[PATCH v2 09/15] ARM: i.MX8M: add support to pass BL3x bl_params

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

Add support to handover the BL32 and BL33 entrypoints via the TF-A
struct::bl_params in arg0. This eliminates the requirement to share the
different load addresses between multiple binaries to lower the BSP
integration effort.

In addition to the entriespoints, this commit also adds the support to
pass the builtin barebox DTB to OP-TEE if enabled.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
 arch/arm/mach-imx/Kconfig | 16 ++++++++++
 arch/arm/mach-imx/atf.c   | 80 ++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 95 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index d244c5758073c0f2c683e500e0d4ed0a6bff2cb5..b3e6e944867e7bd0ce6f15a6d693de44590c809c 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -38,6 +38,22 @@ config ARCH_IMX_ATF
 	def_bool y
 	depends on ARCH_IMX8M || ARCH_IMX9
 
+config ARCH_IMX_ATF_PASS_BL_PARAMS
+	bool "Pass BL3x bl_params as arg0 to TF-A"
+	depends on ARCH_IMX_ATF
+	select ARM_ATF
+	select LIBFDT
+	help
+	  Enable this option if you are using an upstream TF-A that uses
+	  the struct::bl_params to handover all required BL32 and BL33
+	  information required to start the BL32 and BL33 image.
+
+	  Since upstream TF-A v2.12 all i.MX8M support this feature except for
+	  the i.MX8MQ.
+
+	  This option is required if the barebox DT should be passed to the
+	  BL32 firmware.
+
 config ARCH_IMX_ROMAPI
 	def_bool y
 	depends on ARCH_IMX8M || ARCH_IMX9
diff --git a/arch/arm/mach-imx/atf.c b/arch/arm/mach-imx/atf.c
index 11d26607bc2ea449402d9cb8e20fbb44f425989c..34893c3a04616a9fbf2648a58940bec793ae04c8 100644
--- a/arch/arm/mach-imx/atf.c
+++ b/arch/arm/mach-imx/atf.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
+#include <asm/atf_common.h>
 #include <asm/sections.h>
 #include <common.h>
 #include <firmware.h>
@@ -18,6 +19,7 @@
 #include <mach/imx/ele.h>
 #include <mach/imx/xload.h>
 #include <mach/imx/snvs.h>
+#include <pbl.h>
 
 static void imx_adjust_optee_memory(void **bl32, void **bl32_image, size_t *bl32_size)
 {
@@ -37,6 +39,68 @@ static void imx_adjust_optee_memory(void **bl32, void **bl32_image, size_t *bl32
 	*bl32_image += sizeof(*hdr);
 }
 
+static __noreturn void bl31_via_bl_params(void *bl31, void *bl32, void *bl33,
+					  void *fdt)
+{
+	struct bl2_to_bl31_params_mem_v2 *params;
+
+	/* Prepare bl_params for BL32 */
+	params = bl2_plat_get_bl31_params_v2((uintptr_t)bl32,
+			(uintptr_t)bl33, (uintptr_t)fdt);
+
+	pr_debug("Jump to BL31 with bl-params (%s BL32-FDT)\n",
+		 fdt ? "including" : "excluding");
+	/*
+	 * Start BL31 without passing the FDT via x1 since the mainline
+	 * TF-A doesn't support it yet.
+	 */
+	bl31_entry_v2((uintptr_t)bl31, &params->bl_params, NULL);
+
+	__builtin_unreachable();
+}
+
+static __noreturn void start_bl31_via_bl_params(void *bl31, void *bl32,
+						void *bl33, void *fdt)
+{
+	unsigned long mem_base = MX8M_DDR_CSD1_BASE_ADDR;
+	unsigned long mem_sz;
+	unsigned int bufsz = 0;
+	int error;
+	u8 *buf;
+
+	if (!fdt)
+		bl31_via_bl_params(bl31, bl32, bl33, NULL);
+
+	buf = imx_scratch_get_fdt(&bufsz);
+	if (IS_ERR_OR_NULL(buf)) {
+		if (!buf)
+			pr_debug("No FDT scratch mem configured, continue without FDT\n");
+		else
+			pr_warn("Failed to get FDT scratch mem, continue without FDT\n");
+		bl31_via_bl_params(bl31, bl32, bl33, NULL);
+	}
+
+	error = pbl_load_fdt(fdt, buf, bufsz);
+	if (error) {
+		pr_warn("Failed to load FDT, continue without FDT\n");
+		bl31_via_bl_params(bl31, bl32, bl33, NULL);
+	}
+
+	if (cpu_is_mx8mn())
+		mem_sz = imx8m_ddrc_sdram_size(16);
+	else
+		mem_sz = imx8m_ddrc_sdram_size(32);
+
+	fdt = buf;
+	error = fdt_fixup_mem(fdt, &mem_base, &mem_sz, 1);
+	if (error) {
+		pr_warn("Failed to fixup FDT memory node, continue without FDT\n");
+		bl31_via_bl_params(bl31, bl32, bl33, NULL);
+	}
+
+	bl31_via_bl_params(bl31, bl32, bl33, fdt);
+}
+
 /**
  * imx8m_tfa_start_bl31 - Load TF-A BL31 blob and transfer control to it
  *
@@ -122,7 +186,21 @@ imx8m_tfa_start_bl31(const void *tfa_bin, size_t tfa_size, void *tfa_dest,
 	asm volatile("msr sp_el2, %0" : :
 		     "r" (tfa_dest - 16) :
 		     "cc");
-	bl31();
+
+	/*
+	 * If enabled the bl_params are passed via x0 to the TF-A, except for
+	 * the i.MX8MQ which doesn't support bl_params yet.
+	 * Passing the bl_params must be explicit enabled to be backward
+	 * compatible with downstream TF-A versions, which may have problems
+	 * with the bl_params.
+	 */
+	if (!IS_ENABLED(CONFIG_ARCH_IMX_ATF_PASS_BL_PARAMS) || cpu_is_mx8mq()) {
+		pr_debug("Jump to BL31 without bl-params\n");
+		bl31();
+	} else {
+		start_bl31_via_bl_params(bl31, bl32, bl33, fdt);
+	}
+
 	__builtin_unreachable();
 }
 

-- 
2.47.3