diff mbox series

[v4,1/3] firmware: qcom_scm-64: Add atomic version of qcom_scm_call

Message ID 20190823063248.13295-2-vivek.gautam@codeaurora.org (mailing list archive)
State New, archived
Headers show
Series Qcom smmu-500 wait-for-safe handling for sdm845 | expand

Commit Message

Vivek Gautam Aug. 23, 2019, 6:32 a.m. UTC 
There are scnenarios where drivers are required to make a
scm call in atomic context, such as in one of the qcom's
arm-smmu-500 errata [1].

[1] ("https://source.codeaurora.org/quic/la/kernel/msm-4.9/
      tree/drivers/iommu/arm-smmu.c?h=msm-4.9#n4842")

Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 drivers/firmware/qcom_scm-64.c | 136 ++++++++++++++++++++++++++++-------------
 1 file changed, 92 insertions(+), 44 deletions(-)

Comments

Stephen Boyd Sept. 6, 2019, 3:12 p.m. UTC | #1 
Quoting Vivek Gautam (2019-08-22 23:32:46)
> There are scnenarios where drivers are required to make a
> scm call in atomic context, such as in one of the qcom's
> arm-smmu-500 errata [1].
> 
> [1] ("https://source.codeaurora.org/quic/la/kernel/msm-4.9/
>       tree/drivers/iommu/arm-smmu.c?h=msm-4.9#n4842")
> 
> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>  drivers/firmware/qcom_scm-64.c | 136 ++++++++++++++++++++++++++++-------------
>  1 file changed, 92 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/firmware/qcom_scm-64.c b/drivers/firmware/qcom_scm-64.c
> index 91d5ad7cf58b..b6dca32c5ac4 100644
> --- a/drivers/firmware/qcom_scm-64.c
> +++ b/drivers/firmware/qcom_scm-64.c
> @@ -62,32 +62,71 @@ static DEFINE_MUTEX(qcom_scm_lock);
>  #define FIRST_EXT_ARG_IDX 3
>  #define N_REGISTER_ARGS (MAX_QCOM_SCM_ARGS - N_EXT_QCOM_SCM_ARGS + 1)
>  
> -/**
> - * qcom_scm_call() - Invoke a syscall in the secure world
> - * @dev:       device
> - * @svc_id:    service identifier
> - * @cmd_id:    command identifier
> - * @desc:      Descriptor structure containing arguments and return values
> - *
> - * Sends a command to the SCM and waits for the command to finish processing.
> - * This should *only* be called in pre-emptible context.
> -*/
> -static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
> -                        const struct qcom_scm_desc *desc,
> -                        struct arm_smccc_res *res)
> +static void __qcom_scm_call_do(const struct qcom_scm_desc *desc,
> +                              struct arm_smccc_res *res, u32 fn_id,
> +                              u64 x5, u32 type)
> +{
> +       u64 cmd;
> +       struct arm_smccc_quirk quirk = {.id = ARM_SMCCC_QUIRK_QCOM_A6};

Nitpick: Put spaces around braces please.

> +
> +       cmd = ARM_SMCCC_CALL_VAL(type, qcom_smccc_convention,
> +                                ARM_SMCCC_OWNER_SIP, fn_id);
> +
> +       quirk.state.a6 = 0;
> +
> +       do {
> +               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);
> +}
> +
> +static void qcom_scm_call_do(const struct qcom_scm_desc *desc,
> +                            struct arm_smccc_res *res, u32 fn_id,
> +                            u64 x5, bool atomic)
> +{
> +       int retry_count = 0;
> +
> +       if (!atomic) {
> +               do {
> +                       mutex_lock(&qcom_scm_lock);
> +
> +                       __qcom_scm_call_do(desc, res, fn_id, x5,
> +                                          ARM_SMCCC_STD_CALL);
> +
> +                       mutex_unlock(&qcom_scm_lock);
> +
> +                       if (res->a0 == QCOM_SCM_V2_EBUSY) {
> +                               if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY)
> +                                       break;
> +                               msleep(QCOM_SCM_EBUSY_WAIT_MS);
> +                       }
> +               }  while (res->a0 == QCOM_SCM_V2_EBUSY);
> +       } else {
> +               __qcom_scm_call_do(desc, res, fn_id, x5, ARM_SMCCC_FAST_CALL);
> +       }

