/*
 * Copyright (c) 2017-2018, NVIDIA 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, see <http://www.gnu.org/licenses/>.
 */

#include <linux/dma-mapping.h>
#include <linux/version.h>

#include <nvgpu/log.h>
#include <nvgpu/dma.h>
#include <nvgpu/lock.h>
#include <nvgpu/bug.h>
#include <nvgpu/gmmu.h>
#include <nvgpu/kmem.h>
#include <nvgpu/enabled.h>
#include <nvgpu/vidmem.h>
#include <nvgpu/gk20a.h>

#include <nvgpu/linux/dma.h>

#include "platform_gk20a.h"
#include "os_linux.h"
#include "dmabuf_vidmem.h"

#ifdef __DMA_ATTRS_LONGS
#define NVGPU_DEFINE_DMA_ATTRS(x)                                     \
        struct dma_attrs x = {                                  \
                .flags = { [0 ... __DMA_ATTRS_LONGS-1] = 0 },   \
        }
#define NVGPU_DMA_ATTR(attrs) &attrs
#else
#define NVGPU_DEFINE_DMA_ATTRS(attrs) unsigned long attrs = 0
#define NVGPU_DMA_ATTR(attrs) attrs
#endif

/*
 * Enough to hold all the possible flags in string form. When a new flag is
 * added it must be added here as well!!
 */
#define NVGPU_DMA_STR_SIZE					\
	sizeof("NO_KERNEL_MAPPING FORCE_CONTIGUOUS")

/*
 * The returned string is kmalloc()ed here but must be freed by the caller.
 */
static char *nvgpu_dma_flags_to_str(struct gk20a *g, unsigned long flags)
{
	char *buf = nvgpu_kzalloc(g, NVGPU_DMA_STR_SIZE);
	int bytes_available = NVGPU_DMA_STR_SIZE;

	/*
	 * Return the empty buffer if there's no flags. Makes it easier on the
	 * calling code to just print it instead of any if (NULL) type logic.
	 */
	if (!flags)
		return buf;

#define APPEND_FLAG(flag, str_flag)					\
	do {								\
		if (flags & flag) {					\
			strncat(buf, str_flag, bytes_available);	\
			bytes_available -= strlen(str_flag);		\
		}							\
	} while (0)

	APPEND_FLAG(NVGPU_DMA_NO_KERNEL_MAPPING, "NO_KERNEL_MAPPING ");
	APPEND_FLAG(NVGPU_DMA_FORCE_CONTIGUOUS,  "FORCE_CONTIGUOUS ");
#undef APPEND_FLAG

	return buf;
}

/**
 * __dma_dbg - Debug print for DMA allocs and frees.
 *
 * @g     - The GPU.
 * @size  - The requested size of the alloc (size_t).
 * @flags - The flags (unsigned long).
 * @type  - A string describing the type (i.e: sysmem or vidmem).
 * @what  - A string with 'alloc' or 'free'.
 *
 * @flags is the DMA flags. If there are none or it doesn't make sense to print
 * flags just pass 0.
 *
 * Please use dma_dbg_alloc() and dma_dbg_free() instead of this function.
 */
static void __dma_dbg(struct gk20a *g, size_t size, unsigned long flags,
		      const char *type, const char *what,
		      const char *func, int line)
{
	char *flags_str = NULL;

	/*
	 * Don't bother making the flags_str if debugging is
	 * not enabled. This saves a malloc and a free.
	 */
	if (!nvgpu_log_mask_enabled(g, gpu_dbg_dma))
		return;

	flags_str = nvgpu_dma_flags_to_str(g, flags);

	__nvgpu_log_dbg(g, gpu_dbg_dma,
			func, line,
			"DMA %s: [%s] size=%-7zu "
			"aligned=%-7zu total=%-10llukB %s",
			what, type,
			size, PAGE_ALIGN(size),
			g->dma_memory_used >> 10,
			flags_str);

	if (flags_str)
		nvgpu_kfree(g, flags_str);
}

#define dma_dbg_alloc(g, size, flags, type)				\
	__dma_dbg(g, size, flags, type, "alloc", __func__, __LINE__)
#define dma_dbg_free(g, size, flags, type)				\
	__dma_dbg(g, size, flags, type, "free", __func__, __LINE__)

/*
 * For after the DMA alloc is done.
 */
#define __dma_dbg_done(g, size, type, what)				\
	nvgpu_log(g, gpu_dbg_dma,					\
		  "DMA %s: [%s] size=%-7zu Done!",			\
		  what, type, size);					\

