arm: omap5: Add function to make an SMC call on cpu1

On DRA7xx platform, CPU Core 1 is not used in u-boot. However, in some
cases it is need to make secure API calls from Core 1. This patch adds
an assembly function to make a secure (SMC) call from CPU Core #1.

Signed-off-by: Harinarayan Bhatta <harinarayan@ti.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

2 files changed, 124 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/omap5/Makefile b/arch/arm/mach-omap2/omap5/Makefile
index 0212df7..af17a3d 100644
--- a/arch/arm/mach-omap2/omap5/Makefile
+++ b/arch/arm/mach-omap2/omap5/Makefile
@@ -15,3 +15,4 @@ obj-y	+= abb.o
 obj-y	+= fdt.o
 obj-$(CONFIG_IODELAY_RECALIBRATION) += dra7xx_iodelay.o
 obj-$(CONFIG_TI_SECURE_DEVICE) += sec-fxns.o
+obj-$(CONFIG_DRA7XX) += sec_entry_cpu1.o
diff --git a/arch/arm/mach-omap2/omap5/sec_entry_cpu1.S b/arch/arm/mach-omap2/omap5/sec_entry_cpu1.S
new file mode 100644
index 0000000..c2a35ee
--- /dev/null
+++ b/arch/arm/mach-omap2/omap5/sec_entry_cpu1.S
@@ -0,0 +1,123 @@
+/*
+ * Secure entry function for CPU Core #1
+ *
+ * (C) Copyright 2016
+ * Texas Instruments, <www.ti.com>
+ *
+ * Author :
+ *	Harinarayan Bhatta <harinarayan@ti.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <asm/arch/omap.h>
+#include <asm/omap_common.h>
+#include <linux/linkage.h>
+
+.arch_extension sec
+
+#if !defined(CONFIG_SYS_DCACHE_OFF)
+.global flush_dcache_range
+#endif
+
+#define AUX_CORE_BOOT_0		0x48281800
+#define AUX_CORE_BOOT_1		0x48281804
+
+#ifdef CONFIG_DRA7XX
+/* DRA7xx ROM code function "startup_BootSlave". This function is where CPU1
+ * waits on WFE, polling on AUX_CORE_BOOT_x registers.
+ * This address is same for J6 and J6 Eco.
+ */
+#define ROM_FXN_STARTUP_BOOTSLAVE     0x00038a64
+#endif
+
+/* Assembly core where CPU1 is woken up into
+ * No need to save-restore registers, does not use stack.
+ */
+LENTRY(cpu1_entry)
+	ldr	r4, =omap_smc_sec_cpu1_args
+	ldm	r4, {r0,r1,r2,r3}	@ Retrieve args
+
+	mov	r6, #0xFF	@ Indicate new Task call
+	mov	r12, #0x00	@ Secure Service ID in R12
+
+	dsb
+	dmb
+	smc	0		@ SMC #0 to enter monitor mode
+
+	b	.Lend		@ exit at end of the service execution
+	nop
+
+	@ In case of IRQ happening in Secure, then ARM will branch here.
+	@ At that moment, IRQ will be pending and ARM will jump to Non Secure
+	@ IRQ handler
+	mov	r12, #0xFE
+
+	dsb
+	dmb
+	smc	0		@ SMC #0 to enter monitor mode
+
+.Lend:
+	ldr	r4, =omap_smc_sec_cpu1_args
+	str	r0, [r4, #0x10]		@ save return value
+	ldr	r4, =AUX_CORE_BOOT_0
+	mov	r5, #0x0
+	str	r5, [r4]
+	ldr	r4, =ROM_FXN_STARTUP_BOOTSLAVE
+	sev				@ Tell CPU0 we are done
+	bx	r4			@ Jump back to ROM
+END(cpu1_entry)
+
+/*
+ * u32 omap_smc_sec_cpu1(u32 service, u32 proc_id, u32 flag, u32 *params);
+ *
+ * Makes a secure ROM/PPA call on CPU Core #1 on supported platforms.
+ * Assumes that CPU #1 is waiting in ROM code and not yet woken up or used by
+ * u-boot.
+ */
+ENTRY(omap_smc_sec_cpu1)
+	push	{r4, r5, lr}
+	ldr	r4, =omap_smc_sec_cpu1_args
+	stm	r4, {r0,r1,r2,r3}	@ Save args to memory
+#if !defined(CONFIG_SYS_DCACHE_OFF)
+	mov	r0, r4
+	mov	r1, #CONFIG_SYS_CACHELINE_SIZE
+	add	r1, r0, r1		@ dcache is not enabled on CPU1, so
+	blx	flush_dcache_range	@ flush the cache on args buffer
+#endif
+	ldr	r4, =AUX_CORE_BOOT_1
+	ldr	r5, =cpu1_entry
+	str	r5, [r4]		@ Setup CPU1 entry function
+	ldr	r4, =AUX_CORE_BOOT_0
+	mov	r5, #0x10
+	str	r5, [r4]		@ Tell ROM to exit while loop
+	sev				@ Wake up CPU1
+.Lwait:
+	wfe				@ Wait for CPU1 to finish
+	nop
+	ldr	r5, [r4]		@ Check if CPU1 is done
+	cmp	r5, #0
+	bne	.Lwait
+
+	ldr	r4, =omap_smc_sec_cpu1_args
+	ldr	r0, [r4, #0x10]         @ Retrieve return value
+	pop	{r4, r5, pc}
+ENDPROC(omap_smc_sec_cpu1)
+
+/*
+ * Buffer to save function arguments and return value for omap_smc_sec_cpu1
+ */
+.section .data
+omap_smc_sec_cpu1_args:
+#if !defined(CONFIG_SYS_DCACHE_OFF)
+	.balign CONFIG_SYS_CACHELINE_SIZE
+	.rept  CONFIG_SYS_CACHELINE_SIZE/4
+	.word 0
+	.endr
+#else
+	.rept 5
+	.word 0
+	.endr
+#endif
+END(omap_smc_sec_cpu1_args)