linux-kernel - [PATCH 5/8] firmware: qcom: scm: Use atomic SCM for cold boot

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Message-Id: <1461363432-5730-6-git-send-email-andy.gross@linaro.org>
Date:	Fri, 22 Apr 2016 17:17:09 -0500
From:	Andy Gross <andy.gross@...aro.org>
To:	linux-arm-msm@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Stephen Boyd <sboyd@...eaurora.org>,
	devicetree@...r.kernel.org,
	Bjorn Andersson <bjorn.andersson@...ymobile.com>,
	jilai wang <jilaiw@...eaurora.org>,
	Andy Gross <andy.gross@...aro.org>
Subject: [PATCH 5/8] firmware: qcom: scm: Use atomic SCM for cold boot

This patch changes the cold_set_boot_addr function to use atomic SCM
calls.  This removes the need for memory allocation and instead places
all arguments in registers.

Signed-off-by: Andy Gross <andy.gross@...aro.org>
---
 drivers/firmware/qcom_scm-32.c | 40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/drivers/firmware/qcom_scm-32.c b/drivers/firmware/qcom_scm-32.c
index 0d2a3f8..f596091 100644
--- a/drivers/firmware/qcom_scm-32.c
+++ b/drivers/firmware/qcom_scm-32.c
@@ -294,34 +294,39 @@ out:
 				(n & 0xf))
 
 /**
- * qcom_scm_call_atomic1() - Send an atomic SCM command with one argument
+ * qcom_scm_call_atomic() - Send an atomic SCM command with one argument
  * @svc_id: service identifier
  * @cmd_id: command identifier
+ * @arglen: number of arguments
  * @arg1: first argument
+ * @arg2: second argument (optional - fill with 0 if unused)
  *
  * This shall only be used with commands that are guaranteed to be
  * uninterruptable, atomic and SMP safe.
  */
-static s32 qcom_scm_call_atomic1(u32 svc, u32 cmd, u32 arg1)
+static s32 qcom_scm_call_atomic(u32 svc, u32 cmd, u32 arglen, u32 arg1,
+				u32 arg2)
 {
 	int context_id;
 
-	register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 1);
+	register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, arglen);
 	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)
-			: "r3");
+			: "r" (r0), "r" (r1), "r" (r2), "r" (r3)
+			);
 	return r0;
 }
 
@@ -364,17 +369,24 @@ EXPORT_SYMBOL(qcom_scm_get_version);
 /*
  * Set the cold/warm boot address for one of the CPU cores.
  */
-static int qcom_scm_set_boot_addr(u32 addr, int flags)
+static int qcom_scm_set_boot_addr(u32 addr, int flags, bool do_atomic)
 {
 	struct {
 		__le32 flags;
 		__le32 addr;
 	} cmd;
 
-	cmd.addr = cpu_to_le32(addr);
-	cmd.flags = cpu_to_le32(flags);
-	return qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
-			&cmd, sizeof(cmd), NULL, 0);
+	if (do_atomic) {
+		return qcom_scm_call_atomic(QCOM_SCM_SVC_BOOT,
+					    QCOM_SCM_BOOT_ADDR, 2, flags, addr);
+	} else {
+
+		cmd.addr = cpu_to_le32(addr);
+		cmd.flags = cpu_to_le32(flags);
+
+		return qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
+				     &cmd, sizeof(cmd), NULL, 0);
+	}
 }
 
 /**
@@ -406,7 +418,7 @@ int __qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus)
 			set_cpu_present(cpu, false);
 	}
 
-	return qcom_scm_set_boot_addr(virt_to_phys(entry), flags);
+	return qcom_scm_set_boot_addr(virt_to_phys(entry), flags, true);
 }
 
 /**
@@ -437,7 +449,7 @@ int __qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
 	if (!flags)
 		return 0;
 
-	ret = qcom_scm_set_boot_addr(virt_to_phys(entry), flags);
+	ret = qcom_scm_set_boot_addr(virt_to_phys(entry), flags, false);
 	if (!ret) {
 		for_each_cpu(cpu, cpus)
 			qcom_scm_wb[cpu].entry = entry;
@@ -456,8 +468,8 @@ int __qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
  */
 void __qcom_scm_cpu_power_down(u32 flags)
 {
-	qcom_scm_call_atomic1(QCOM_SCM_SVC_BOOT, QCOM_SCM_CMD_TERMINATE_PC,
-			flags & QCOM_SCM_FLUSH_FLAG_MASK);
+	qcom_scm_call_atomic(QCOM_SCM_SVC_BOOT, QCOM_SCM_CMD_TERMINATE_PC, 1,
+			flags & QCOM_SCM_FLUSH_FLAG_MASK, 0);
 }
 
 int __qcom_scm_is_call_available(u32 svc_id, u32 cmd_id)
-- 
1.9.1