#define dma_dbg_alloc_done(g, size, type)				\
	__dma_dbg_done(g, size, type, "alloc")
#define dma_dbg_free_done(g, size, type)				\
	__dma_dbg_done(g, size, type, "free")

#if defined(CONFIG_GK20A_VIDMEM)
static u64 __nvgpu_dma_alloc(struct nvgpu_allocator *allocator, u64 at,
				size_t size)
{
	u64 addr = 0;

	if (at)
		addr = nvgpu_alloc_fixed(allocator, at, size, 0);
	else
		addr = nvgpu_alloc(allocator, size);

	return addr;
}
#endif

#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
static void nvgpu_dma_flags_to_attrs(unsigned long *attrs,
		unsigned long flags)
#define ATTR_ARG(x) *x
#else
static void nvgpu_dma_flags_to_attrs(struct dma_attrs *attrs,
		unsigned long flags)
#define ATTR_ARG(x) x
#endif
{
	if (flags & NVGPU_DMA_NO_KERNEL_MAPPING)
		dma_set_attr(DMA_ATTR_NO_KERNEL_MAPPING, ATTR_ARG(attrs));
	if (flags & NVGPU_DMA_FORCE_CONTIGUOUS)
		dma_set_attr(DMA_ATTR_FORCE_CONTIGUOUS, ATTR_ARG(attrs));
#undef ATTR_ARG
}

int nvgpu_dma_alloc_flags_sys(struct gk20a *g, unsigned long flags,
		size_t size, struct nvgpu_mem *mem)
{
	struct device *d = dev_from_gk20a(g);
	int err;
	dma_addr_t iova;
	NVGPU_DEFINE_DMA_ATTRS(dma_attrs);
	void *alloc_ret;

	if (nvgpu_mem_is_valid(mem)) {
		nvgpu_warn(g, "memory leak !!");
		WARN_ON(1);
	}

	/*
	 * WAR for IO coherent chips: the DMA API does not seem to generate
	 * mappings that work correctly. Unclear why - Bug ID: 2040115.
	 *
	 * Basically we just tell the DMA API not to map with NO_KERNEL_MAPPING
	 * and then make a vmap() ourselves.
	 */
	if (nvgpu_is_enabled(g, NVGPU_USE_COHERENT_SYSMEM))
		flags |= NVGPU_DMA_NO_KERNEL_MAPPING;

	/*
	 * Before the debug print so we see this in the total. But during
	 * cleanup in the fail path this has to be subtracted.
	 */
	g->dma_memory_used += PAGE_ALIGN(size);

	dma_dbg_alloc(g, size, flags, "sysmem");

	/*
	 * Save the old size but for actual allocation purposes the size is
	 * going to be page aligned.
	 */
	mem->size = size;
	size = PAGE_ALIGN(size);

	nvgpu_dma_flags_to_attrs(&dma_attrs, flags);

	alloc_ret = dma_alloc_attrs(d, size, &iova,
				    GFP_KERNEL|__GFP_ZERO,
				    NVGPU_DMA_ATTR(dma_attrs));
	if (!alloc_ret)
		return -ENOMEM;

	if (flags & NVGPU_DMA_NO_KERNEL_MAPPING) {
		mem->priv.pages = alloc_ret;
		err = nvgpu_get_sgtable_from_pages(g, &mem->priv.sgt,
						   mem->priv.pages,
						   iova, size);
	} else {
		mem->cpu_va = alloc_ret;
		err = nvgpu_get_sgtable_attrs(g, &mem->priv.sgt, mem->cpu_va,
					iova, size, flags);
	}
	if (err)
		goto fail_free_dma;

	if (nvgpu_is_enabled(g, NVGPU_USE_COHERENT_SYSMEM)) {
		mem->cpu_va = vmap(mem->priv.pages,
				   size >> PAGE_SHIFT,
				   0, PAGE_KERNEL);
		if (!mem->cpu_va) {
			err = -ENOMEM;
			goto fail_free_sgt;
		}
	}

	mem->aligned_size = size;
	mem->aperture = APERTURE_SYSMEM;
	mem->priv.flags = flags;

	dma_dbg_alloc_done(g, mem->size, "sysmem");

	return 0;

fail_free_sgt:
	nvgpu_free_sgtable(g, &mem->priv.sgt);
fail_free_dma:
	dma_free_attrs(d, size, alloc_ret, iova, NVGPU_DMA_ATTR(dma_attrs));
	mem->cpu_va = NULL;
	mem->priv.sgt = NULL;
	mem->size = 0;
	g->dma_memory_used -= mem->aligned_size;
	return err;
}

