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alistair23-linux/drivers/iommu/tegra-smmu.c
Thierry Reding 8918465163 memory: Add NVIDIA Tegra memory controller support 
The memory controller on NVIDIA Tegra exposes various knobs that can be
used to tune the behaviour of the clients attached to it.

Currently this driver sets up the latency allowance registers to the HW
defaults. Eventually an API should be exported by this driver (via a
custom API or a generic subsystem) to allow clients to register latency
requirements.

This driver also registers an IOMMU (SMMU) that's implemented by the
memory controller. It is supported on Tegra30, Tegra114 and Tegra124
currently. Tegra20 has a GART instead.

The Tegra SMMU operates on memory clients and SWGROUPs. A memory client
is a unidirectional, special-purpose DMA master. A SWGROUP represents a
set of memory clients that form a logical functional unit corresponding
to a single device. Typically a device has two clients: one client for
read transactions and one client for write transactions, but there are
also devices that have only read clients, but many of them (such as the
display controllers).

Because there is no 1:1 relationship between memory clients and devices
the driver keeps a table of memory clients and the SWGROUPs that they
belong to per SoC. Note that this is an exception and due to the fact
that the SMMU is tightly integrated with the rest of the Tegra SoC. The
use of these tables is discouraged in drivers for generic IOMMU devices
such as the ARM SMMU because the same IOMMU could be used in any number
of SoCs and keeping such tables for each SoC would not scale.

Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
2014-12-04 16:11:47 +01:00

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/*
* Copyright (C) 2011-2014 NVIDIA CORPORATION. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/err.h>
#include <linux/iommu.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <soc/tegra/ahb.h>
#include <soc/tegra/mc.h>
struct tegra_smmu {
void __iomem *regs;
struct device *dev;
struct tegra_mc *mc;
const struct tegra_smmu_soc *soc;
unsigned long *asids;
struct mutex lock;
struct list_head list;
};
struct tegra_smmu_as {
struct iommu_domain *domain;
struct tegra_smmu *smmu;
unsigned int use_count;
struct page *count;
struct page *pd;
unsigned id;
u32 attr;
};
static inline void smmu_writel(struct tegra_smmu *smmu, u32 value,
unsigned long offset)
{
writel(value, smmu->regs + offset);
}
static inline u32 smmu_readl(struct tegra_smmu *smmu, unsigned long offset)
{
return readl(smmu->regs + offset);
}
#define SMMU_CONFIG 0x010
#define SMMU_CONFIG_ENABLE (1 << 0)
#define SMMU_TLB_CONFIG 0x14
#define SMMU_TLB_CONFIG_HIT_UNDER_MISS (1 << 29)
#define SMMU_TLB_CONFIG_ROUND_ROBIN_ARBITRATION (1 << 28)
#define SMMU_TLB_CONFIG_ACTIVE_LINES(x) ((x) & 0x3f)
#define SMMU_PTC_CONFIG 0x18
#define SMMU_PTC_CONFIG_ENABLE (1 << 29)
#define SMMU_PTC_CONFIG_REQ_LIMIT(x) (((x) & 0x0f) << 24)
