[PATCH 14/23] ARM: i.MX: scratch: add OP-TEE FDTO support

[Marco Felsch <m.felsch@pengutronix.de>]

OP-TEE has the support to write DTB overlay fragments if enabled via
OP-TEE config switch CFG_EXTERNAL_DTB_OVERLAY.

The overlay fragments are added to the exisiting DTB if OP-TEE was
started with a DTB provided via arg2 or written to a stand-alone DTB
overlay.

This adds a dedicated storage slot which can be passed to OP-TEE or be
used by barebox to extract the added overlay fragment into it.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
 arch/arm/mach-imx/scratch.c | 14 ++++++++++++++
 common/Kconfig              | 10 ++++++++++
 include/mach/imx/scratch.h  |  1 +
 3 files changed, 25 insertions(+)

diff --git a/arch/arm/mach-imx/scratch.c b/arch/arm/mach-imx/scratch.c
index 9c0f1c09c4e0b863d8c95888db7cf0518f698d53..393d3a976fec28a94e4515c82d309eb7338cdd4c 100644
--- a/arch/arm/mach-imx/scratch.c
+++ b/arch/arm/mach-imx/scratch.c
@@ -18,6 +18,7 @@ struct imx_scratch_space {
 	struct optee_header optee_hdr;
 	/* FDT needs an 8 byte alignment */
 	u8 fdt[CONFIG_SCRATCH_FDT_SIZE] __aligned(8);
+	u8 optee_fdto[CONFIG_SCRATCH_FDTO_SIZE] __aligned(8);
 };
 static_assert(sizeof(struct imx_scratch_space) <= CONFIG_SCRATCH_SIZE);
 
@@ -108,3 +109,16 @@ void imx_scratch_get_fdt(void **fdt, unsigned int *fdt_sz)
 	*fdt = scratch->fdt;
 	*fdt_sz = sizeof(scratch->fdt);
 }
+
+void imx_scratch_get_optee_fdto(void **fdto, unsigned int *fdto_sz)
+{
+	if (!scratch) {
+		if (IN_PBL)
+			return;
+		else
+			scratch = (void *)arm_mem_scratch_get();
+	}
+
+	*fdto = scratch->optee_fdto;
+	*fdto_sz = sizeof(scratch->optee_fdto);
+}
diff --git a/common/Kconfig b/common/Kconfig
index 3f394416c3c376d1cf842472803a47462bb012ed..2e4f4d6713575dbdabf24da8953978b40ddf5604 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -318,6 +318,16 @@ config SCRATCH_FDT_SIZE
 	  This option should match the OP-TEE's CFG_DTB_MAX_SIZE configuration
 	  if used by OP-TEE.
 
+config SCRATCH_FDTO_SIZE
+	hex
+	default 0x0
+	default 0x4000 if PBL_EARLY_FDT_LOAD
+	prompt "Scratch FDTO size"
+	help
+	  The size of possible FDT overlay areas used by BL3x binaries to store
+	  runtime generated overlays. Can be 0x0 if early FDT support is not
+	  requied e.g. during BL31 and BL32 stage.
+
 config MALLOC_ALIGNMENT
 	hex
 	default 8
diff --git a/include/mach/imx/scratch.h b/include/mach/imx/scratch.h
index 43bf55de48099f1662cd4331620a93303d4dd710..a9745a95732dd961dcae83ec46c3eaa078d62a16 100644
--- a/include/mach/imx/scratch.h
+++ b/include/mach/imx/scratch.h
@@ -15,6 +15,7 @@ const struct optee_header *imx_scratch_get_optee_hdr(void);
 void imx_scratch_save_optee_hdr(const struct optee_header *hdr);
 
 void imx_scratch_get_fdt(void **fdt, unsigned int *fdt_sz);
+void imx_scratch_get_optee_fdto(void **fdto, unsigned int *fdto_sz);
 
 #define imx8mq_init_scratch_space() imx8m_init_scratch_space(32, true)
 #define imx8mm_init_scratch_space() imx8m_init_scratch_space(32, true)

-- 
2.47.3