int nvgpu_dma_alloc_flags_vid_at(struct gk20a *g, unsigned long flags,
		size_t size, struct nvgpu_mem *mem, u64 at)
{
#if defined(CONFIG_GK20A_VIDMEM)
	u64 addr;
	int err;
	struct nvgpu_allocator *vidmem_alloc = g->mm.vidmem.cleared ?
		&g->mm.vidmem.allocator :
		&g->mm.vidmem.bootstrap_allocator;
	u64 before_pending;

	if (nvgpu_mem_is_valid(mem)) {
		nvgpu_warn(g, "memory leak !!");
		WARN_ON(1);
	}

	dma_dbg_alloc(g, size, flags, "vidmem");

	mem->size = size;
	size = PAGE_ALIGN(size);

	if (!nvgpu_alloc_initialized(&g->mm.vidmem.allocator))
		return -ENOSYS;

	/*
	 * Our own allocator doesn't have any flags yet, and we can't
	 * kernel-map these, so require explicit flags.
	 */
	WARN_ON(flags != NVGPU_DMA_NO_KERNEL_MAPPING);

	nvgpu_mutex_acquire(&g->mm.vidmem.clear_list_mutex);
	before_pending = atomic64_read(&g->mm.vidmem.bytes_pending.atomic_var);
	addr = __nvgpu_dma_alloc(vidmem_alloc, at, size);
	nvgpu_mutex_release(&g->mm.vidmem.clear_list_mutex);
	if (!addr) {
		/*
		 * If memory is known to be freed soon, let the user know that
		 * it may be available after a while.
		 */
		if (before_pending)
			return -EAGAIN;
		else
			return -ENOMEM;
	}

	if (at)
		mem->mem_flags |= NVGPU_MEM_FLAG_FIXED;

	mem->priv.sgt = nvgpu_kzalloc(g, sizeof(struct sg_table));
	if (!mem->priv.sgt) {
		err = -ENOMEM;
		goto fail_physfree;
	}

	err = sg_alloc_table(mem->priv.sgt, 1, GFP_KERNEL);
	if (err)
		goto fail_kfree;

	nvgpu_vidmem_set_page_alloc(mem->priv.sgt->sgl, addr);
	sg_set_page(mem->priv.sgt->sgl, NULL, size, 0);

	mem->aligned_size = size;
	mem->aperture = APERTURE_VIDMEM;
	mem->vidmem_alloc = (struct nvgpu_page_alloc *)(uintptr_t)addr;
	mem->allocator = vidmem_alloc;
	mem->priv.flags = flags;

	nvgpu_init_list_node(&mem->clear_list_entry);

	dma_dbg_alloc_done(g, mem->size, "vidmem");

	return 0;

fail_kfree:
	nvgpu_kfree(g, mem->priv.sgt);
fail_physfree:
	nvgpu_free(&g->mm.vidmem.allocator, addr);
	mem->size = 0;
	return err;
#else
	return -ENOSYS;
#endif
}

void nvgpu_dma_free_sys(struct gk20a *g, struct nvgpu_mem *mem)
{
	struct device *d = dev_from_gk20a(g);

	g->dma_memory_used -= mem->aligned_size;

	dma_dbg_free(g, mem->size, mem->priv.flags, "sysmem");

	if (!(mem->mem_flags & NVGPU_MEM_FLAG_SHADOW_COPY) &&
	    !(mem->mem_flags & __NVGPU_MEM_FLAG_NO_DMA) &&
	    (mem->cpu_va || mem->priv.pages)) {
		/*
		 * Free side of WAR for bug 2040115.
		 */
		if (nvgpu_is_enabled(g, NVGPU_USE_COHERENT_SYSMEM))
			vunmap(mem->cpu_va);

		if (mem->priv.flags) {
			NVGPU_DEFINE_DMA_ATTRS(dma_attrs);

			nvgpu_dma_flags_to_attrs(&dma_attrs, mem->priv.flags);

			if (mem->priv.flags & NVGPU_DMA_NO_KERNEL_MAPPING) {
				dma_free_attrs(d, mem->aligned_size, mem->priv.pages,
					sg_dma_address(mem->priv.sgt->sgl),
					NVGPU_DMA_ATTR(dma_attrs));
			} else {
				dma_free_attrs(d, mem->aligned_size, mem->cpu_va,
					sg_dma_address(mem->priv.sgt->sgl),
					NVGPU_DMA_ATTR(dma_attrs));
			}
		} else {
			dma_free_coherent(d, mem->aligned_size, mem->cpu_va,
					sg_dma_address(mem->priv.sgt->sgl));
		}
		mem->cpu_va = NULL;
		mem->priv.pages = NULL;
	}

