Add provision to extend CPU operations at more levels
Various CPU drivers in ARM Trusted Firmware register functions to handle
power-down operations. At present, separate functions are registered to
power down individual cores and clusters.
This scheme operates on the basis of core and cluster, and doesn't cater
for extending the hierarchy for power-down operations. For example,
future CPUs might support multiple threads which might need powering
down individually.
This patch therefore reworks the CPU operations framework to allow for
registering power down handlers on specific level basis. Henceforth:
- Generic code invokes CPU power down operations by the level
required.
- CPU drivers explicitly mention CPU_NO_RESET_FUNC when the CPU has no
reset function.
- CPU drivers register power down handlers as a list: a mandatory
handler for level 0, and optional handlers for higher levels.
All existing CPU drivers are adapted to the new CPU operations framework
without needing any functional changes within.
Also update firmware design guide.
Change-Id: I1826842d37a9e60a9e85fdcee7b4b8f6bc1ad043
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
diff --git a/lib/cpus/aarch32/aem_generic.S b/lib/cpus/aarch32/aem_generic.S
index 10ea4e4..3d6064c 100644
--- a/lib/cpus/aarch32/aem_generic.S
+++ b/lib/cpus/aarch32/aem_generic.S
@@ -65,4 +65,6 @@
endfunc aem_generic_cluster_pwr_dwn
/* cpu_ops for Base AEM FVP */
-declare_cpu_ops aem_generic, BASE_AEM_MIDR, 1
+declare_cpu_ops aem_generic, BASE_AEM_MIDR, CPU_NO_RESET_FUNC, \
+ aem_generic_core_pwr_dwn, \
+ aem_generic_cluster_pwr_dwn
diff --git a/lib/cpus/aarch32/cortex_a32.S b/lib/cpus/aarch32/cortex_a32.S
index f2b85a3..f631c4c 100644
--- a/lib/cpus/aarch32/cortex_a32.S
+++ b/lib/cpus/aarch32/cortex_a32.S
@@ -141,4 +141,7 @@
b cortex_a32_disable_smp
endfunc cortex_a32_cluster_pwr_dwn
-declare_cpu_ops cortex_a32, CORTEX_A32_MIDR
+declare_cpu_ops cortex_a32, CORTEX_A32_MIDR, \
+ cortex_a32_reset_func, \
+ cortex_a32_core_pwr_dwn, \
+ cortex_a32_cluster_pwr_dwn
diff --git a/lib/cpus/aarch32/cpu_helpers.S b/lib/cpus/aarch32/cpu_helpers.S
index a4dfe5f..900d158 100644
--- a/lib/cpus/aarch32/cpu_helpers.S
+++ b/lib/cpus/aarch32/cpu_helpers.S
@@ -70,50 +70,39 @@
#if IMAGE_BL32 /* The power down core and cluster is needed only in BL32 */
/*
- * The prepare core power down function for all platforms. After
- * the cpu_ops pointer is retrieved from cpu_data, the corresponding
- * pwr_dwn_core in the cpu_ops is invoked. Follows AAPCS.
+ * void prepare_cpu_pwr_dwn(unsigned int power_level)
+ *
+ * Prepare CPU power down function for all platforms. The function takes
+ * a domain level to be powered down as its parameter. After the cpu_ops
+ * pointer is retrieved from cpu_data, the handler for requested power
+ * level is called.
*/
- .globl prepare_core_pwr_dwn
-func prepare_core_pwr_dwn
- /* r12 is pushed to meet the 8 byte stack alignment requirement */
- push {r12, lr}
- bl _cpu_data
- pop {r12, lr}
-
- ldr r1, [r0, #CPU_DATA_CPU_OPS_PTR]
-#if ASM_ASSERTION
- cmp r1, #0
- ASM_ASSERT(ne)
-#endif
-
- /* Get the cpu_ops core_pwr_dwn handler */
- ldr r0, [r1, #CPU_PWR_DWN_CORE]
- bx r0
-endfunc prepare_core_pwr_dwn
-
+ .globl prepare_cpu_pwr_dwn
+func prepare_cpu_pwr_dwn
/*
- * The prepare cluster power down function for all platforms. After
- * the cpu_ops pointer is retrieved from cpu_data, the corresponding
- * pwr_dwn_cluster in the cpu_ops is invoked. Follows AAPCS.
+ * If the given power level exceeds CPU_MAX_PWR_DWN_OPS, we call the
+ * power down handler for the last power level
*/
- .globl prepare_cluster_pwr_dwn
-func prepare_cluster_pwr_dwn
- /* r12 is pushed to meet the 8 byte stack alignment requirement */
- push {r12, lr}
+ mov r2, #(CPU_MAX_PWR_DWN_OPS - 1)
+ cmp r0, r2
+ movhi r0, r2
+
+ push {r0, lr}
bl _cpu_data
- pop {r12, lr}
+ pop {r2, lr}
- ldr r1, [r0, #CPU_DATA_CPU_OPS_PTR]
+ ldr r0, [r0, #CPU_DATA_CPU_OPS_PTR]
#if ASM_ASSERTION
- cmp r1, #0
+ cmp r0, #0
ASM_ASSERT(ne)
#endif
- /* Get the cpu_ops cluster_pwr_dwn handler */
- ldr r0, [r1, #CPU_PWR_DWN_CLUSTER]
- bx r0
-endfunc prepare_cluster_pwr_dwn
+ /* Get the appropriate power down handler */
+ mov r1, #CPU_PWR_DWN_OPS
+ add r1, r1, r2, lsl #2
+ ldr r1, [r0, r1]
+ bx r1
+endfunc prepare_cpu_pwr_dwn
/*
* Initializes the cpu_ops_ptr if not already initialized