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gpu: nvgpu: prevent hang on failing arbiter init

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The current code can lead to application hang when
opening device on first time if the arbiter fails
to set the clocks

Also it solves a buffer overrun condition in case
the requested frequency is above the maximum range
of the VF curve

bug 1835042

Change-Id: I385401ea27d5cc4bfa41b7ca2eb3a1db53138418
Signed-off-by: David Nieto <dmartineznie@nvidia.com>
Reviewed-on: http://git-master/r/1245911
Reviewed-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/1268061
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
This commit is contained in:
David Nieto
2016-11-01 11:29:39 -07:00
committed by Deepak Nibade
parent 136a9919e6
commit 1f0a38797f
1 changed files with 29 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

46
drivers/gpu/nvgpu/clk/clk_arb.c
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@@ -83,6 +83,7 @@ struct nvgpu_clk_arb {
struct llist_head requests;
struct gk20a *g;
int status;
struct nvgpu_clk_arb_target actual_pool[2];
struct nvgpu_clk_arb_target *actual;
@@ -269,7 +270,8 @@ int nvgpu_clk_arb_init_arbiter(struct gk20a *g)
atomic_read(&arb->req_nr));
} while (!atomic_read(&arb->req_nr));
return 0;
return arb->status;
init_fail:
@@ -533,6 +535,7 @@ static int nvgpu_clk_arb_update_vf_table(struct nvgpu_clk_arb *arb)
clk_cur = table->mclk_points[j].mhz;
j++;
num_points++;
}
}
table->mclk_num_points = num_points;
@@ -605,7 +608,7 @@ static void nvgpu_clk_arb_run_vf_table_cb(struct work_struct *work)
err = clk_vf_point_cache(g);
if (err) {
gk20a_err(dev_from_gk20a(g),
"failed to get GPC2CLK SRAM voltage");
"failed to cache VF table");
return;
}
nvgpu_clk_arb_update_vf_table(arb);
@@ -625,7 +628,7 @@ static void nvgpu_clk_arb_run_arbiter_cb(struct work_struct *work)
u32 voltuv, voltuv_sram;
bool mclk_set, gpc2clk_set;
int status;
int status = 0;
/* Temporary variables for checking target frequency */
u16 gpc2clk_target, mclk_target;
@@ -742,15 +745,21 @@ static void nvgpu_clk_arb_run_arbiter_cb(struct work_struct *work)
actual->gpc2clk = gpc2clk_target;
actual->mclk = mclk_target;
arb->voltuv_actual = voltuv;
arb->status = status;
/* Make changes visible to other threads */
smp_wmb();
xchg(&arb->actual, actual);
/* status must be visible before atomic inc */
smp_wmb();
atomic_inc(&arb->req_nr);
wake_up_interruptible(&arb->request_wq);
if (status < 0)
gk20a_err(dev_from_gk20a(g),
"Error in arbiter update");
#ifdef CONFIG_DEBUG_FS
g->ops.read_ptimer(g, &t1);
@@ -1016,20 +1025,23 @@ static void nvgpu_clk_arb_find_vf_point(struct nvgpu_clk_arb *arb,
struct nvgpu_clk_vf_table *table;
u32 index;
gpc2clk_target = *gpc2clk;
mclk_target = *mclk;
gpc2clk_voltuv = 0;
gpc2clk_voltuv_sram = 0;
mclk_voltuv = 0;
mclk_voltuv_sram = 0;
do {
gpc2clk_target = *gpc2clk;
mclk_target = *mclk;
gpc2clk_voltuv = 0;
gpc2clk_voltuv_sram = 0;
mclk_voltuv = 0;
mclk_voltuv_sram = 0;
table = ACCESS_ONCE(arb->current_vf_table);
/* pointer to table can be updated by callback */
smp_rmb();
if (!table)
continue;
if ((!table->gpc2clk_num_points) || (!table->mclk_num_points))
goto find_exit;
/* round up the freq requests */
for (index = 0; index < table->gpc2clk_num_points; index++) {
if (table->gpc2clk_points[index].mhz >=
@@ -1045,10 +1057,10 @@ static void nvgpu_clk_arb_find_vf_point(struct nvgpu_clk_arb *arb,
}
if (index == table->gpc2clk_num_points) {
gpc2clk_target = table->gpc2clk_points[index].mhz;
gpc2clk_voltuv = table->gpc2clk_points[index].uvolt;
gpc2clk_target = table->gpc2clk_points[index-1].mhz;
gpc2clk_voltuv = table->gpc2clk_points[index-1].uvolt;
gpc2clk_voltuv_sram =
table->gpc2clk_points[index].uvolt_sram;
table->gpc2clk_points[index-1].uvolt_sram;
}
for (index = 0; index < table->mclk_num_points; index++) {
@@ -1061,14 +1073,15 @@ static void nvgpu_clk_arb_find_vf_point(struct nvgpu_clk_arb *arb,
}
}
if (index == table->mclk_num_points) {
mclk_target = table->mclk_points[index].mhz;
mclk_voltuv = table->mclk_points[index].uvolt;
mclk_target = table->mclk_points[index-1].mhz;
mclk_voltuv = table->mclk_points[index-1].uvolt;
mclk_voltuv_sram =
table->mclk_points[index].uvolt_sram;
table->mclk_points[index-1].uvolt_sram;
}
} while (!table ||
(ACCESS_ONCE(arb->current_vf_table) != table));
find_exit:
*voltuv = gpc2clk_voltuv > mclk_voltuv ? gpc2clk_voltuv : mclk_voltuv;
*voltuv_sram = gpc2clk_voltuv_sram > mclk_voltuv_sram ?
gpc2clk_voltuv_sram : mclk_voltuv_sram;
@@ -1136,7 +1149,6 @@ static int nvgpu_clk_arb_change_vf_point(struct gk20a *g, u16 gpc2clk_target,
status = clk_program_fll_clks(g, &fllclk);
if (status < 0)
return status;
}
return 0;