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authorRobin Murphy <robin.murphy@arm.com>2016-02-01 15:00:48 +0300
committerDaniel Lezcano <daniel.lezcano@linaro.org>2016-02-25 16:30:15 +0300
commite392d603f61767cb2de4d82bb55a035918f8342c (patch)
tree1051148f6bec4a0bea199d2302858621a9ce9c5d /drivers/clocksource
parentbbf66d897adf2bb0c310db96c97e8db6369f39e1 (diff)
downloadlinux-e392d603f61767cb2de4d82bb55a035918f8342c.tar.xz
clocksource/drivers/arm_arch_timer: Enable and verify MMIO access
So far, we have been blindly assuming that having access to a memory-mapped timer frame implies that the individual elements of that frame frame are already enabled. Whilst it's the firmware's job to give us non-secure access to frames in the first place, we should not rely on implementations always being generous enough to also configure CNTACR for those non-secure frames (e.g. [1]). Explicitly enable feature-level access per-frame, and verify that the access we want is really implemented before trying to make use of it. [1]:https://github.com/ARM-software/tf-issues/issues/170 Acked-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Tested-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/arm_arch_timer.c36
1 files changed, 28 insertions, 8 deletions
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index c64d543d64bf..7c567f0c87f5 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -32,6 +32,14 @@
#define CNTTIDR 0x08
#define CNTTIDR_VIRT(n) (BIT(1) << ((n) * 4))
+#define CNTACR(n) (0x40 + ((n) * 4))
+#define CNTACR_RPCT BIT(0)
+#define CNTACR_RVCT BIT(1)
+#define CNTACR_RFRQ BIT(2)
+#define CNTACR_RVOFF BIT(3)
+#define CNTACR_RWVT BIT(4)
+#define CNTACR_RWPT BIT(5)
+
#define CNTVCT_LO 0x08
#define CNTVCT_HI 0x0c
#define CNTFRQ 0x10
@@ -757,7 +765,6 @@ static void __init arch_timer_mem_init(struct device_node *np)
}
cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
- iounmap(cntctlbase);
/*
* Try to find a virtual capable frame. Otherwise fall back to a
@@ -765,20 +772,31 @@ static void __init arch_timer_mem_init(struct device_node *np)
*/
for_each_available_child_of_node(np, frame) {
int n;
+ u32 cntacr;
if (of_property_read_u32(frame, "frame-number", &n)) {
pr_err("arch_timer: Missing frame-number\n");
- of_node_put(best_frame);
of_node_put(frame);
- return;
+ goto out;
}
- if (cnttidr & CNTTIDR_VIRT(n)) {
+ /* Try enabling everything, and see what sticks */
+ cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT |
+ CNTACR_RWVT | CNTACR_RVOFF | CNTACR_RVCT;
+ writel_relaxed(cntacr, cntctlbase + CNTACR(n));
+ cntacr = readl_relaxed(cntctlbase + CNTACR(n));
+
+ if ((cnttidr & CNTTIDR_VIRT(n)) &&
+ !(~cntacr & (CNTACR_RWVT | CNTACR_RVCT))) {
of_node_put(best_frame);
best_frame = frame;
arch_timer_mem_use_virtual = true;
break;
}
+
+ if (~cntacr & (CNTACR_RWPT | CNTACR_RPCT))
+ continue;
+
of_node_put(best_frame);
best_frame = of_node_get(frame);
}
@@ -786,24 +804,26 @@ static void __init arch_timer_mem_init(struct device_node *np)
base = arch_counter_base = of_iomap(best_frame, 0);
if (!base) {
pr_err("arch_timer: Can't map frame's registers\n");
- of_node_put(best_frame);
- return;
+ goto out;
}
if (arch_timer_mem_use_virtual)
irq = irq_of_parse_and_map(best_frame, 1);
else
irq = irq_of_parse_and_map(best_frame, 0);
- of_node_put(best_frame);
+
if (!irq) {
pr_err("arch_timer: Frame missing %s irq",
arch_timer_mem_use_virtual ? "virt" : "phys");
- return;
+ goto out;
}
arch_timer_detect_rate(base, np);
arch_timer_mem_register(base, irq);
arch_timer_common_init();
+out:
+ iounmap(cntctlbase);
+ of_node_put(best_frame);
}
CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
arch_timer_mem_init);