ARM: hw_breakpoint: add initial Cortex-A15 (debug v7.1) support

This patch adds initial support for Cortex-A15 (debug architecture v7.1)
to the hw_breakpoint ARM backend.

Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm/include/asm/hw_breakpoint.h b/arch/arm/include/asm/hw_breakpoint.h
index f389b27..0ac141a 100644 (file)
--- a/arch/arm/include/asm/hw_breakpoint.h
+++ b/arch/arm/include/asm/hw_breakpoint.h
@@ -50,6 +50,7 @@ static inline void decode_ctrl_reg(u32 reg,
 #define ARM_DEBUG_ARCH_V6_1    2
 #define ARM_DEBUG_ARCH_V7_ECP14        3
 #define ARM_DEBUG_ARCH_V7_MM   4
+#define ARM_DEBUG_ARCH_V7_1    5
 
 /* Breakpoint */
 #define ARM_BREAKPOINT_EXECUTE 0

diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index a927ca1..b6ddbfa 100644 (file)
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -154,7 +154,10 @@ u8 arch_get_debug_arch(void)
 static int debug_arch_supported(void)
 {
        u8 arch = get_debug_arch();
-       return arch >= ARM_DEBUG_ARCH_V6 && arch <= ARM_DEBUG_ARCH_V7_ECP14;
+
+       /* We don't support the memory-mapped interface. */
+       return (arch >= ARM_DEBUG_ARCH_V6 && arch <= ARM_DEBUG_ARCH_V7_ECP14) ||
+               arch >= ARM_DEBUG_ARCH_V7_1;
 }
 
 /* Determine number of BRP register available. */
@@ -255,6 +258,7 @@ static int enable_monitor_mode(void)
                ARM_DBG_WRITE(c1, 0, (dscr | ARM_DSCR_MDBGEN));
                break;
        case ARM_DEBUG_ARCH_V7_ECP14:
+       case ARM_DEBUG_ARCH_V7_1:
                ARM_DBG_WRITE(c2, 2, (dscr | ARM_DSCR_MDBGEN));
                break;
        default:
@@ -836,7 +840,7 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
  */
 static void reset_ctrl_regs(void *info)
 {
-       int i, cpu = smp_processor_id();
+       int i, err = 0, cpu = smp_processor_id();
        u32 dbg_power;
        cpumask_t *cpumask = info;
 
@@ -848,33 +852,46 @@ static void reset_ctrl_regs(void *info)
         * Access Register to avoid taking undefined instruction exceptions
         * later on.
         */
-       if (debug_arch >= ARM_DEBUG_ARCH_V7_ECP14) {
+       switch (debug_arch) {
+       case 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;
-               }
-
+               if ((dbg_power & 0x1) == 0)
+                       err = -EPERM;
+               break;
+       case ARM_DEBUG_ARCH_V7_1:
                /*
-                * Unconditionally clear the lock by writing a value
-                * other than 0xC5ACCE55 to the access register.
+                * Ensure the OS double lock is clear.
                 */
-               asm volatile("mcr p14, 0, %0, c1, c0, 4" : : "r" (0));
-               isb();
+               asm volatile("mrc p14, 0, %0, c1, c3, 4" : "=r" (dbg_power));
+               if ((dbg_power & 0x1) == 1)
+                       err = -EPERM;
+               break;
+       }
 
-               /*
-                * Clear any configured vector-catch events before
-                * enabling monitor mode.
-                */
-               asm volatile("mcr p14, 0, %0, c0, c7, 0" : : "r" (0));
-               isb();
+       if (err) {
+               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.
+        */
+       asm volatile("mcr p14, 0, %0, c1, c0, 4" : : "r" (0));
+       isb();
+
+       /*
+        * Clear any configured vector-catch events before
+        * enabling monitor mode.
+        */
+       asm volatile("mcr p14, 0, %0, c0, c7, 0" : : "r" (0));
+       isb();
+
        if (enable_monitor_mode())
                return;