diff options
author | Robin Murphy <robin.murphy@arm.com> | 2016-02-01 12:00:48 +0000 |
---|---|---|
committer | Daniel Lezcano <daniel.lezcano@linaro.org> | 2016-02-25 14:30:15 +0100 |
commit | e392d603f61767cb2de4d82bb55a035918f8342c (patch) | |
tree | 1051148f6bec4a0bea199d2302858621a9ce9c5d | |
parent | bbf66d897adf2bb0c310db96c97e8db6369f39e1 (diff) |
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>
-rw-r--r-- | drivers/clocksource/arm_arch_timer.c | 36 |
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); |