#define SMMU_PTC_CONFIG_INDEX_MAP(x) ((x) & 0x3f)
#define SMMU_PTB_ASID 0x01c
#define SMMU_PTB_ASID_VALUE(x) ((x) & 0x7f)
#define SMMU_PTB_DATA 0x020
#define SMMU_PTB_DATA_VALUE(page, attr) (page_to_phys(page) >> 12 | (attr))
#define SMMU_MK_PDE(page, attr) (page_to_phys(page) >> SMMU_PTE_SHIFT | (attr))
#define SMMU_TLB_FLUSH 0x030
#define SMMU_TLB_FLUSH_VA_MATCH_ALL (0 << 0)
#define SMMU_TLB_FLUSH_VA_MATCH_SECTION (2 << 0)
#define SMMU_TLB_FLUSH_VA_MATCH_GROUP (3 << 0)
#define SMMU_TLB_FLUSH_ASID(x) (((x) & 0x7f) << 24)
#define SMMU_TLB_FLUSH_VA_SECTION(addr) ((((addr) & 0xffc00000) >> 12) | \
SMMU_TLB_FLUSH_VA_MATCH_SECTION)
#define SMMU_TLB_FLUSH_VA_GROUP(addr) ((((addr) & 0xffffc000) >> 12) | \
SMMU_TLB_FLUSH_VA_MATCH_GROUP)
#define SMMU_TLB_FLUSH_ASID_MATCH (1 << 31)
#define SMMU_PTC_FLUSH 0x034
#define SMMU_PTC_FLUSH_TYPE_ALL (0 << 0)
#define SMMU_PTC_FLUSH_TYPE_ADR (1 << 0)
#define SMMU_PTC_FLUSH_HI 0x9b8
#define SMMU_PTC_FLUSH_HI_MASK 0x3
/* per-SWGROUP SMMU_*_ASID register */
#define SMMU_ASID_ENABLE (1 << 31)
#define SMMU_ASID_MASK 0x7f
#define SMMU_ASID_VALUE(x) ((x) & SMMU_ASID_MASK)
/* page table definitions */
#define SMMU_NUM_PDE 1024
#define SMMU_NUM_PTE 1024
#define SMMU_SIZE_PD (SMMU_NUM_PDE * 4)
#define SMMU_SIZE_PT (SMMU_NUM_PTE * 4)
#define SMMU_PDE_SHIFT 22
#define SMMU_PTE_SHIFT 12
#define SMMU_PFN_MASK 0x000fffff
#define SMMU_PD_READABLE (1 << 31)
#define SMMU_PD_WRITABLE (1 << 30)
#define SMMU_PD_NONSECURE (1 << 29)
#define SMMU_PDE_READABLE (1 << 31)
#define SMMU_PDE_WRITABLE (1 << 30)
#define SMMU_PDE_NONSECURE (1 << 29)
#define SMMU_PDE_NEXT (1 << 28)
#define SMMU_PTE_READABLE (1 << 31)
#define SMMU_PTE_WRITABLE (1 << 30)
#define SMMU_PTE_NONSECURE (1 << 29)
#define SMMU_PDE_ATTR (SMMU_PDE_READABLE | SMMU_PDE_WRITABLE | \
SMMU_PDE_NONSECURE)
#define SMMU_PTE_ATTR (SMMU_PTE_READABLE | SMMU_PTE_WRITABLE | \
SMMU_PTE_NONSECURE)
static inline void smmu_flush_ptc(struct tegra_smmu *smmu, struct page *page,
unsigned long offset)
{
phys_addr_t phys = page ? page_to_phys(page) : 0;
u32 value;
if (page) {
offset &= ~(smmu->mc->soc->atom_size - 1);
if (smmu->mc->soc->num_address_bits > 32) {
#ifdef CONFIG_PHYS_ADDR_T_64BIT
value = (phys >> 32) & SMMU_PTC_FLUSH_HI_MASK;
#else
value = 0;
#endif
smmu_writel(smmu, value, SMMU_PTC_FLUSH_HI);
}
value = (phys + offset) | SMMU_PTC_FLUSH_TYPE_ADR;
} else {
value = SMMU_PTC_FLUSH_TYPE_ALL;
}
smmu_writel(smmu, value, SMMU_PTC_FLUSH);
}
static inline void smmu_flush_tlb(struct tegra_smmu *smmu)
{
smmu_writel(smmu, SMMU_TLB_FLUSH_VA_MATCH_ALL, SMMU_TLB_FLUSH);
}
static inline void smmu_flush_tlb_asid(struct tegra_smmu *smmu,
unsigned long asid)
{
u32 value;
value = SMMU_TLB_FLUSH_ASID_MATCH | SMMU_TLB_FLUSH_ASID(asid) |
SMMU_TLB_FLUSH_VA_MATCH_ALL;
smmu_writel(smmu, value, SMMU_TLB_FLUSH);
}
static inline void smmu_flush_tlb_section(struct tegra_smmu *smmu,
unsigned long asid,
unsigned long iova)
{
u32 value;
value = SMMU_TLB_FLUSH_ASID_MATCH | SMMU_TLB_FLUSH_ASID(asid) |