To save on some indentation maybe you could write it like:

	if (atomic) {
		__qcom_scm_call_do(..)
		return;
	}

	do {
		mutex_lock(..)
		...
	} while (..);

> +}
> +
> +static int ___qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
> +                           const struct qcom_scm_desc *desc,
> +                           struct arm_smccc_res *res, bool atomic)
>  {
>         int arglen = desc->arginfo & 0xf;
> -       int retry_count = 0, i;
> +       int i;
>         u32 fn_id = QCOM_SCM_FNID(svc_id, cmd_id);
> -       u64 cmd, x5 = desc->args[FIRST_EXT_ARG_IDX];
> +       u64 x5 = desc->args[FIRST_EXT_ARG_IDX];
>         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};
> +       gfp_t flag = atomic ? GFP_ATOMIC : GFP_KERNEL;
>  
>         if (unlikely(arglen > N_REGISTER_ARGS)) {
>                 alloc_len = N_EXT_QCOM_SCM_ARGS * sizeof(u64);
> -               args_virt = kzalloc(PAGE_ALIGN(alloc_len), GFP_KERNEL);
> +               args_virt = kzalloc(PAGE_ALIGN(alloc_len), flag);
>  
>                 if (!args_virt)
>                         return -ENOMEM;
> @@ -156,6 +169,41 @@ static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
>         return 0;
>  }
>  
> +/**
> + * qcom_scm_call() - Invoke a syscall in the secure world
> + * @dev:       device
> + * @svc_id:    service identifier
> + * @cmd_id:    command identifier
> + * @desc:      Descriptor structure containing arguments and return values
> + *
> + * Sends a command to the SCM and waits for the command to finish processing.
> + * This should *only* be called in pre-emptible context.

Add a might_sleep() then?

> + */
> +static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
> +                        const struct qcom_scm_desc *desc,
> +                        struct arm_smccc_res *res)
> +{
> +       return ___qcom_scm_call(dev, svc_id, cmd_id, desc, res, false);
> +}
> +
> +/**
> + * qcom_scm_call_atomic() - atomic variation of qcom_scm_call()
> + * @dev:       device
> + * @svc_id:    service identifier
> + * @cmd_id:    command identifier
> + * @desc:      Descriptor structure containing arguments and return values
> + * @res:       Structure containing results from SMC/HVC call
> + *
> + * Sends a command to the SCM and waits for the command to finish processing.
> + * This should be called in atomic context only.
 
Maybe add a cant_sleep()?

> + */
> +static int qcom_scm_call_atomic(struct device *dev, u32 svc_id, u32 cmd_id,
> +                               const struct qcom_scm_desc *desc,
> +                               struct arm_smccc_res *res)
> +{
> +       return ___qcom_scm_call(dev, svc_id, cmd_id, desc, res, true);
> +}
> +
Sai Prakash Ranjan Sept. 16, 2019, 9:48 a.m. UTC | #2 
Hi Stephen,

