[PATCH v2 13/15] ARM: i.MX8M: Pass optional OP-TEE overlay to barebox

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

This commit adds the support to pass the optional OP-TEE overlay from
pbl to barebox for all i.MX8M SoCs.

There is no difference between ARMv7 and ARMv8, therefore the helper
name to pass the overlay is generic.

That being said, on ARMv8 it's required to use the
ARCH_IMX_ATF_PASS_BL_PARAMS mechanism, else the devicetree location
can't be passed to OP-TEE. Therefore a sanity check for ARMv8 is added.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
 arch/arm/mach-imx/esdctl.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/arch/arm/mach-imx/esdctl.c b/arch/arm/mach-imx/esdctl.c
index e4b4ca561094e2dac99f475b93efc8fc7e962d9e..abd2cb29f01f19b19e9285b513fc289a3fa60305 100644
--- a/arch/arm/mach-imx/esdctl.c
+++ b/arch/arm/mach-imx/esdctl.c
@@ -877,6 +877,45 @@ upper_or_coalesced_range(unsigned long base0, unsigned long size0,
 	}
 }
 
+static void imx_optee_handoff_overlay(void)
+{
+	unsigned int early_fdt_sz;
+	u8 *early_fdt;
+
+	/*
+	 * On ARMv8 i.MX SoCs CONFIG_ARCH_IMX_ATF_PASS_BL_PARAMS must be enabled
+	 * else no FDT is passed to OP-TEE.
+	 */
+	if (IS_ENABLED(CONFIG_CPU_V8) &&
+	    !IS_ENABLED(CONFIG_ARCH_IMX_ATF_PASS_BL_PARAMS))
+		return;
+
+	early_fdt = imx_scratch_get_fdt(&early_fdt_sz);
+	if (IS_ERR(early_fdt)) {
+		pr_warn("Failed to get FDT scratch mem, skip register OP-TEE DTBO\n");
+		return;
+	}
+
+	/* SCRATCH_FDT_SIZE == 0 if no early FDT was required */
+	if (!early_fdt)
+		return;
+
+	/*
+	 * OP-TEE DT handling is really cumbersome. In case an external DT was
+	 * supplied, OP-TEE re-use this DT and appends overlays if enabled.
+	 *
+	 * Register the whole early FDT as overlay and let the barebox common
+	 * code extract the __fragment__'s from the early FDT which should be
+	 * faster than doing it here manually via libfdt and no MMU.
+	 *
+	 * Note: This assumes that OP-TEE is the only one adding __fragment__'s.
+	 * This is always the case on ARMv7, but on ARMv8 the BL31 (TF-A) could
+	 * add __fragment__'s too. Since the barebox i.MX port doesn't pass the
+	 * FDT to the TF-A this is fine for now.
+	 */
+	optee_handoff_overlay(early_fdt, early_fdt_sz);
+}
+
 void __noreturn imx1_barebox_entry(void *boarddata)
 {
 	unsigned long base, size;
@@ -1020,6 +1059,7 @@ static void __noreturn imx8m_barebox_entry(void *boarddata, unsigned buswidth)
 {
 	imx8m_init_scratch_space(buswidth, false);
 	optee_set_membase(imx_scratch_get_optee_hdr());
+	imx_optee_handoff_overlay();
 	barebox_arm_entry(MX8M_DDR_CSD1_BASE_ADDR,
 			  imx8m_barebox_earlymem_size(buswidth), boarddata);
 }

-- 
2.47.3