SMMU_TLB_FLUSH_VA_SECTION(iova);
smmu_writel(smmu, value, SMMU_TLB_FLUSH);
}
static inline void smmu_flush_tlb_group(struct tegra_smmu *smmu,
unsigned long asid,
unsigned long iova)
{
u32 value;
value = SMMU_TLB_FLUSH_ASID_MATCH | SMMU_TLB_FLUSH_ASID(asid) |
SMMU_TLB_FLUSH_VA_GROUP(iova);
smmu_writel(smmu, value, SMMU_TLB_FLUSH);
}
static inline void smmu_flush(struct tegra_smmu *smmu)
{
smmu_readl(smmu, SMMU_CONFIG);
}
static int tegra_smmu_alloc_asid(struct tegra_smmu *smmu, unsigned int *idp)
{
unsigned long id;
mutex_lock(&smmu->lock);
id = find_first_zero_bit(smmu->asids, smmu->soc->num_asids);
if (id >= smmu->soc->num_asids) {
mutex_unlock(&smmu->lock);
return -ENOSPC;
}
set_bit(id, smmu->asids);
*idp = id;
mutex_unlock(&smmu->lock);
return 0;
}
static void tegra_smmu_free_asid(struct tegra_smmu *smmu, unsigned int id)
{
mutex_lock(&smmu->lock);
clear_bit(id, smmu->asids);
mutex_unlock(&smmu->lock);
}
static bool tegra_smmu_capable(enum iommu_cap cap)
{
return false;
}
static int tegra_smmu_domain_init(struct iommu_domain *domain)
{
struct tegra_smmu_as *as;
unsigned int i;
uint32_t *pd;
as = kzalloc(sizeof(*as), GFP_KERNEL);
if (!as)
return -ENOMEM;
as->attr = SMMU_PD_READABLE | SMMU_PD_WRITABLE | SMMU_PD_NONSECURE;
as->domain = domain;
as->pd = alloc_page(GFP_KERNEL | __GFP_DMA);
if (!as->pd) {
kfree(as);
return -ENOMEM;
}
as->count = alloc_page(GFP_KERNEL);
if (!as->count) {
__free_page(as->pd);
kfree(as);
return -ENOMEM;
}
/* clear PDEs */
pd = page_address(as->pd);
SetPageReserved(as->pd);
for (i = 0; i < SMMU_NUM_PDE; i++)
pd[i] = 0;
/* clear PDE usage counters */
pd = page_address(as->count);
SetPageReserved(as->count);
for (i = 0; i < SMMU_NUM_PDE; i++)
pd[i] = 0;
domain->priv = as;
return 0;
}
static void tegra_smmu_domain_destroy(struct iommu_domain *domain)
{
struct tegra_smmu_as *as = domain->priv;
/* TODO: free page directory and page tables */
ClearPageReserved(as->pd);
kfree(as);
}
static const struct tegra_smmu_swgroup *
tegra_smmu_find_swgroup(struct tegra_smmu *smmu, unsigned int swgroup)
{
const struct tegra_smmu_swgroup *group = NULL;
unsigned int i;
for (i = 0; i < smmu->soc->num_swgroups; i++) {
if (smmu->soc->swgroups[i].swgroup == swgroup) {
group = &smmu->soc->swgroups[i];
break;
}
}
return group;
}
static void tegra_smmu_enable(struct tegra_smmu *smmu, unsigned int swgroup,
unsigned int asid)
{
const struct tegra_smmu_swgroup *group;
unsigned int i;
u32 value;
for (i = 0; i < smmu->soc->num_clients; i++) {
const struct tegra_mc_client *client = &smmu->soc->clients[i];
if (client->swgroup != swgroup)
continue;
value = smmu_readl(smmu, client->smmu.reg);
value |= BIT(client->smmu.bit);
smmu_writel(smmu, value, client->smmu.reg);
}
group = tegra_smmu_find_swgroup(smmu, swgroup);
if (group) {
value = smmu_readl(smmu, group->reg);
value &= ~SMMU_ASID_MASK;
value |= SMMU_ASID_VALUE(asid);
value |= SMMU_ASID_ENABLE;
smmu_writel(smmu, value, group->reg);
}
}
static void tegra_smmu_disable(struct tegra_smmu *smmu, unsigned int swgroup,