On 2019-09-06 20:42, Stephen Boyd wrote:
> Quoting Vivek Gautam (2019-08-22 23:32:46)
>> There are scnenarios where drivers are required to make a
>> scm call in atomic context, such as in one of the qcom's
>> arm-smmu-500 errata [1].
>> 
>> [1] ("https://source.codeaurora.org/quic/la/kernel/msm-4.9/
>>       tree/drivers/iommu/arm-smmu.c?h=msm-4.9#n4842")
>> 
>> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
>> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
>> ---
>>  drivers/firmware/qcom_scm-64.c | 136 
>> ++++++++++++++++++++++++++++-------------
>>  1 file changed, 92 insertions(+), 44 deletions(-)
>> 
>> diff --git a/drivers/firmware/qcom_scm-64.c 
>> b/drivers/firmware/qcom_scm-64.c
>> index 91d5ad7cf58b..b6dca32c5ac4 100644
>> --- a/drivers/firmware/qcom_scm-64.c
>> +++ b/drivers/firmware/qcom_scm-64.c
>> @@ -62,32 +62,71 @@ static DEFINE_MUTEX(qcom_scm_lock);
>>  #define FIRST_EXT_ARG_IDX 3
>>  #define N_REGISTER_ARGS (MAX_QCOM_SCM_ARGS - N_EXT_QCOM_SCM_ARGS + 1)
>> 
>> -/**
>> - * qcom_scm_call() - Invoke a syscall in the secure world
>> - * @dev:       device
>> - * @svc_id:    service identifier
>> - * @cmd_id:    command identifier
>> - * @desc:      Descriptor structure containing arguments and return 
>> values
>> - *
>> - * Sends a command to the SCM and waits for the command to finish 
>> processing.
>> - * This should *only* be called in pre-emptible context.
>> -*/
>> -static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
>> -                        const struct qcom_scm_desc *desc,
>> -                        struct arm_smccc_res *res)
>> +static void __qcom_scm_call_do(const struct qcom_scm_desc *desc,
>> +                              struct arm_smccc_res *res, u32 fn_id,
>> +                              u64 x5, u32 type)
>> +{
>> +       u64 cmd;
>> +       struct arm_smccc_quirk quirk = {.id = 
>> ARM_SMCCC_QUIRK_QCOM_A6};
> 
> Nitpick: Put spaces around braces please.
> 
>> +
>> +       cmd = ARM_SMCCC_CALL_VAL(type, qcom_smccc_convention,
>> +                                ARM_SMCCC_OWNER_SIP, fn_id);
>> +
>> +       quirk.state.a6 = 0;
>> +
>> +       do {
>> +               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);
>> +}
>> +
>> +static void qcom_scm_call_do(const struct qcom_scm_desc *desc,
>> +                            struct arm_smccc_res *res, u32 fn_id,
>> +                            u64 x5, bool atomic)
>> +{
>> +       int retry_count = 0;
>> +
>> +       if (!atomic) {
>> +               do {
>> +                       mutex_lock(&qcom_scm_lock);
>> +
>> +                       __qcom_scm_call_do(desc, res, fn_id, x5,
>> +                                          ARM_SMCCC_STD_CALL);
>> +
>> +                       mutex_unlock(&qcom_scm_lock);
>> +
>> +                       if (res->a0 == QCOM_SCM_V2_EBUSY) {
>> +                               if (retry_count++ > 
>> QCOM_SCM_EBUSY_MAX_RETRY)
>> +                                       break;
>> +                               msleep(QCOM_SCM_EBUSY_WAIT_MS);
>> +                       }
>> +               }  while (res->a0 == QCOM_SCM_V2_EBUSY);
>> +       } else {
>> +               __qcom_scm_call_do(desc, res, fn_id, x5, 
>> ARM_SMCCC_FAST_CALL);
>> +       }
> 
> To save on some indentation maybe you could write it like:
> 
> 	if (atomic) {
> 		__qcom_scm_call_do(..)
> 		return;
> 	}
> 
> 	do {
> 		mutex_lock(..)
> 		...
> 	} while (..);
> 
>> +}
>> +
>> +static int ___qcom_scm_call(struct device *dev, u32 svc_id, u32 
>> cmd_id,
>> +                           const struct qcom_scm_desc *desc,
>> +                           struct arm_smccc_res *res, bool atomic)
>>  {
>>         int arglen = desc->arginfo & 0xf;
>> -       int retry_count = 0, i;
>> +       int i;
>>         u32 fn_id = QCOM_SCM_FNID(svc_id, cmd_id);
>> -       u64 cmd, x5 = desc->args[FIRST_EXT_ARG_IDX];
>> +       u64 x5 = desc->args[FIRST_EXT_ARG_IDX];
>>         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};
>> +       gfp_t flag = atomic ? GFP_ATOMIC : GFP_KERNEL;
>> 
>>         if (unlikely(arglen > N_REGISTER_ARGS)) {
>>                 alloc_len = N_EXT_QCOM_SCM_ARGS * sizeof(u64);
>> -               args_virt = kzalloc(PAGE_ALIGN(alloc_len), 
>> GFP_KERNEL);
>> +               args_virt = kzalloc(PAGE_ALIGN(alloc_len), flag);
>> 
>>                 if (!args_virt)
>>                         return -ENOMEM;
>> @@ -156,6 +169,41 @@ static int qcom_scm_call(struct device *dev, u32 
>> svc_id, u32 cmd_id,
>>         return 0;
>>  }
>> 
>> +/**
>> + * qcom_scm_call() - Invoke a syscall in the secure world
>> + * @dev:       device
>> + * @svc_id:    service identifier
>> + * @cmd_id:    command identifier
>> + * @desc:      Descriptor structure containing arguments and return 
>> values
>> + *
>> + * Sends a command to the SCM and waits for the command to finish 
>> processing.
>> + * This should *only* be called in pre-emptible context.
> 
> Add a might_sleep() then?
> 
>> + */
>> +static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
>> +                        const struct qcom_scm_desc *desc,
>> +                        struct arm_smccc_res *res)
>> +{
>> +       return ___qcom_scm_call(dev, svc_id, cmd_id, desc, res, 
>> false);
>> +}
>> +
>> +/**
>> + * qcom_scm_call_atomic() - atomic variation of qcom_scm_call()
>> + * @dev:       device
>> + * @svc_id:    service identifier
>> + * @cmd_id:    command identifier
>> + * @desc:      Descriptor structure containing arguments and return 
>> values
>> + * @res:       Structure containing results from SMC/HVC call
>> + *
>> + * Sends a command to the SCM and waits for the command to finish 
>> processing.
>> + * This should be called in atomic context only.
> 
> Maybe add a cant_sleep()?
> 
>> + */
>> +static int qcom_scm_call_atomic(struct device *dev, u32 svc_id, u32 
>> cmd_id,
>> +                               const struct qcom_scm_desc *desc,
>> +                               struct arm_smccc_res *res)
>> +{
>> +       return ___qcom_scm_call(dev, svc_id, cmd_id, desc, res, true);
>> +}
>> +

