adafruit-mirror/zephyr
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 8

arch: arm: cortex_m: pm_s2ram: wrap context save/restore in macros

Browse source 
Wrap the CPU register save/restore operations (GPR and special registers)
in macros to make core logic simpler to follow. This is also a preparatory
step to introduce ARMv6-M and ARMv7-M support.

Signed-off-by: Mathieu Choplain <mathieu.choplain@st.com>
This commit is contained in:
Mathieu Choplain 2024-11-04 13:55:25 +01:00 committed by Anas Nashif
parent 041714cb37
commit 18f41aa63c
1 changed files with 62 additions and 34 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

96
arch/arm/core/cortex_m/pm_s2ram.S
View file

@ -38,6 +38,63 @@
ldr tmp_reg, [cpu_ctx_reg, # CPU_CTX_SR_OFFSET(sr_name)]; \
msr sr_name, tmp_reg;
/*
* The following macros could be written as assembler macros, but C is used
* for portability (assembler macro syntax may differ between toolchains).
*/
/*
* Pushes registers r4~r12 and lr on the stack.
* r0 is unmodified but other GPRs may be overwritten.
*/
#define PUSH_GPRS \
push {r4-r12, lr}
/*
* Pops registers r4~r12 and lr from the stack
* r0 is unmodified but other GPRs may be overwritten.
*/
#define POP_GPRS \
pop {r4-r12, lr}
/*
* Saves the CPU's special registers in the `struct __cpu_context`
* pointed to by the `cpu_ctx` register.
* The `tmp_reg` register is overwritten as part of this process.
*/
#define SAVE_SPECIAL_REGISTERS(cpu_ctx, tmp_reg) \
SAVE_SPECIAL_REG(msp, cpu_ctx, tmp_reg) \
SAVE_SPECIAL_REG(msplim, cpu_ctx, tmp_reg) \
SAVE_SPECIAL_REG(psp, cpu_ctx, tmp_reg) \
SAVE_SPECIAL_REG(psplim, cpu_ctx, tmp_reg) \
SAVE_SPECIAL_REG(primask, cpu_ctx, tmp_reg) \
SAVE_SPECIAL_REG(faultmask, cpu_ctx, tmp_reg) \
SAVE_SPECIAL_REG(basepri, cpu_ctx, tmp_reg) \
SAVE_SPECIAL_REG(control, cpu_ctx, tmp_reg)
/*
* Restores the CPU's special registers from the `struct __cpu_context`
* pointed to by the `cpu_ctx` register.
* The `tmp_reg` register is overwritten as part of this process.
*
* N.B.: ISB at the end is required because "Software must use an ISB
* barrier instruction to ensure a write to the CONTROL register takes
* effect before the next instruction is executed."
*
* If this macro is modified, make sure CONTROL is always the last
* restored register, and that an ISB follows the MSR instruction.
*/
#define RESTORE_SPECIAL_REGISTERS(cpu_ctx, tmp_reg) \
RESTORE_SPECIAL_REG(msp, cpu_ctx, tmp_reg) \
RESTORE_SPECIAL_REG(msplim, cpu_ctx, tmp_reg) \
RESTORE_SPECIAL_REG(psp, cpu_ctx, tmp_reg) \
RESTORE_SPECIAL_REG(psplim, cpu_ctx, tmp_reg) \
RESTORE_SPECIAL_REG(primask, cpu_ctx, tmp_reg) \
RESTORE_SPECIAL_REG(faultmask, cpu_ctx, tmp_reg) \
RESTORE_SPECIAL_REG(basepri, cpu_ctx, tmp_reg) \
RESTORE_SPECIAL_REG(control, cpu_ctx, tmp_reg) \
isb
_ASM_FILE_PROLOGUE
GTEXT(pm_s2ram_mark_set)
@ -50,7 +107,7 @@ SECTION_FUNC(TEXT, arch_pm_s2ram_suspend)
*
* r0: address of the system_off function
*/
push {r4-r12, lr}
PUSH_GPRS
/* Move system_off to protected register. */
mov r4, r0
@ -58,21 +115,7 @@ SECTION_FUNC(TEXT, arch_pm_s2ram_suspend)
/* Store CPU context */
ldr r1, =_cpu_context
SAVE_SPECIAL_REG(msp, r1, r2)
SAVE_SPECIAL_REG(msplim, r1, r2)
SAVE_SPECIAL_REG(psp, r1, r2)
SAVE_SPECIAL_REG(psplim, r1, r2)
SAVE_SPECIAL_REG(primask, r1, r2)
SAVE_SPECIAL_REG(faultmask, r1, r2)
SAVE_SPECIAL_REG(basepri, r1, r2)
SAVE_SPECIAL_REG(control, r1, r2)
SAVE_SPECIAL_REGISTERS(/* ctx: */ r1, /* tmp: */ r2)
/*
* Mark entering suspend to RAM.
@ -102,7 +145,7 @@ SECTION_FUNC(TEXT, arch_pm_s2ram_suspend)
/* Move system_off back to r0 as return value */
mov r0, r4
pop {r4-r12, lr}
POP_GPRS
bx lr
@ -124,24 +167,9 @@ resume:
*/
ldr r0, =_cpu_context
RESTORE_SPECIAL_REG(msp, r0, r1)
RESTORE_SPECIAL_REGISTERS(/* ctx: */ r0, /* tmp: */ r1)
RESTORE_SPECIAL_REG(msplim, r0, r1)
RESTORE_SPECIAL_REG(psp, r0, r1)
RESTORE_SPECIAL_REG(psplim, r0, r1)
RESTORE_SPECIAL_REG(primask, r0, r1)
RESTORE_SPECIAL_REG(faultmask, r0, r1)
RESTORE_SPECIAL_REG(basepri, r0, r1)
RESTORE_SPECIAL_REG(control, r0, r1)
isb
pop {r4-r12, lr}
POP_GPRS
/*
* Set the return value and return