firmware: qcom: scm: Add support for ARM64 SoCs

Add an implementation of the SCM interface that works on ARM64 SoCs.  This
is used by things like determine if we have HDCP support or not on the
system.
Signed-off-by: Kumar Gala <galak@codeaurora.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/firmware/qcom_scm-32.c

@@ -454,3 +454,7 @@ int __qcom_scm_hdcp_req(struct device *dev, struct qcom_scm_hdcp_req *req,
 	return qcom_scm_call(dev, QCOM_SCM_SVC_HDCP, QCOM_SCM_CMD_HDCP,
 		req, req_cnt * sizeof(*req), resp, sizeof(*resp));
 }
+
+void __qcom_scm_init(void)
+{
+}

drivers/firmware/qcom_scm-64.c

@@ -12,7 +12,143 @@
 
 #include <linux/io.h>
 #include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/types.h>
 #include <linux/qcom_scm.h>
+#include <linux/arm-smccc.h>
+#include <linux/dma-mapping.h>
+
+#include "qcom_scm.h"
+
+#define QCOM_SCM_FNID(s, c) ((((s) & 0xFF) << 8) | ((c) & 0xFF))
+
+#define MAX_QCOM_SCM_ARGS 10
+#define MAX_QCOM_SCM_RETS 3
+
+#define QCOM_SCM_ARGS_IMPL(num, a, b, c, d, e, f, g, h, i, j, ...) (\
+			   (((a) & 0x3) << 4) | \
+			   (((b) & 0x3) << 6) | \
+			   (((c) & 0x3) << 8) | \
+			   (((d) & 0x3) << 10) | \
+			   (((e) & 0x3) << 12) | \
+			   (((f) & 0x3) << 14) | \
+			   (((g) & 0x3) << 16) | \
+			   (((h) & 0x3) << 18) | \
+			   (((i) & 0x3) << 20) | \
+			   (((j) & 0x3) << 22) | \
+			   ((num) & 0xf))
+
+#define QCOM_SCM_ARGS(...) QCOM_SCM_ARGS_IMPL(__VA_ARGS__, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
+
+/**
+ * struct qcom_scm_desc
+ * @arginfo:	Metadata describing the arguments in args[]
+ * @args:	The array of arguments for the secure syscall
+ * @res:	The values returned by the secure syscall
+ */
+struct qcom_scm_desc {
+	u32 arginfo;
+	u64 args[MAX_QCOM_SCM_ARGS];
+};
+
+static u64 qcom_smccc_convention = -1;
+static DEFINE_MUTEX(qcom_scm_lock);
+
+#define QCOM_SCM_EBUSY_WAIT_MS 30
+#define QCOM_SCM_EBUSY_MAX_RETRY 20
+
+#define N_EXT_QCOM_SCM_ARGS 7
+#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)
+{
+	int arglen = desc->arginfo & 0xf;
+	int retry_count = 0, i;
+	u32 fn_id = QCOM_SCM_FNID(svc_id, cmd_id);
+	u64 cmd, x5 = desc->args[FIRST_EXT_ARG_IDX];
+	dma_addr_t args_phys = 0;
+	void *args_virt = NULL;
+	size_t alloc_len;
+
+	if (unlikely(arglen > N_REGISTER_ARGS)) {
+		alloc_len = N_EXT_QCOM_SCM_ARGS * sizeof(u64);
+		args_virt = kzalloc(PAGE_ALIGN(alloc_len), GFP_KERNEL);
+
+		if (!args_virt)
+			return -ENOMEM;
+
+		if (qcom_smccc_convention == ARM_SMCCC_SMC_32) {
+			__le32 *args = args_virt;
+
+			for (i = 0; i < N_EXT_QCOM_SCM_ARGS; i++)
+				args[i] = cpu_to_le32(desc->args[i +
+						      FIRST_EXT_ARG_IDX]);
+		} else {
+			__le64 *args = args_virt;
+
+			for (i = 0; i < N_EXT_QCOM_SCM_ARGS; i++)
+				args[i] = cpu_to_le64(desc->args[i +
+						      FIRST_EXT_ARG_IDX]);
+		}
+
+		args_phys = dma_map_single(dev, args_virt, alloc_len,
+					   DMA_TO_DEVICE);
+
+		if (dma_mapping_error(dev, args_phys)) {
+			kfree(args_virt);
+			return -ENOMEM;
+		}
+
+		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);
+
+		do {
+			arm_smccc_smc(cmd, desc->arginfo, desc->args[0],
+				      desc->args[1], desc->args[2], x5, 0, 0,
+				      res);
+		} 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);
+
+	if (args_virt) {
+		dma_unmap_single(dev, args_phys, alloc_len, DMA_TO_DEVICE);
+		kfree(args_virt);
+	}
+
+	if (res->a0 < 0)
+		return qcom_scm_remap_error(res->a0);
+
+	return 0;
+}
 
