arm: omap-common: add secure rom call API for secure devices

Adds a generic C-callable API for making secure ROM calls on OMAP and
OMAP-compatible devices. This API provides the important function of
flushing the ROM call arguments to memory from the cache, so that the
secure world will have a coherent view of those arguments. Then is
simply calls the omap_smc_sec routine.

Signed-off-by: Daniel Allred <d-allred@ti.com>
Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/arm/cpu/armv7/omap-common/Makefile

@@ -36,3 +36,5 @@ obj-y	+= boot-common.o
 obj-y	+= lowlevel_init.o
 
 obj-y	+= mem-common.o
+
+obj-$(CONFIG_TI_SECURE_DEVICE) += sec-common.o

arch/arm/cpu/armv7/omap-common/sec-common.c

+/*
+ *
+ * Common security related functions for OMAP devices
+ *
+ * (C) Copyright 2016
+ * Texas Instruments, <www.ti.com>
+ *
+ * Daniel Allred <d-allred@ti.com>
+ * Andreas Dannenberg <dannenberg@ti.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <stdarg.h>
+
+#include <asm/arch/sys_proto.h>
+#include <asm/omap_common.h>
+#include <asm/omap_sec_common.h>
+
+static uint32_t secure_rom_call_args[5] __aligned(ARCH_DMA_MINALIGN);
+
+u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...)
+{
+	int i;
+	u32 num_args;
+	va_list ap;
+
+	va_start(ap, flag);
+
+	num_args = va_arg(ap, u32);
+
+	if (num_args > 4)
+		return 1;
+
+	/* Copy args to aligned args structure */
+	for (i = 0; i < num_args; i++)
+		secure_rom_call_args[i + 1] = va_arg(ap, u32);
+
+	secure_rom_call_args[0] = num_args;
+
+	va_end(ap);
+
+	/* if data cache is enabled, flush the aligned args structure */
+	flush_dcache_range(
+		(unsigned int)&secure_rom_call_args[0],
+		(unsigned int)&secure_rom_call_args[0] +
+		roundup(sizeof(secure_rom_call_args), ARCH_DMA_MINALIGN));
+
+	return omap_smc_sec(service, proc_id, flag, secure_rom_call_args);
+}

arch/arm/include/asm/omap_sec_common.h

+/*
+ * (C) Copyright 2016
+ * Texas Instruments, <www.ti.com>
+ *
+ * Andreas Dannenberg <dannenberg@ti.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+#ifndef	_OMAP_SEC_COMMON_H_
+#define	_OMAP_SEC_COMMON_H_
+
+#include <common.h>
+
+/*
+ * Invoke secure ROM API on high-security (HS) device variants. It formats
+ * the variable argument list into the format expected by the ROM code before
+ * triggering the actual low-level smc entry.
+ */
+u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...);
+
+#endif /* _OMAP_SEC_COMMON_H_ */