Have addressed all your comments in v5.

Thanks,
Sai
diff mbox series

Patch

diff --git a/drivers/firmware/qcom_scm-64.c b/drivers/firmware/qcom_scm-64.c
index 91d5ad7cf58b..b6dca32c5ac4 100644
--- a/drivers/firmware/qcom_scm-64.c
+++ b/drivers/firmware/qcom_scm-64.c
@@ -62,32 +62,71 @@  static DEFINE_MUTEX(qcom_scm_lock);
 #define FIRST_EXT_ARG_IDX 3
 #define N_REGISTER_ARGS (MAX_QCOM_SCM_ARGS - N_EXT_QCOM_SCM_ARGS + 1)
 
-/**
- * qcom_scm_call() - Invoke a syscall in the secure world
- * @dev:	device
- * @svc_id:	service identifier
- * @cmd_id:	command identifier
- * @desc:	Descriptor structure containing arguments and return values
- *
- * Sends a command to the SCM and waits for the command to finish processing.
- * This should *only* be called in pre-emptible context.
-*/
-static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
-			 const struct qcom_scm_desc *desc,
-			 struct arm_smccc_res *res)
+static void __qcom_scm_call_do(const struct qcom_scm_desc *desc,
+			       struct arm_smccc_res *res, u32 fn_id,
+			       u64 x5, u32 type)
+{
+	u64 cmd;
+	struct arm_smccc_quirk quirk = {.id = ARM_SMCCC_QUIRK_QCOM_A6};
+
+	cmd = ARM_SMCCC_CALL_VAL(type, qcom_smccc_convention,
+				 ARM_SMCCC_OWNER_SIP, fn_id);
+
+	quirk.state.a6 = 0;
+
+	do {
+		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);
+}
+
+static void qcom_scm_call_do(const struct qcom_scm_desc *desc,
+			     struct arm_smccc_res *res, u32 fn_id,
+			     u64 x5, bool atomic)
+{
+	int retry_count = 0;
+
+	if (!atomic) {
+		do {
+			mutex_lock(&qcom_scm_lock);
+
+			__qcom_scm_call_do(desc, res, fn_id, x5,
+					   ARM_SMCCC_STD_CALL);
+
+			mutex_unlock(&qcom_scm_lock);
+
+			if (res->a0 == QCOM_SCM_V2_EBUSY) {
+				if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY)
+					break;
+				msleep(QCOM_SCM_EBUSY_WAIT_MS);
+			}
+		}  while (res->a0 == QCOM_SCM_V2_EBUSY);
+	} else {
+		__qcom_scm_call_do(desc, res, fn_id, x5, ARM_SMCCC_FAST_CALL);
+	}
+}
+
+static int ___qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
+			    const struct qcom_scm_desc *desc,
+			    struct arm_smccc_res *res, bool atomic)
 {
 	int arglen = desc->arginfo & 0xf;
-	int retry_count = 0, i;
+	int i;
 	u32 fn_id = QCOM_SCM_FNID(svc_id, cmd_id);
-	u64 cmd, x5 = desc->args[FIRST_EXT_ARG_IDX];
+	u64 x5 = desc->args[FIRST_EXT_ARG_IDX];
 	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};
+	gfp_t flag = atomic ? GFP_ATOMIC : GFP_KERNEL;
 
