Commit 1a5ea3b7 authored by Vivek Gautam's avatar Vivek Gautam Committed by Will Deacon
Browse files

firmware: qcom_scm-64: Add atomic version of qcom_scm_call 

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: default avatarVivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: default avatarStephen Boyd <swboyd@chromium.org>
Acked-by: default avatarAndy Gross <agross@kernel.org>
Signed-off-by: default avatarSai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent ff34f3cc

drivers/firmware/qcom_scm-64.c

+94 −44
Original line number Diff line number Diff line
@@ -62,32 +62,72 @@ 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,

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) {

		__qcom_scm_call_do(desc, res, fn_id, x5, ARM_SMCCC_FAST_CALL);

		return;

	}



	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);

}



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)

			    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 +157,7 @@ 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 +170,42 @@ 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)

{

	might_sleep();

	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 can be called in atomic context.

 */

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

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