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gpu: nvgpu: Remove GPU MMIO access on power/rail gate

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This is to weed out accesses to the GPU while it is gated. Otherwise
the accesses are silently dropped or cause a HW hang (on older chips).

Bug 1514949

Change-Id: Ice4cdb9f1f736978ebb3db847f39c7439bf98134
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/416339
Reviewed-by: Mitch Luban <mluban@nvidia.com>
This commit is contained in:
Alex Waterman
2014-05-23 13:29:53 -07:00
committed by Dan Willemsen
parent e2638d73fd
commit 0f9bf924b2
2 changed files with 41 additions and 0 deletions
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36
drivers/gpu/nvgpu/gk20a/gk20a.c
View File

@@ -164,6 +164,32 @@ static inline u32 sim_readl(struct gk20a *g, u32 r)
return readl(g->sim.regs+r);
}
/*
* Locks out the driver from accessing GPU registers. This prevents access to
* thse registers after the GPU has been clock or power gated. This should help
* find annoying bugs where register reads and writes are silently dropped
* after the GPU has been turned off. On older chips these reads and writes can
* also lock the entire CPU up.
*/
int gk20a_lockout_registers(struct gk20a *g)
{
g->regs = NULL;
g->bar1 = NULL;
return 0;
}
/*
* Undoes gk20a_lockout_registers().
*/
int gk20a_restore_registers(struct gk20a *g)
{
g->regs = g->regs_saved;
g->bar1 = g->bar1_saved;
return 0;
}
static void kunmap_and_free_iopage(void **kvaddr, struct page **page)
{
if (*kvaddr) {
@@ -676,6 +702,9 @@ static int gk20a_init_support(struct platform_device *dev)
goto fail;
}
g->regs_saved = g->regs;
g->bar1_saved = g->bar1;
/* Get interrupt numbers */
g->irq_nonstall = platform_get_irq(dev, 1);
if (g->irq_stall < 0 || g->irq_nonstall < 0) {
@@ -786,6 +815,9 @@ static int gk20a_pm_prepare_poweroff(struct device *dev)
g->power_on = false;
/* Stop CPU from accessing the GPU registers. */
gk20a_lockout_registers(g);
return ret;
}
@@ -820,6 +852,10 @@ static int gk20a_pm_finalize_poweron(struct device *dev)
trace_gk20a_finalize_poweron(dev_name(dev));
err = gk20a_restore_registers(g);
if (err)
return err;
nice_value = task_nice(current);
set_user_nice(current, -20);

5
drivers/gpu/nvgpu/gk20a/gk20a.h
View File

@@ -232,9 +232,11 @@ struct gk20a {
struct resource *reg_mem;
void __iomem *regs;
void __iomem *regs_saved;
struct resource *bar1_mem;
void __iomem *bar1;
void __iomem *bar1_saved;
bool power_on;
@@ -487,6 +489,9 @@ static inline void gk20a_mem_wr32(void *ptr, int w, u32 data)
}
/* register accessors */
int gk20a_lockout_registers(struct gk20a *g);
int gk20a_restore_registers(struct gk20a *g);
static inline void gk20a_writel(struct gk20a *g, u32 r, u32 v)
{
gk20a_dbg(gpu_dbg_reg, " r=0x%x v=0x%x", r, v);