arm: omap5: secure API for EMIF memory reservations

Create a few public APIs which rely on secure world ROM/HAL
APIs for their implementation. These are intended to be used
to reserve a portion of the EMIF memory and configure hardware
firewalls around that region to prevent public code from
manipulating or interfering with that memory.

Signed-off-by: Daniel Allred <d-allred@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/arm/cpu/armv7/omap5/Makefile

@@ -14,3 +14,4 @@ obj-y	+= hw_data.o
 obj-y	+= abb.o
 obj-y	+= fdt.o
 obj-$(CONFIG_IODELAY_RECALIBRATION) += dra7xx_iodelay.o
+obj-$(CONFIG_TI_SECURE_DEVICE) += sec-fxns.o

arch/arm/cpu/armv7/omap5/sec-fxns.c

@@ -0,0 +1,126 @@
+/*
+ *
+ * Security related functions for OMAP5 class devices
+ *
+ * (C) Copyright 2016
+ * Texas Instruments, <www.ti.com>
+ *
+ * Daniel Allred <d-allred@ti.com>
+ * Harinarayan Bhatta <harinarayan@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>
+#include <asm/spl.h>
+#include <spl.h>
+
+/* Index for signature PPA-based TI HAL APIs */
+#define PPA_HAL_SERVICES_START_INDEX        (0x200)
+#define PPA_SERV_HAL_SETUP_SEC_RESVD_REGION (PPA_HAL_SERVICES_START_INDEX + 25)
+#define PPA_SERV_HAL_SETUP_EMIF_FW_REGION   (PPA_HAL_SERVICES_START_INDEX + 26)
+#define PPA_SERV_HAL_LOCK_EMIF_FW           (PPA_HAL_SERVICES_START_INDEX + 27)
+
+static u32 get_sec_mem_start(void)
+{
+	u32 sec_mem_start = CONFIG_TI_SECURE_EMIF_REGION_START;
+	u32 sec_mem_size = CONFIG_TI_SECURE_EMIF_TOTAL_REGION_SIZE;
+	/*
+	 * Total reserved region is all contiguous with protected
+	 * region coming first, followed by the non-secure region.
+	 * If 0x0 start address is given, we simply put the reserved
+	 * region at the end of the external DRAM.
+	 */
+	if (sec_mem_start == 0)
+		sec_mem_start =
+			(CONFIG_SYS_SDRAM_BASE +
+			(omap_sdram_size() - sec_mem_size));
+	return sec_mem_start;
+}
+
+int secure_emif_firewall_setup(uint8_t region_num, uint32_t start_addr,
+			       uint32_t size, uint32_t access_perm,
+			       uint32_t initiator_perm)
+{
+	int result = 1;
+
+	/*
+	 * Call PPA HAL API to do any other general firewall
+	 * configuration for regions 1-6 of the EMIF firewall.
+	 */
+	debug("%s: regionNum = %x, startAddr = %x, size = %x", __func__,
+	      region_num, start_addr, size);
+
+	result = secure_rom_call(
+			PPA_SERV_HAL_SETUP_EMIF_FW_REGION, 0, 0, 4,
+			(start_addr & 0xFFFFFFF0) | (region_num & 0x0F),
+			size, access_perm, initiator_perm);
+
+	if (result != 0) {
+		puts("Secure EMIF Firewall Setup failed!\n");
+		debug("Return Value = %x\n", result);
+	}
+
+	return result;
+}
+
+#if	(CONFIG_TI_SECURE_EMIF_TOTAL_REGION_SIZE <  \
+	CONFIG_TI_SECURE_EMIF_PROTECTED_REGION_SIZE)
+#error	"TI Secure EMIF: Protected size cannot be larger than total size."
+#endif
+int secure_emif_reserve(void)
+{
+	int result = 1;
+	u32 sec_mem_start = get_sec_mem_start();
+	u32 sec_prot_size = CONFIG_TI_SECURE_EMIF_PROTECTED_REGION_SIZE;
+
+	/* If there is no protected region, there is no reservation to make */
+	if (sec_prot_size == 0)
+		return 0;
+
+	/*
+	 * Call PPA HAL API to reserve a chunk of EMIF SDRAM
+	 * for secure world use. This region should be carved out
+	 * from use by any public code. EMIF firewall region 7
+	 * will be used to protect this block of memory.
+	 */
+	result = secure_rom_call(
+			PPA_SERV_HAL_SETUP_SEC_RESVD_REGION,
+			0, 0, 2, sec_mem_start, sec_prot_size);
+
+	if (result != 0) {
+		puts("SDRAM Firewall: Secure memory reservation failed!\n");
+		debug("Return Value = %x\n", result);
+	}
+
+	return result;
+}
+
+int secure_emif_firewall_lock(void)
+{
+	int result = 1;
+
+	/*
+	 * Call PPA HAL API to lock the EMIF firewall configurations.
+	 * After this API is called, none of the PPA HAL APIs for
+	 * configuring the EMIF firewalls will be usable again (that
+	 * is, calls to those APIs will return failure and have no
+	 * effect).
+	 */
+
+	result = secure_rom_call(
+			PPA_SERV_HAL_LOCK_EMIF_FW,
+			0, 0, 0);
+
+	if (result != 0) {
+		puts("Secure EMIF Firewall Lock failed!\n");
+		debug("Return Value = %x\n", result);
+	}
+
+	return result;
+}

arch/arm/include/asm/omap_sec_common.h

@@ -27,4 +27,28 @@ u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...);
  */
 int secure_boot_verify_image(void **p_image, size_t *p_size);
 
+/*
+ * Invoke a secure HAL API that allows configuration of the external memory
+ * firewall regions.
+ */
+int secure_emif_firewall_setup(uint8_t region_num, uint32_t start_addr,
+			       uint32_t size, uint32_t access_perm,
+			       uint32_t initiator_perm);
+
+/*
+ * Invoke a secure HAL API on high-secure (HS) device variants that reserves a
+ * region of external memory for secure world use, and protects it using memory
+ * firewalls that prevent public world access. This API is intended to setaside
+ * memory that will be used for a secure world OS/TEE.
+ */
+int secure_emif_reserve(void);
+
+/*
+ * Invoke a secure HAL API to lock the external memory firewall configurations.
+ * After this API is called, none of the HAL APIs for configuring the that
+ * firewall will be usable (calls to those APIs will return failure and have
+ * no effect).
+ */
+int secure_emif_firewall_lock(void);
+
 #endif /* _OMAP_SEC_COMMON_H_ */