unsigned int asid)
{
const struct tegra_smmu_swgroup *group;
unsigned int i;
u32 value;
group = tegra_smmu_find_swgroup(smmu, swgroup);
if (group) {
value = smmu_readl(smmu, group->reg);
value &= ~SMMU_ASID_MASK;
value |= SMMU_ASID_VALUE(asid);
value &= ~SMMU_ASID_ENABLE;
smmu_writel(smmu, value, group->reg);
}
for (i = 0; i < smmu->soc->num_clients; i++) {
const struct tegra_mc_client *client = &smmu->soc->clients[i];
if (client->swgroup != swgroup)
continue;
value = smmu_readl(smmu, client->smmu.reg);
value &= ~BIT(client->smmu.bit);
smmu_writel(smmu, value, client->smmu.reg);
}
}
static int tegra_smmu_as_prepare(struct tegra_smmu *smmu,
struct tegra_smmu_as *as)
{
u32 value;
int err;
if (as->use_count > 0) {
as->use_count++;
return 0;
}
err = tegra_smmu_alloc_asid(smmu, &as->id);
if (err < 0)
return err;
smmu->soc->ops->flush_dcache(as->pd, 0, SMMU_SIZE_PD);
smmu_flush_ptc(smmu, as->pd, 0);
smmu_flush_tlb_asid(smmu, as->id);
smmu_writel(smmu, as->id & 0x7f, SMMU_PTB_ASID);
value = SMMU_PTB_DATA_VALUE(as->pd, as->attr);
smmu_writel(smmu, value, SMMU_PTB_DATA);
smmu_flush(smmu);
as->smmu = smmu;
as->use_count++;
return 0;
}
static void tegra_smmu_as_unprepare(struct tegra_smmu *smmu,
struct tegra_smmu_as *as)
{
if (--as->use_count > 0)
return;
tegra_smmu_free_asid(smmu, as->id);
as->smmu = NULL;
}
static int tegra_smmu_attach_dev(struct iommu_domain *domain,
struct device *dev)
{
struct tegra_smmu *smmu = dev->archdata.iommu;
struct tegra_smmu_as *as = domain->priv;
struct device_node *np = dev->of_node;
struct of_phandle_args args;
unsigned int index = 0;
int err = 0;
while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
&args)) {
unsigned int swgroup = args.args[0];
if (args.np != smmu->dev->of_node) {
of_node_put(args.np);
continue;
}
of_node_put(args.np);
err = tegra_smmu_as_prepare(smmu, as);
if (err < 0)
return err;
tegra_smmu_enable(smmu, swgroup, as->id);
index++;
}
if (index == 0)
return -ENODEV;
return 0;
}
static void tegra_smmu_detach_dev(struct iommu_domain *domain, struct device *dev)
{
struct tegra_smmu_as *as = domain->priv;
struct device_node *np = dev->of_node;
struct tegra_smmu *smmu = as->smmu;
struct of_phandle_args args;
unsigned int index = 0;
while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
&args)) {
unsigned int swgroup = args.args[0];
if (args.np != smmu->dev->of_node) {
of_node_put(args.np);
continue;
}
of_node_put(args.np);
tegra_smmu_disable(smmu, swgroup, as->id);
tegra_smmu_as_unprepare(smmu, as);
index++;
}
}
static u32 *as_get_pte(struct tegra_smmu_as *as, dma_addr_t iova,
struct page **pagep)
{
u32 *pd = page_address(as->pd), *pt, *count;
u32 pde = (iova >> SMMU_PDE_SHIFT) & 0x3ff;
u32 pte = (iova >> SMMU_PTE_SHIFT) & 0x3ff;
struct tegra_smmu *smmu = as->smmu;
struct page *page;
unsigned int i;
if (pd[pde] == 0) {
page = alloc_page(GFP_KERNEL | __GFP_DMA);
if (!page)
return NULL;
pt = page_address(page);
SetPageReserved(page);
for (i = 0; i < SMMU_NUM_PTE; i++)
