firmware: qcom: scm: Fix interrupted SCM calls

[ Upstream commit 82bcd087029f6056506ea929f11af02622230901 ]

This patch adds a Qualcomm specific quirk to the arm_smccc_smc call.

On Qualcomm ARM64 platforms, the SMC call can return before it has
completed.  If this occurs, the call can be restarted, but it requires
using the returned session ID value from the interrupted SMC call.

The quirk stores off the session ID from the interrupted call in the
quirk structure so that it can be used by the caller.

This patch folds in a fix given by Sricharan R:
https://lkml.org/lkml/2016/9/28/272

Signed-off-by: Andy Gross <andy.gross@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 10 insertions, 3 deletions

diff --git a/drivers/firmware/qcom_scm-64.c b/drivers/firmware/qcom_scm-64.c
index 4a0f5ead4fb5..1e2e5198db53 100644
--- a/drivers/firmware/qcom_scm-64.c
+++ b/drivers/firmware/qcom_scm-64.c
@@ -91,6 +91,7 @@ static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
         dma_addr_t args_phys = 0;
         void *args_virt = NULL;
         size_t alloc_len;
+        struct arm_smccc_quirk quirk = {.id = ARM_SMCCC_QUIRK_QCOM_A6};
 
         if (unlikely(arglen > N_REGISTER_ARGS)) {
                 alloc_len = N_EXT_QCOM_SCM_ARGS * sizeof(u64);
@@ -131,10 +132,16 @@ static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
                                          qcom_smccc_convention,
                                          ARM_SMCCC_OWNER_SIP, fn_id);
 
+                quirk.state.a6 = 0;
+
                 do {
-                        arm_smccc_smc(cmd, desc->arginfo, desc->args[0],
-                                      desc->args[1], desc->args[2], x5, 0, 0,
-                                      res);
+                        arm_smccc_smc_quirk(cmd, desc->arginfo, desc->args[0],
+                                      desc->args[1], desc->args[2], x5,
+                                      quirk.state.a6, 0, res, &quirk);
+
+                        if (res->a0 == QCOM_SCM_INTERRUPTED)
+                                cmd = res->a0;
+
                 } while (res->a0 == QCOM_SCM_INTERRUPTED);
 
                 mutex_unlock(&qcom_scm_lock);