firmware: qcom_scm-32: replace open-coded call to __cpuc_flush_dcache_area()

Rathe rthan directly accessing architecture internal functions, provide
an "method"-centric wrapper for qcom_scm-32 to do what's necessary to
ensure that the secure monitor can see the data.  This is called
"secure_flush_area" and ensures that the specified memory area is
coherent across the secure boundary.

Acked-by: Andy Gross <agross@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 18 insertions, 3 deletions

diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
index c5230a44eeca..d5525bfc7e3e 100644
--- a/arch/arm/include/asm/cacheflush.h
+++ b/arch/arm/include/asm/cacheflush.h
@@ -502,4 +502,21 @@ static inline void set_kernel_text_ro(void) { }
 void flush_uprobe_xol_access(struct page *page, unsigned long uaddr,
                              void *kaddr, unsigned long len);
 
+/**
+ * secure_flush_area - ensure coherency across the secure boundary
+ * @addr: virtual address
+ * @size: size of region
+ *
+ * Ensure that the specified area of memory is coherent across the secure
+ * boundary from the non-secure side.  This is used when calling secure
+ * firmware where the secure firmware does not ensure coherency.
+ */
+static inline void secure_flush_area(const void *addr, size_t size)
+{
+        phys_addr_t phys = __pa(addr);
+
+        __cpuc_flush_dcache_area((void *)addr, size);
+        outer_flush_range(phys, phys + size);
+}
+
 #endif
diff --git a/drivers/firmware/qcom_scm-32.c b/drivers/firmware/qcom_scm-32.c
index 1bd6f9c34331..29e6850665eb 100644
--- a/drivers/firmware/qcom_scm-32.c
+++ b/drivers/firmware/qcom_scm-32.c
@@ -24,7 +24,6 @@
 #include <linux/err.h>
 #include <linux/qcom_scm.h>
 
-#include <asm/outercache.h>
 #include <asm/cacheflush.h>
 
 #include "qcom_scm.h"
@@ -219,8 +218,7 @@ static int __qcom_scm_call(const struct qcom_scm_command *cmd)
          * Flush the command buffer so that the secure world sees
          * the correct data.
          */
-        __cpuc_flush_dcache_area((void *)cmd, cmd->len);
-        outer_flush_range(cmd_addr, cmd_addr + cmd->len);
+        secure_flush_area(cmd, cmd->len);
 
         ret = smc(cmd_addr);
         if (ret < 0)