 	if (unlikely(arglen > N_REGISTER_ARGS)) {
 		alloc_len = N_EXT_QCOM_SCM_ARGS * sizeof(u64);
-		args_virt = kzalloc(PAGE_ALIGN(alloc_len), GFP_KERNEL);
+		args_virt = kzalloc(PAGE_ALIGN(alloc_len), flag);
 
 		if (!args_virt)
 			return -ENOMEM;
@@ -117,33 +156,7 @@  static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
 		x5 = args_phys;
 	}
 
-	do {
-		mutex_lock(&qcom_scm_lock);
-
-		cmd = ARM_SMCCC_CALL_VAL(ARM_SMCCC_STD_CALL,
-					 qcom_smccc_convention,
-					 ARM_SMCCC_OWNER_SIP, fn_id);
-
-		quirk.state.a6 = 0;
-
-		do {
-			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);
-
-		if (res->a0 == QCOM_SCM_V2_EBUSY) {
-			if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY)
-				break;
-			msleep(QCOM_SCM_EBUSY_WAIT_MS);
-		}
-	}  while (res->a0 == QCOM_SCM_V2_EBUSY);
+	qcom_scm_call_do(desc, res, fn_id, x5, atomic);
 
 	if (args_virt) {
 		dma_unmap_single(dev, args_phys, alloc_len, DMA_TO_DEVICE);
@@ -156,6 +169,41 @@  static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
 	return 0;
 }
 
+/**
+ * qcom_scm_call() - Invoke a syscall in the secure world
+ * @dev:	device
+ * @svc_id:	service identifier
+ * @cmd_id:	command identifier
+ * @desc:	Descriptor structure containing arguments and return values
+ *
+ * Sends a command to the SCM and waits for the command to finish processing.
+ * This should *only* be called in pre-emptible context.
+ */
+static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
+			 const struct qcom_scm_desc *desc,
+			 struct arm_smccc_res *res)
+{
+	return ___qcom_scm_call(dev, svc_id, cmd_id, desc, res, false);
+}
+
+/**
+ * qcom_scm_call_atomic() - atomic variation of qcom_scm_call()
+ * @dev:	device
+ * @svc_id:	service identifier
+ * @cmd_id:	command identifier
+ * @desc:	Descriptor structure containing arguments and return values
+ * @res:	Structure containing results from SMC/HVC call
+ *
+ * Sends a command to the SCM and waits for the command to finish processing.
+ * This should be called in atomic context only.
+ */
+static int qcom_scm_call_atomic(struct device *dev, u32 svc_id, u32 cmd_id,
+				const struct qcom_scm_desc *desc,
+				struct arm_smccc_res *res)
+{
+	return ___qcom_scm_call(dev, svc_id, cmd_id, desc, res, true);
+}
+
 /**
  * qcom_scm_set_cold_boot_addr() - Set the cold boot address for cpus
  * @entry: Entry point function for the cpus