[PATCH-v3 6/7] bsp/sparc: Ensure that data cache snooping is enabled

[Daniel Cederman]

Check that data cache snooping exists and is enabled on all cores.
---
 c/src/lib/libbsp/shared/include/fatal.h       |    2 ++
 c/src/lib/libbsp/sparc/leon3/include/leon.h   |   10 ++++++++++
 c/src/lib/libbsp/sparc/leon3/startup/bspsmp.c |   14 ++++++++++++--
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/c/src/lib/libbsp/shared/include/fatal.h b/c/src/lib/libbsp/shared/include/fatal.h
index e928bba..99da207 100644
--- a/c/src/lib/libbsp/shared/include/fatal.h
+++ b/c/src/lib/libbsp/shared/include/fatal.h
@@ -49,6 +49,8 @@ typedef enum {
   /* LEON3 fatal codes */
   LEON3_FATAL_NO_IRQMP_CONTROLLER = BSP_FATAL_CODE_BLOCK(2),
   LEON3_FATAL_CONSOLE_REGISTER_DEV,
+  LEON3_FATAL_INVALID_CACHE_CONFIG_MAIN_PROCESSOR,
+  LEON3_FATAL_INVALID_CACHE_CONFIG_SECONDARY_PROCESSOR,
 
   /* LPC24XX fatal codes */
   LPC24XX_FATAL_PL111_SET_UP = BSP_FATAL_CODE_BLOCK(3),
diff --git a/c/src/lib/libbsp/sparc/leon3/include/leon.h b/c/src/lib/libbsp/sparc/leon3/include/leon.h
index d7048f3..a62ad29 100644
--- a/c/src/lib/libbsp/sparc/leon3/include/leon.h
+++ b/c/src/lib/libbsp/sparc/leon3/include/leon.h
@@ -86,6 +86,11 @@ extern "C" {
 #define LEON_REG_TIMER_CONTROL_LD    0x00000004  /* 1 = load counter */
                                               /* 0 = no function */
 
+/*
+ *  The following defines the bits in the LEON Cache Control Register.
+ */
+#define LEON3_REG_CACHE_CTRL_DS      0x00800000 /* Data cache snooping */
+
 /* LEON3 Interrupt Controller */
 extern volatile struct irqmp_regs *LEON3_IrqCtrl_Regs;
 /* LEON3 GP Timer */
@@ -347,6 +352,11 @@ static inline uint32_t leon3_get_cache_control_register(void)
   return leon3_get_system_register(0x0);
 }
 
+static inline bool leon3_data_cache_snooping_enabled(void)
+{
+  return leon3_get_cache_control_register() & LEON3_REG_CACHE_CTRL_DS;
+}
+
 static inline uint32_t leon3_get_inst_cache_config_register(void)
 {
   return leon3_get_system_register(0x8);
diff --git a/c/src/lib/libbsp/sparc/leon3/startup/bspsmp.c b/c/src/lib/libbsp/sparc/leon3/startup/bspsmp.c
index 9166ad5..644992f 100644
--- a/c/src/lib/libbsp/sparc/leon3/startup/bspsmp.c
+++ b/c/src/lib/libbsp/sparc/leon3/startup/bspsmp.c
@@ -15,6 +15,7 @@
 
 #include <bsp.h>
 #include <bsp/bootcard.h>
+#include <bsp/fatal.h>
 #include <cache_.h>
 #include <leon.h>
 #include <rtems/bspIo.h>
@@ -39,7 +40,15 @@ void bsp_start_on_secondary_processor()
 {
   uint32_t cpu_index_self = _CPU_SMP_Get_current_processor();
 
-  leon3_set_cache_control_register(0x80000F);
+  /*
+   * If data cache snooping is not enabled we terminate using
+   * BSP_fatal_exit instead of bsp_fatal. This is done since
+   * the latter function tries to acquire a ticket lock, an
+   * operation which requires data cache snooping to be enabled.
+   */
+  if ( ! leon3_data_cache_snooping_enabled() )
+    BSP_fatal_exit( LEON3_FATAL_INVALID_CACHE_CONFIG_SECONDARY_PROCESSOR );
+
   /* Unmask IPI interrupts at Interrupt controller for this CPU */
   LEON3_IrqCtrl_Regs->mask[cpu_index_self] |= 1U << LEON3_MP_IRQ;
 
@@ -48,7 +57,8 @@ void bsp_start_on_secondary_processor()
 
 uint32_t _CPU_SMP_Initialize( void )
 {
-  leon3_set_cache_control_register(0x80000F);
+  if ( ! leon3_data_cache_snooping_enabled() )
+    bsp_fatal( LEON3_FATAL_INVALID_CACHE_CONFIG_MAIN_PROCESSOR );
 
   if ( rtems_configuration_get_maximum_processors() > 1 ) {
     LEON_Unmask_interrupt(LEON3_MP_IRQ);
-- 
1.7.9.5