pt[i] = 0;
smmu->soc->ops->flush_dcache(page, 0, SMMU_SIZE_PT);
pd[pde] = SMMU_MK_PDE(page, SMMU_PDE_ATTR | SMMU_PDE_NEXT);
smmu->soc->ops->flush_dcache(as->pd, pde << 2, 4);
smmu_flush_ptc(smmu, as->pd, pde << 2);
smmu_flush_tlb_section(smmu, as->id, iova);
smmu_flush(smmu);
} else {
page = pfn_to_page(pd[pde] & SMMU_PFN_MASK);
pt = page_address(page);
}
*pagep = page;
/* Keep track of entries in this page table. */
count = page_address(as->count);
if (pt[pte] == 0)
count[pde]++;
return &pt[pte];
}
static void as_put_pte(struct tegra_smmu_as *as, dma_addr_t iova)
{
u32 pde = (iova >> SMMU_PDE_SHIFT) & 0x3ff;
u32 pte = (iova >> SMMU_PTE_SHIFT) & 0x3ff;
u32 *count = page_address(as->count);
u32 *pd = page_address(as->pd), *pt;
struct page *page;
page = pfn_to_page(pd[pde] & SMMU_PFN_MASK);
pt = page_address(page);
/*
* When no entries in this page table are used anymore, return the
* memory page to the system.
*/
if (pt[pte] != 0) {
if (--count[pde] == 0) {
ClearPageReserved(page);
__free_page(page);
pd[pde] = 0;
}
pt[pte] = 0;
}
}
static int tegra_smmu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot)
{
struct tegra_smmu_as *as = domain->priv;
struct tegra_smmu *smmu = as->smmu;
unsigned long offset;
struct page *page;
u32 *pte;
pte = as_get_pte(as, iova, &page);
if (!pte)
return -ENOMEM;
*pte = __phys_to_pfn(paddr) | SMMU_PTE_ATTR;
offset = offset_in_page(pte);
smmu->soc->ops->flush_dcache(page, offset, 4);
smmu_flush_ptc(smmu, page, offset);
smmu_flush_tlb_group(smmu, as->id, iova);
smmu_flush(smmu);
return 0;
}
static size_t tegra_smmu_unmap(struct iommu_domain *domain, unsigned long iova,
size_t size)
{
struct tegra_smmu_as *as = domain->priv;
struct tegra_smmu *smmu = as->smmu;
unsigned long offset;
struct page *page;
u32 *pte;
pte = as_get_pte(as, iova, &page);
if (!pte)
return 0;
offset = offset_in_page(pte);
as_put_pte(as, iova);
smmu->soc->ops->flush_dcache(page, offset, 4);
smmu_flush_ptc(smmu, page, offset);
smmu_flush_tlb_group(smmu, as->id, iova);
smmu_flush(smmu);
return size;
}
static phys_addr_t tegra_smmu_iova_to_phys(struct iommu_domain *domain,
dma_addr_t iova)
{
struct tegra_smmu_as *as = domain->priv;
struct page *page;
unsigned long pfn;
u32 *pte;
pte = as_get_pte(as, iova, &page);
pfn = *pte & SMMU_PFN_MASK;
return PFN_PHYS(pfn);
}
static struct tegra_smmu *tegra_smmu_find(struct device_node *np)
{
struct platform_device *pdev;
struct tegra_mc *mc;
pdev = of_find_device_by_node(np);
if (!pdev)
return NULL;
mc = platform_get_drvdata(pdev);
if (!mc)
return NULL;
return mc->smmu;
}
static int tegra_smmu_add_device(struct device *dev)
{
struct device_node *np = dev->of_node;
struct of_phandle_args args;
unsigned int index = 0;
while (of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
&args) == 0) {
struct tegra_smmu *smmu;
smmu = tegra_smmu_find(args.np);
if (smmu) {
/*
* Only a single IOMMU master interface is currently
* supported by the Linux kernel, so abort after the
* first match.
