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digetxjoergroedel
digetx
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iommu/tegra: gart: Simplify clients-tracking code
GART is a simple IOMMU provider that has single address space. There is no need to setup global clients list and manage it for tracking of the active domain, hence lot's of code could be safely removed and replaced with a simpler alternative. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Acked-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
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‎drivers/iommu/tegra-gart.c

Lines changed: 40 additions & 115 deletions
Original file line numberDiff line numberDiff line change
@@ -23,7 +23,6 @@
2323

2424
#include <linux/io.h>
2525
#include <linux/iommu.h>
26-
#include <linux/list.h>
2726
#include <linux/moduleparam.h>
2827
#include <linux/platform_device.h>
2928
#include <linux/slab.h>
@@ -46,42 +45,27 @@
4645
#define GART_PAGE_MASK \
4746
(~(GART_PAGE_SIZE - 1) & ~GART_ENTRY_PHYS_ADDR_VALID)
4847

49-
struct gart_client {
50-
struct device *dev;
51-
struct list_head list;
52-
};
53-
5448
struct gart_device {
5549
void __iomem *regs;
5650
u32 *savedata;
5751
u32 page_count; /* total remappable size */
5852
dma_addr_t iovmm_base; /* offset to vmm_area */
5953
spinlock_t pte_lock; /* for pagetable */
60-
struct list_head client;
61-
spinlock_t client_lock; /* for client list */
54+
spinlock_t dom_lock; /* for active domain */
55+
unsigned int active_devices; /* number of active devices */
6256
struct iommu_domain *active_domain; /* current active domain */
6357
struct device *dev;
6458

6559
struct iommu_device iommu; /* IOMMU Core handle */
6660
};
6761

68-
struct gart_domain {
69-
struct iommu_domain domain; /* generic domain handle */
70-
struct gart_device *gart; /* link to gart device */
71-
};
72-
7362
static struct gart_device *gart_handle; /* unique for a system */
7463

7564
static bool gart_debug;
7665

7766
#define GART_PTE(_pfn) \
7867
(GART_ENTRY_PHYS_ADDR_VALID | ((_pfn) << PAGE_SHIFT))
7968

80-
static struct gart_domain *to_gart_domain(struct iommu_domain *dom)
81-
{
82-
return container_of(dom, struct gart_domain, domain);
83-
}
84-
8569
/*
8670
* Any interaction between any block on PPSB and a block on APB or AHB
8771
* must have these read-back to ensure the APB/AHB bus transaction is
@@ -170,125 +154,70 @@ static inline bool gart_iova_range_valid(struct gart_device *gart,
170154
static int gart_iommu_attach_dev(struct iommu_domain *domain,
171155
struct device *dev)
172156
{
173-
struct gart_domain *gart_domain = to_gart_domain(domain);
174157
struct gart_device *gart = gart_handle;
175-
struct gart_client *client, *c;
176-
int err = 0;
177-
178-
client = kzalloc(sizeof(*c), GFP_KERNEL);
179-
if (!client)
180-
return -ENOMEM;
181-
client->dev = dev;
182-
183-
spin_lock(&gart->client_lock);
184-
list_for_each_entry(c, &gart->client, list) {
185-
if (c->dev == dev) {
186-
dev_err(gart->dev,
187-
"%s is already attached\n", dev_name(dev));
188-
err = -EINVAL;
189-
goto fail;
190-
}
191-
}
192-
if (gart->active_domain && gart->active_domain != domain) {
193-
dev_err(gart->dev, "Only one domain can be active at a time\n");
194-
err = -EINVAL;
195-
goto fail;
196-
}
197-
gart->active_domain = domain;
198-
gart_domain->gart = gart;
199-
list_add(&client->list, &gart->client);
200-
spin_unlock(&gart->client_lock);
201-
dev_dbg(gart->dev, "Attached %s\n", dev_name(dev));
202-
return 0;
158+
int ret = 0;
203159

204-
fail:
205-
kfree(client);
206-
spin_unlock(&gart->client_lock);
207-
return err;
208-
}
160+
spin_lock(&gart->dom_lock);
209161

210-
static void __gart_iommu_detach_dev(struct iommu_domain *domain,
211-
struct device *dev)
212-
{
213-
struct gart_domain *gart_domain = to_gart_domain(domain);
214-
struct gart_device *gart = gart_domain->gart;
215-
struct gart_client *c;
216-
217-
list_for_each_entry(c, &gart->client, list) {
218-
if (c->dev == dev) {
219-
list_del(&c->list);
220-
kfree(c);
221-
if (list_empty(&gart->client)) {
222-
gart->active_domain = NULL;
223-
gart_domain->gart = NULL;
224-
}
225-
dev_dbg(gart->dev, "Detached %s\n", dev_name(dev));
226-
return;
227-
}
162+
if (gart->active_domain && gart->active_domain != domain) {
163+
ret = -EBUSY;
164+
} else if (dev->archdata.iommu != domain) {
165+
dev->archdata.iommu = domain;
166+
gart->active_domain = domain;
167+
gart->active_devices++;
228168
}
229169

230-
dev_err(gart->dev, "Couldn't find %s to detach\n", dev_name(dev));
170+
spin_unlock(&gart->dom_lock);
171+
172+
return ret;
231173
}
232174