	/*
	 * When this flag is set we expect that pages is still populated but not
	 * by the DMA API.
	 */
	if (mem->mem_flags & __NVGPU_MEM_FLAG_NO_DMA)
		nvgpu_kfree(g, mem->priv.pages);

	if ((mem->mem_flags & NVGPU_MEM_FLAG_FOREIGN_SGT) == 0 &&
			mem->priv.sgt != NULL) {
		nvgpu_free_sgtable(g, &mem->priv.sgt);
	}

	dma_dbg_free_done(g, mem->size, "sysmem");

	mem->size = 0;
	mem->aligned_size = 0;
	mem->aperture = APERTURE_INVALID;
}

void nvgpu_dma_free_vid(struct gk20a *g, struct nvgpu_mem *mem)
{
#if defined(CONFIG_GK20A_VIDMEM)
	size_t mem_size = mem->size;

	dma_dbg_free(g, mem->size, mem->priv.flags, "vidmem");

	/* Sanity check - only this supported when allocating. */
	WARN_ON(mem->priv.flags != NVGPU_DMA_NO_KERNEL_MAPPING);

	if (mem->mem_flags & NVGPU_MEM_FLAG_USER_MEM) {
		int err = nvgpu_vidmem_clear_list_enqueue(g, mem);

		/*
		 * If there's an error here then that means we can't clear the
		 * vidmem. That's too bad; however, we still own the nvgpu_mem
		 * buf so we have to free that.
		 *
		 * We don't need to worry about the vidmem allocator itself
		 * since when that gets cleaned up in the driver shutdown path
		 * all the outstanding allocs are force freed.
		 */
		if (err)
			nvgpu_kfree(g, mem);
	} else {
		nvgpu_memset(g, mem, 0, 0, mem->aligned_size);
		nvgpu_free(mem->allocator,
			   (u64)nvgpu_vidmem_get_page_alloc(mem->priv.sgt->sgl));
		nvgpu_free_sgtable(g, &mem->priv.sgt);

		mem->size = 0;
		mem->aligned_size = 0;
		mem->aperture = APERTURE_INVALID;
	}

	dma_dbg_free_done(g, mem_size, "vidmem");
#endif
}

int nvgpu_get_sgtable_attrs(struct gk20a *g, struct sg_table **sgt,
		      void *cpuva, u64 iova, size_t size, unsigned long flags)
{
	int err = 0;
	struct sg_table *tbl;
	NVGPU_DEFINE_DMA_ATTRS(dma_attrs);

	tbl = nvgpu_kzalloc(g, sizeof(struct sg_table));
	if (!tbl) {
		err = -ENOMEM;
		goto fail;
	}

	nvgpu_dma_flags_to_attrs(&dma_attrs, flags);
	err = dma_get_sgtable_attrs(dev_from_gk20a(g), tbl, cpuva, iova,
					size, NVGPU_DMA_ATTR(dma_attrs));
	if (err)
		goto fail;

	sg_dma_address(tbl->sgl) = iova;
	*sgt = tbl;

	return 0;

fail:
	if (tbl)
		nvgpu_kfree(g, tbl);

	return err;
}

int nvgpu_get_sgtable(struct gk20a *g, struct sg_table **sgt,
		      void *cpuva, u64 iova, size_t size)
{
	return nvgpu_get_sgtable_attrs(g, sgt, cpuva, iova, size, 0);
}

int nvgpu_get_sgtable_from_pages(struct gk20a *g, struct sg_table **sgt,
				 struct page **pages, u64 iova, size_t size)
{
	int err = 0;
	struct sg_table *tbl;

	tbl = nvgpu_kzalloc(g, sizeof(struct sg_table));
	if (!tbl) {
		err = -ENOMEM;
		goto fail;
	}

	err = sg_alloc_table_from_pages(tbl, pages,
					DIV_ROUND_UP(size, PAGE_SIZE),
					0, size, GFP_KERNEL);
	if (err)
		goto fail;

	sg_dma_address(tbl->sgl) = iova;
	*sgt = tbl;

	return 0;

fail:
	if (tbl)
		nvgpu_kfree(g, tbl);

	return err;
}

void nvgpu_free_sgtable(struct gk20a *g, struct sg_table **sgt)
{
	sg_free_table(*sgt);
	nvgpu_kfree(g, *sgt);
	*sgt = NULL;
}

bool nvgpu_iommuable(struct gk20a *g)
{
#ifdef CONFIG_TEGRA_GK20A
	struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);

	/*
	 * Check against the nvgpu device to see if it's been marked as
	 * IOMMU'able.
	 */
	if (!device_is_iommuable(l->dev))
		return false;
#endif

	return true;
}