[PATCH 09/17] firmware: qcom_scm-64: Improve SMC convention detection

Elliot Berman
2019-11-05T01:28:07Z

- Use enum to describe SMC convention.
- Improve SMC convention detection to use __qcom_scm_is_call_available
instead of circumventing qcom_scm_call_smccc.
- Improve SMC convention detection to check that SMCCC-32 works, instead
of just assuming it does of SMCCC-64 does not.

Signed-off-by: Elliot Berman <eberman@codeaurora.org>
---
drivers/firmware/qcom_scm-64.c | 42 ++++++++++++++++++++++++------------------
1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/drivers/firmware/qcom_scm-64.c b/drivers/firmware/qcom_scm-64.c
index f79b0dc..2579246 100644
--- a/drivers/firmware/qcom_scm-64.c
+++ b/drivers/firmware/qcom_scm-64.c
@@ -58,7 +58,13 @@ struct arm_smccc_args {
unsigned long a[8];
};

-static u64 qcom_smccc_convention = -1;
+enum qcom_smc_convention {
+ SMC_CONVENTION_UNKNOWN,
+ SMC_CONVENTION_ARM_32,
+ SMC_CONVENTION_ARM_64,
+};
+
+static enum qcom_smc_convention qcom_smc_convention = SMC_CONVENTION_UNKNOWN;
static DEFINE_MUTEX(qcom_scm_lock);

#define QCOM_SCM_EBUSY_WAIT_MS 30
@@ -103,7 +109,9 @@ static int ___qcom_scm_call_smccc(struct device *dev,

smc.a[0] = ARM_SMCCC_CALL_VAL(
atomic ? ARM_SMCCC_FAST_CALL : ARM_SMCCC_STD_CALL,
- qcom_smccc_convention,
+ (qcom_smc_convention == SMC_CONVENTION_ARM_64) ?
+ ARM_SMCCC_SMC_64 :
+ ARM_SMCCC_SMC_32,
desc->owner,
SMCCC_FUNCNUM(desc->svc, desc->cmd));
smc.a[1] = desc->arginfo;
@@ -117,7 +125,7 @@ static int ___qcom_scm_call_smccc(struct device *dev,
if (!args_virt)
return -ENOMEM;

- if (qcom_smccc_convention == ARM_SMCCC_SMC_32) {
+ if (qcom_smc_convention == SMC_CONVENTION_ARM_32) {
__le32 *args = args_virt;

for (i = 0; i < SMCCC_N_EXT_ARGS; i++)
@@ -583,19 +591,17 @@ int __qcom_scm_qsmmu500_wait_safe_toggle(struct device *dev, bool en)

void __qcom_scm_init(void)
{
- u64 cmd;
- struct arm_smccc_res res;
- u32 function = SMCCC_FUNCNUM(QCOM_SCM_SVC_INFO, QCOM_SCM_INFO_IS_CALL_AVAIL);
-
- /* First try a SMC64 call */
- cmd = ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64,
- ARM_SMCCC_OWNER_SIP, function);
-
- arm_smccc_smc(cmd, QCOM_SCM_ARGS(1), cmd & (~BIT(ARM_SMCCC_TYPE_SHIFT)),
- 0, 0, 0, 0, 0, &res);
-
- if (!res.a0 && res.a1)
- qcom_smccc_convention = ARM_SMCCC_SMC_64;
- else
- qcom_smccc_convention = ARM_SMCCC_SMC_32;
+ qcom_smc_convention = SMC_CONVENTION_ARM_64;
+ if (__qcom_scm_is_call_available(NULL, QCOM_SCM_SVC_INFO,
+ QCOM_SCM_INFO_IS_CALL_AVAIL) == 1)
+ goto out;
+
+ qcom_smc_convention = SMC_CONVENTION_ARM_32;
+ if (__qcom_scm_is_call_available(NULL, QCOM_SCM_SVC_INFO,
+ QCOM_SCM_INFO_IS_CALL_AVAIL) == 1)
+ goto out;
+
+ qcom_smc_convention = SMC_CONVENTION_UNKNOWN;
+out:
+ pr_debug("QCOM SCM SMC Convention: %d\n", qcom_smc_convention);