| Message ID | 20220115162703.699347-3-henrik@grimler.se (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add initial support for exynos5420-chagallwifi | expand |
diff --git a/arch/arm/mach-exynos/firmware.c b/arch/arm/mach-exynos/firmware.c index 2eaf2dbb8e81..2da5b60b59e2 100644 --- a/arch/arm/mach-exynos/firmware.c +++ b/arch/arm/mach-exynos/firmware.c @@ -60,8 +60,10 @@ static int exynos_cpu_boot(int cpu) /* * Exynos3250 doesn't need to send smc command for secondary CPU boot * because Exynos3250 removes WFE in secure mode. + * + * On Exynos5 devices the call is ignored by trustzone firmware. */ - if (soc_is_exynos3250()) + if (!soc_is_exynos4210() && !soc_is_exynos4412()) return 0; /*
On Exynos5 the call is simply ignored by most variants of the trustzone firmware. However, on some devices it instead causes the device to hang, so let's avoid the call for the SoCs where it should not be needed. To see that the call is ignored, we can look into sboot/tzsw. On most of the Exynos{4,5} devices the part of sboot/tzsw that seem to handle the secure monitor calls is quite easy to recognise, the SMC number is compared to known ones, and if equal it branches to the relevant function. In assembly this looks something like: ;-- handle_smc: 0x00000514 650070e3 cmn r0, 0x65 0x00000518 0a00000a beq loc.smc_cmd_reg 0x0000051c 010070e3 cmn r0, 1 0x00000520 6c00000a beq loc.smc_cmd_init 0x00000524 020070e3 cmn r0, 2 0x00000528 6b00000a beq loc.smc_cmd_info 0x0000052c 030070e3 cmn r0, 3 0x00000530 6e00000a beq loc.smc_cmd_sleep 0x00000534 060070e3 cmn r0, 6 0x00000538 ae00000a beq loc.smc_cmd_save_state 0x0000053c 070070e3 cmn r0, 7 0x00000540 b400000a beq loc.smc_cmd_standby 0x00000544 2b01001a bne loc.smc_return_minus1 where above example is from exynos5420-arndale-octa. As can be seen the case where r0 is 4 (i.e. SMC_CMD_CPU1BOOT) is not handled. The annotations are taken from github.com/hsnaves/exynos5410-firmware, where a large part of the exynos5410 trustzone firmware has been reverse-engineered. Signed-off-by: Henrik Grimler <henrik@grimler.se> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> --- Sent previously as RFC --- arch/arm/mach-exynos/firmware.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)