firmware: qcom: scm: Use atomic SCM for cold boot

This patch changes the cold_set_boot_addr function to use atomic SCM
calls.  cold_set_boot_addr required adding qcom_scm_call_atomic2 to
support the two arguments going to the smc call.  Using atomic removes
the need for memory allocation and instead places all arguments in
registers.

Signed-off-by: Andy Gross <andy.gross@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>

1 files changed, 45 insertions, 18 deletions

diff --git a/drivers/firmware/qcom_scm-32.c b/drivers/firmware/qcom_scm-32.c
index 0883292f640f..5be6a123ac70 100644
--- a/drivers/firmware/qcom_scm-32.c
+++ b/drivers/firmware/qcom_scm-32.c
@@ -342,6 +342,41 @@ static s32 qcom_scm_call_atomic1(u32 svc, u32 cmd, u32 arg1)
         return r0;
 }
 
+/**
+ * qcom_scm_call_atomic2() - Send an atomic SCM command with two arguments
+ * @svc_id:     service identifier
+ * @cmd_id:     command identifier
+ * @arg1:       first argument
+ * @arg2:       second argument
+ *
+ * This shall only be used with commands that are guaranteed to be
+ * uninterruptable, atomic and SMP safe.
+ */
+static s32 qcom_scm_call_atomic2(u32 svc, u32 cmd, u32 arg1, u32 arg2)
+{
+        int context_id;
+
+        register u32 r0 asm("r0") = SCM_ATOMIC(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)
+                        );
+        return r0;
+}
+
 u32 qcom_scm_get_version(void)
 {
         int context_id;
@@ -378,22 +413,6 @@ u32 qcom_scm_get_version(void)
 }
 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)
-{
-        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);
-}
-
 /**
  * qcom_scm_set_cold_boot_addr() - Set the cold boot address for cpus
  * @entry: Entry point function for the cpus
@@ -423,7 +442,8 @@ 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_call_atomic2(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
+                                    flags, virt_to_phys(entry));
 }
 
 /**
@@ -439,6 +459,10 @@ int __qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
         int ret;
         int flags = 0;
         int cpu;
+        struct {
+                __le32 flags;
+                __le32 addr;
+        } cmd;
 
         /*
          * Reassign only if we are switching from hotplug entry point
@@ -454,7 +478,10 @@ 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);
+        cmd.addr = cpu_to_le32(virt_to_phys(entry));
+        cmd.flags = cpu_to_le32(flags);
+        ret = qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
+                            &cmd, sizeof(cmd), NULL, 0);
         if (!ret) {
                 for_each_cpu(cpu, cpus)
                         qcom_scm_wb[cpu].entry = entry;