen_base);

	printk(KERN_INFO "       size: %luK, calculated by (GTT RAM base) - (Stolen base), seems wrong\n",

		vram_stolen_size/1024);

	dvmt_mode = (dev_priv->gmch_ctrl >> 4) & 0x7;

	printk(KERN_INFO "      the correct size should be: %dM(dvmt mode=%d)\n",

		(dvmt_mode == 1) ? 1 : (2 << (dvmt_mode - 1)), dvmt_mode);

	if (resume && (gtt_pages != pg->gtt_pages) &&

	    (stolen_size != pg->stolen_size)) {

		dev_err(dev->dev, "GTT resume error.\n");

		ret = -EINVAL;

		goto out_err;

	}

	pg->gtt_pages = gtt_pages;

	pg->stolen_size = stolen_size;

	dev_priv->vram_stolen_size = vram_stolen_size;

	/*

	 *	Map the GTT and the stolen memory area

	 */

	dev_priv->gtt_map = ioremap_nocache(pg->gtt_phys_start,

						gtt_pages << PAGE_SHIFT);

	if (!dev_priv->gtt_map) {

		dev_err(dev->dev, "Failure to map gtt.\n");

		ret = -ENOMEM;

		goto out_err;

	}

	dev_priv->vram_addr = ioremap_wc(dev_priv->stolen_base, stolen_size);

	if (!dev_priv->vram_addr) {

		dev_err(dev->dev, "Failure to map stolen base.\n");

		ret = -ENOMEM;

		goto out_err;

	}

	/*

	 * Insert vram stolen pages into the GTT

	 */

	pfn_base = dev_priv->stolen_base >> PAGE_SHIFT;

	vram_pages = num_pages = vram_stolen_size >> PAGE_SHIFT;

	printk(KERN_INFO"Set up %d stolen pages starting at 0x%08x, GTT offset %dK\n",

		num_pages, pfn_base << PAGE_SHIFT, 0);

	for (i = 0; i < num_pages; ++i) {

		pte = psb_gtt_mask_pte(pfn_base + i, 0);

		iowrite32(pte, dev_priv->gtt_map + i);

	}

	/*

	 * Init rest of GTT to the scratch page to avoid accidents or scribbles

	 */

	pfn_base = page_to_pfn(dev_priv->scratch_page);

	pte = psb_gtt_mask_pte(pfn_base, 0);

	for (; i < gtt_pages; ++i)

		iowrite32(pte, dev_priv->gtt_map + i);

	(void) ioread32(dev_priv->gtt_map + i - 1);

	return 0;

out_err:

	psb_gtt_takedown(dev);

	return ret;

}

/**************************************************************************

 * Copyright (c) 2007-2008, Intel Corporation.

 * All Rights Reserved.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program; if not, write to the Free Software Foundation, Inc.,

 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

 *

 **************************************************************************/

#ifndef _PSB_GTT_H_

#define _PSB_GTT_H_

#include <drm/drmP.h>

/* This wants cleaning up with respect to the psb_dev and un-needed stuff */

struct psb_gtt {

	uint32_t gatt_start;

	uint32_t mmu_gatt_start;

	uint32_t gtt_start;

	uint32_t gtt_phys_start;

	unsigned gtt_pages;

	unsigned gatt_pages;

	unsigned long stolen_size;

	unsigned long vram_stolen_size;

	struct rw_semaphore sem;

};

/* Exported functions */

extern int psb_gtt_init(struct drm_device *dev, int resume);

extern void psb_gtt_takedown(struct drm_device *dev);

/* Each gtt_range describes an allocation in the GTT area */

struct gtt_range {

	struct resource resource;	/* Resource for our allocation */

	u32 offset;			/* GTT offset of our object */

	struct drm_gem_object gem;	/* GEM high level stuff */

	int in_gart;			/* Currently in the GART (ref ct) */

	bool stolen;			/* Backed from stolen RAM */

	bool mmapping;			/* Is mmappable */

	struct page **pages;		/* Backing pages if present */

	int npage;			/* Number of backing pages */

};

extern struct gtt_range *psb_gtt_alloc_range(struct drm_device *dev, int len,

						const char *name, int backed);

extern void psb_gtt_kref_put(struct gtt_range *gt);

extern void psb_gtt_free_range(struct drm_device *dev, struct gtt_range *gt);

extern int psb_gtt_pin(struct gtt_range *gt);

extern void psb_gtt_unpin(struct gtt_range *gt);

#endif