firmware: qcom_scm-32: Use SMC arch wrappers

Use SMC arch wrappers instead of inline assembly.

Tested-by: Brian Masney <masneyb@onstation.org> # arm32
Tested-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Elliot Berman <eberman@codeaurora.org>
Link: https://lore.kernel.org/r/1578431066-19600-10-git-send-email-eberman@codeaurora.orgSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/firmware/Makefile

@@ -20,7 +20,6 @@ obj-$(CONFIG_FW_CFG_SYSFS)	+= qemu_fw_cfg.o
 obj-$(CONFIG_QCOM_SCM)		+= qcom_scm.o
 obj-$(CONFIG_QCOM_SCM_64)	+= qcom_scm-64.o
 obj-$(CONFIG_QCOM_SCM_32)	+= qcom_scm-32.o
-CFLAGS_qcom_scm-32.o :=$(call as-instr,.arch armv7-a\n.arch_extension sec,-DREQUIRES_SEC=1) -march=armv7-a
 obj-$(CONFIG_TI_SCI_PROTOCOL)	+= ti_sci.o
 obj-$(CONFIG_TRUSTED_FOUNDATIONS) += trusted_foundations.o
 obj-$(CONFIG_TURRIS_MOX_RWTM)	+= turris-mox-rwtm.o

drivers/firmware/qcom_scm-32.c

@@ -10,6 +10,7 @@
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/qcom_scm.h>
+#include <linux/arm-smccc.h>
 #include <linux/dma-mapping.h>
 
 #include "qcom_scm.h"
@@ -121,25 +122,13 @@ static inline void *scm_legacy_get_response_buffer(
 static u32 __scm_legacy_do(u32 cmd_addr)
 {
 	int context_id;
-	register u32 r0 asm("r0") = 1;
-	register u32 r1 asm("r1") = (u32)&context_id;
-	register u32 r2 asm("r2") = cmd_addr;
+	struct arm_smccc_res res;
 	do {
-		asm volatile(
-			__asmeq("%0", "r0")
-			__asmeq("%1", "r0")
-			__asmeq("%2", "r1")
-			__asmeq("%3", "r2")
-#ifdef REQUIRES_SEC
-			".arch_extension sec\n"
-#endif
-			"smc	#0	@ switch to secure world\n"
-			: "=r" (r0)
-			: "r" (r0), "r" (r1), "r" (r2)
-			: "r3", "r12");
-	} while (r0 == QCOM_SCM_INTERRUPTED);
-
-	return r0;
+		arm_smccc_smc(1, (unsigned long)&context_id, cmd_addr,
+			      0, 0, 0, 0, 0, &res);
+	} while (res.a0 == QCOM_SCM_INTERRUPTED);
+
+	return res.a0;
 }
 
 /**
@@ -237,24 +226,12 @@ static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
 static s32 qcom_scm_call_atomic1(u32 svc, u32 cmd, u32 arg1)
 {
 	int context_id;
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(SCM_LEGACY_ATOMIC_ID(svc, cmd, 1),
+		      (unsigned long)&context_id, arg1, 0, 0, 0, 0, 0, &res);
 
-	register u32 r0 asm("r0") = SCM_LEGACY_ATOMIC_ID(svc, cmd, 1);
-	register u32 r1 asm("r1") = (u32)&context_id;
-	register u32 r2 asm("r2") = arg1;
-
-	asm volatile(
-			__asmeq("%0", "r0")
-			__asmeq("%1", "r0")
-			__asmeq("%2", "r1")
-			__asmeq("%3", "r2")
-#ifdef REQUIRES_SEC
-			".arch_extension sec\n"
-#endif
-			"smc    #0      @ switch to secure world\n"
-			: "=r" (r0)
-			: "r" (r0), "r" (r1), "r" (r2)
-			: "r3", "r12");
-	return r0;
+	return res.a0;
 }
 
 /**
@@ -270,26 +247,12 @@ static s32 qcom_scm_call_atomic1(u32 svc, u32 cmd, u32 arg1)
 static s32 qcom_scm_call_atomic2(u32 svc, u32 cmd, u32 arg1, u32 arg2)
 {
 	int context_id;
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(SCM_LEGACY_ATOMIC_ID(svc, cmd, 2),
+		      (unsigned long)&context_id, arg1, 0, 0, 0, 0, 0, &res);
 
-	register u32 r0 asm("r0") = SCM_LEGACY_ATOMIC_ID(svc, cmd, 2);
-	register u32 r1 asm("r1") = (u32)&context_id;
-	register u32 r2 asm("r2") = arg1;
-	register u32 r3 asm("r3") = arg2;
-
-	asm volatile(
-			__asmeq("%0", "r0")
-			__asmeq("%1", "r0")
-			__asmeq("%2", "r1")
-			__asmeq("%3", "r2")
-			__asmeq("%4", "r3")
-#ifdef REQUIRES_SEC
-			".arch_extension sec\n"
-#endif
-			"smc    #0      @ switch to secure world\n"
-			: "=r" (r0)
-			: "r" (r0), "r" (r1), "r" (r2), "r" (r3)
-			: "r12");
-	return r0;
+	return res.a0;
 }
 
 /**