*/
dev->archdata.iommu = smmu;
break;
}
index++;
}
return 0;
}
static void tegra_smmu_remove_device(struct device *dev)
{
dev->archdata.iommu = NULL;
}
static const struct iommu_ops tegra_smmu_ops = {
.capable = tegra_smmu_capable,
.domain_init = tegra_smmu_domain_init,
.domain_destroy = tegra_smmu_domain_destroy,
.attach_dev = tegra_smmu_attach_dev,
.detach_dev = tegra_smmu_detach_dev,
.add_device = tegra_smmu_add_device,
.remove_device = tegra_smmu_remove_device,
.map = tegra_smmu_map,
.unmap = tegra_smmu_unmap,
.map_sg = default_iommu_map_sg,
.iova_to_phys = tegra_smmu_iova_to_phys,
.pgsize_bitmap = SZ_4K,
};
static void tegra_smmu_ahb_enable(void)
{
static const struct of_device_id ahb_match[] = {
{ .compatible = "nvidia,tegra30-ahb", },
{ }
};
struct device_node *ahb;
ahb = of_find_matching_node(NULL, ahb_match);
if (ahb) {
tegra_ahb_enable_smmu(ahb);
of_node_put(ahb);
}
}
struct tegra_smmu *tegra_smmu_probe(struct device *dev,
const struct tegra_smmu_soc *soc,
struct tegra_mc *mc)
{
struct tegra_smmu *smmu;
size_t size;
u32 value;
int err;
/* This can happen on Tegra20 which doesn't have an SMMU */
if (!soc)
return NULL;
smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
if (!smmu)
return ERR_PTR(-ENOMEM);
/*
* This is a bit of a hack. Ideally we'd want to simply return this
* value. However the IOMMU registration process will attempt to add
* all devices to the IOMMU when bus_set_iommu() is called. In order
* not to rely on global variables to track the IOMMU instance, we
* set it here so that it can be looked up from the .add_device()
* callback via the IOMMU device's .drvdata field.
*/
mc->smmu = smmu;
size = BITS_TO_LONGS(soc->num_asids) * sizeof(long);
smmu->asids = devm_kzalloc(dev, size, GFP_KERNEL);
if (!smmu->asids)
return ERR_PTR(-ENOMEM);
mutex_init(&smmu->lock);
smmu->regs = mc->regs;
smmu->soc = soc;
smmu->dev = dev;
smmu->mc = mc;
value = SMMU_PTC_CONFIG_ENABLE | SMMU_PTC_CONFIG_INDEX_MAP(0x3f);
if (soc->supports_request_limit)
value |= SMMU_PTC_CONFIG_REQ_LIMIT(8);
smmu_writel(smmu, value, SMMU_PTC_CONFIG);
value = SMMU_TLB_CONFIG_HIT_UNDER_MISS |
SMMU_TLB_CONFIG_ACTIVE_LINES(0x20);
if (soc->supports_round_robin_arbitration)
value |= SMMU_TLB_CONFIG_ROUND_ROBIN_ARBITRATION;
smmu_writel(smmu, value, SMMU_TLB_CONFIG);
smmu_flush_ptc(smmu, NULL, 0);
smmu_flush_tlb(smmu);
smmu_writel(smmu, SMMU_CONFIG_ENABLE, SMMU_CONFIG);
smmu_flush(smmu);
tegra_smmu_ahb_enable();
err = bus_set_iommu(&platform_bus_type, &tegra_smmu_ops);
if (err < 0)
return ERR_PTR(err);
return smmu;
}
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