233175
static void gart_iommu_detach_dev(struct iommu_domain *domain,
234176
struct device *dev)
235177
{
236-
struct gart_domain *gart_domain = to_gart_domain(domain);
237-
struct gart_device *gart = gart_domain->gart;
178+
struct gart_device *gart = gart_handle;
179+
180+
spin_lock(&gart->dom_lock);
238181

239-
spin_lock(&gart->client_lock);
240-
__gart_iommu_detach_dev(domain, dev);
241-
spin_unlock(&gart->client_lock);
182+
if (dev->archdata.iommu == domain) {
183+
dev->archdata.iommu = NULL;
184+
185+
if (--gart->active_devices == 0)
186+
gart->active_domain = NULL;
187+
}
188+
189+
spin_unlock(&gart->dom_lock);
242190
}
243191

244192
static struct iommu_domain *gart_iommu_domain_alloc(unsigned type)
245193
{
246-
struct gart_domain *gart_domain;
247-
struct gart_device *gart;
194+
struct gart_device *gart = gart_handle;
195+
struct iommu_domain *domain;
248196

249197
if (type != IOMMU_DOMAIN_UNMANAGED)
250198
return NULL;
251199

252-
gart = gart_handle;
253-
if (!gart)
254-
return NULL;
255-
256-
gart_domain = kzalloc(sizeof(*gart_domain), GFP_KERNEL);
257-
if (!gart_domain)
258-
return NULL;
259-
260-
gart_domain->domain.geometry.aperture_start = gart->iovmm_base;
261-
gart_domain->domain.geometry.aperture_end = gart->iovmm_base +
200+
domain = kzalloc(sizeof(*domain), GFP_KERNEL);
201+
if (domain) {
202+
domain->geometry.aperture_start = gart->iovmm_base;
203+
domain->geometry.aperture_end = gart->iovmm_base +
262204
gart->page_count * GART_PAGE_SIZE - 1;
263-
gart_domain->domain.geometry.force_aperture = true;
205+
domain->geometry.force_aperture = true;
206+
}
264207

265-
return &gart_domain->domain;
208+
return domain;
266209
}
267210

268211
static void gart_iommu_domain_free(struct iommu_domain *domain)
269212
{
270-
struct gart_domain *gart_domain = to_gart_domain(domain);
271-
struct gart_device *gart = gart_domain->gart;
272-
273-
if (gart) {
274-
spin_lock(&gart->client_lock);
275-
if (!list_empty(&gart->client)) {
276-
struct gart_client *c, *tmp;
277-
278-
list_for_each_entry_safe(c, tmp, &gart->client, list)
279-
__gart_iommu_detach_dev(domain, c->dev);
280-
}
281-
spin_unlock(&gart->client_lock);
282-
}
283-
284-
kfree(gart_domain);
213+
WARN_ON(gart_handle->active_domain == domain);
214+
kfree(domain);
285215
}
286216

287217
static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova,
288218
phys_addr_t pa, size_t bytes, int prot)
289219
{
290-
struct gart_domain *gart_domain = to_gart_domain(domain);
291-
struct gart_device *gart = gart_domain->gart;
220+
struct gart_device *gart = gart_handle;
292221
unsigned long flags;
293222
unsigned long pfn;
294223
unsigned long pte;
@@ -319,8 +248,7 @@ static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova,
319248
static size_t gart_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
320249
size_t bytes)
321250
{
322-
struct gart_domain *gart_domain = to_gart_domain(domain);
323-
struct gart_device *gart = gart_domain->gart;
251+
struct gart_device *gart = gart_handle;
324252
unsigned long flags;
325253

326254
if (!gart_iova_range_valid(gart, iova, bytes))
@@ -335,8 +263,7 @@ static size_t gart_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
335263
static phys_addr_t gart_iommu_iova_to_phys(struct iommu_domain *domain,
336264
dma_addr_t iova)
337265
{
338-
struct gart_domain *gart_domain = to_gart_domain(domain);
339-
struct gart_device *gart = gart_domain->gart;
266+
struct gart_device *gart = gart_handle;
340267
unsigned long pte;
341268
phys_addr_t pa;
342269
unsigned long flags;
@@ -395,8 +322,7 @@ static int gart_iommu_of_xlate(struct device *dev,
395322

396323
static void gart_iommu_sync(struct iommu_domain *domain)
397324
{
398-
struct gart_domain *gart_domain = to_gart_domain(domain);
399-
struct gart_device *gart = gart_domain->gart;
325+
struct gart_device *gart = gart_handle;
400326

401327
FLUSH_GART_REGS(gart);
402328
}
@@ -483,8 +409,7 @@ struct gart_device *tegra_gart_probe(struct device *dev, struct tegra_mc *mc)
483409
gart->dev = dev;
484410
gart_regs = mc->regs + GART_REG_BASE;
485411
spin_lock_init(&gart->pte_lock);
486-
spin_lock_init(&gart->client_lock);
487-
INIT_LIST_HEAD(&gart->client);
412+
spin_lock_init(&gart->dom_lock);
488413
gart->regs = gart_regs;
489414
gart->iovmm_base = (dma_addr_t)res_remap->start;
490415
gart->page_count = (resource_size(res_remap) >> GART_PAGE_SHIFT);

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