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/aarch64/cpu_helpers.S b/lib/cpus/aarch64/cpu_helpers.S
index dab933c..ec7f1dd 100644
--- a/lib/cpus/aarch64/cpu_helpers.S
+++ b/lib/cpus/aarch64/cpu_helpers.S
@@ -74,31 +74,23 @@
#if IMAGE_BL31 /* The power down core and cluster is needed only in BL31 */
/*
- * 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.
+ * 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
- mrs x1, tpidr_el3
- ldr x0, [x1, #CPU_DATA_CPU_OPS_PTR]
-#if ASM_ASSERTION
- cmp x0, #0
- ASM_ASSERT(ne)
-#endif
-
- /* Get the cpu_ops core_pwr_dwn handler */
- ldr x1, [x0, #CPU_PWR_DWN_CORE]
- br x1
-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.
+ * 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
+ mov_imm x2, (CPU_MAX_PWR_DWN_OPS - 1)
+ cmp x0, x2
+ csel x2, x2, x0, hi
+
mrs x1, tpidr_el3
ldr x0, [x1, #CPU_DATA_CPU_OPS_PTR]
#if ASM_ASSERTION
@@ -106,10 +98,12 @@
ASM_ASSERT(ne)
#endif
- /* Get the cpu_ops cluster_pwr_dwn handler */
- ldr x1, [x0, #CPU_PWR_DWN_CLUSTER]
+ /* Get the appropriate power down handler */
+ mov x1, #CPU_PWR_DWN_OPS
+ add x1, x1, x2, lsl #3
+ ldr x1, [x0, x1]
br x1
-endfunc prepare_cluster_pwr_dwn
+endfunc prepare_cpu_pwr_dwn
/*