 /**
  * qcom_scm_set_cold_boot_addr() - Set the cold boot address for cpus
@@ -29,13 +165,15 @@ int __qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus)
 
 /**
  * qcom_scm_set_warm_boot_addr() - Set the warm boot address for cpus
+ * @dev: Device pointer
  * @entry: Entry point function for the cpus
  * @cpus: The cpumask of cpus that will use the entry point
  *
  * Set the Linux entry point for the SCM to transfer control to when coming
  * out of a power down. CPU power down may be executed on cpuidle or hotplug.
  */
-int __qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
+int __qcom_scm_set_warm_boot_addr(struct device *dev, void *entry,
+				  const cpumask_t *cpus)
 {
 	return -ENOTSUPP;
 }
@@ -52,12 +190,66 @@ void __qcom_scm_cpu_power_down(u32 flags)
 {
 }
 
-int __qcom_scm_is_call_available(u32 svc_id, u32 cmd_id)
+int __qcom_scm_is_call_available(struct device *dev, u32 svc_id, u32 cmd_id)
 {
-	return -ENOTSUPP;
+	int ret;
+	struct qcom_scm_desc desc = {0};
+	struct arm_smccc_res res;
+
+	desc.arginfo = QCOM_SCM_ARGS(1);
+	desc.args[0] = QCOM_SCM_FNID(svc_id, cmd_id) |
+			(ARM_SMCCC_OWNER_SIP << ARM_SMCCC_OWNER_SHIFT);
+
+	ret = qcom_scm_call(dev, QCOM_SCM_SVC_INFO, QCOM_IS_CALL_AVAIL_CMD,
+			    &desc, &res);
+
+	return ret ? : res.a1;
 }
 
-int __qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp)
+int __qcom_scm_hdcp_req(struct device *dev, struct qcom_scm_hdcp_req *req,
+			u32 req_cnt, u32 *resp)
 {
-	return -ENOTSUPP;
+	int ret;
+	struct qcom_scm_desc desc = {0};
+	struct arm_smccc_res res;
+
+	if (req_cnt > QCOM_SCM_HDCP_MAX_REQ_CNT)
+		return -ERANGE;
+
+	desc.args[0] = req[0].addr;
+	desc.args[1] = req[0].val;
+	desc.args[2] = req[1].addr;
+	desc.args[3] = req[1].val;
+	desc.args[4] = req[2].addr;
+	desc.args[5] = req[2].val;
+	desc.args[6] = req[3].addr;
+	desc.args[7] = req[3].val;
+	desc.args[8] = req[4].addr;
+	desc.args[9] = req[4].val;
+	desc.arginfo = QCOM_SCM_ARGS(10);
+
+	ret = qcom_scm_call(dev, QCOM_SCM_SVC_HDCP, QCOM_SCM_CMD_HDCP, &desc,
+			    &res);
+	*resp = res.a1;
+
+	return ret;
+}
+
+void __qcom_scm_init(void)
+{
+	u64 cmd;
+	struct arm_smccc_res res;
+	u32 function = QCOM_SCM_FNID(QCOM_SCM_SVC_INFO, QCOM_IS_CALL_AVAIL_CMD);
+
+	/* 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;
 }

drivers/firmware/qcom_scm.c

@@ -190,6 +190,8 @@ static int qcom_scm_probe(struct platform_device *pdev)
 	__scm = scm;
 	__scm->dev = &pdev->dev;
 
+	__qcom_scm_init();
+
 	return 0;
 }
 

drivers/firmware/qcom_scm.h

@@ -38,7 +38,10 @@ extern int __qcom_scm_is_call_available(struct device *dev, u32 svc_id,
 extern int __qcom_scm_hdcp_req(struct device *dev,
 		struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp);
 
+extern void __qcom_scm_init(void);
+
 /* common error codes */
+#define QCOM_SCM_V2_EBUSY	-12
 #define QCOM_SCM_ENOMEM		-5
 #define QCOM_SCM_EOPNOTSUPP	-4
 #define QCOM_SCM_EINVAL_ADDR	-3
@@ -58,6 +61,8 @@ static inline int qcom_scm_remap_error(int err)
 		return -EOPNOTSUPP;
 	case QCOM_SCM_ENOMEM:
 		return -ENOMEM;
+	case QCOM_SCM_V2_EBUSY:
+		return -EBUSY;
 	}
 	return -EINVAL;
 }