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authorWill Deacon <will.deacon@arm.com>2011-02-25 20:20:42 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-02-26 13:35:51 +0000
commitc09bae709182046ab104757115dfbd74a1ba1a15 (patch)
tree4abb05c23dd1846666c327d4ccb8aa3458b6f44a
parentba55d3db9bb59a52fe45dbc5d62776adbb289e54 (diff)
ARM: 6768/1: hw_breakpoint: ensure debug logic is powered up on v7 cores
ARMv7 allows the debug core logic to be powered down and provides the DBGPRSR register so that software can power-up and check the status of the logic. This patch ensures that the debug logic is powered up on ARMv7 cores before we attempt to access the extended debug registers. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/kernel/hw_breakpoint.c26
1 files changed, 23 insertions, 3 deletions
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index d600bd350704..44b84fe6e1b0 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -836,9 +836,11 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
/*
* One-time initialisation.
*/
-static void reset_ctrl_regs(void *unused)
+static void reset_ctrl_regs(void *info)
{
- int i;
+ int i, cpu = smp_processor_id();
+ u32 dbg_power;
+ cpumask_t *cpumask = info;
/*
* v7 debug contains save and restore registers so that debug state
@@ -850,6 +852,17 @@ static void reset_ctrl_regs(void *unused)
*/
if (debug_arch >= ARM_DEBUG_ARCH_V7_ECP14) {
/*
+ * Ensure sticky power-down is clear (i.e. debug logic is
+ * powered up).
+ */
+ asm volatile("mrc p14, 0, %0, c1, c5, 4" : "=r" (dbg_power));
+ if ((dbg_power & 0x1) == 0) {
+ pr_warning("CPU %d debug is powered down!\n", cpu);
+ cpumask_or(cpumask, cpumask, cpumask_of(cpu));
+ return;
+ }
+
+ /*
* Unconditionally clear the lock by writing a value
* other than 0xC5ACCE55 to the access register.
*/
@@ -887,6 +900,7 @@ static struct notifier_block __cpuinitdata dbg_reset_nb = {
static int __init arch_hw_breakpoint_init(void)
{
u32 dscr;
+ cpumask_t cpumask = { CPU_BITS_NONE };
debug_arch = get_debug_arch();
@@ -911,7 +925,13 @@ static int __init arch_hw_breakpoint_init(void)
* Reset the breakpoint resources. We assume that a halting
* debugger will leave the world in a nice state for us.
*/
- on_each_cpu(reset_ctrl_regs, NULL, 1);
+ on_each_cpu(reset_ctrl_regs, &cpumask, 1);
+ if (!cpumask_empty(&cpumask)) {
+ core_num_brps = 0;
+ core_num_reserved_brps = 0;
+ core_num_wrps = 0;
+ return 0;
+ }
ARM_DBG_READ(c1, 0, dscr);
if (dscr & ARM_DSCR_HDBGEN) {