[PATCH 1/4] spl: atf: support Linux as BL33 with ATF

[Alexey Charkov]

Modern SoCs such as Rockchip RK3576 need ATF to be running to provide
firmware services to the OS.

Enable the ATF boot flow to allow using Linux as BL33 (including its
calling convention) to facilitate Falcon mode boot on such SoCs.

Signed-off-by: Alexey Charkov <alchark at flipper.net>
---
 common/spl/spl_atf.c | 45 +++++++++++++++++++++++++++++++--------------
 1 file changed, 31 insertions(+), 14 deletions(-)

diff --git a/common/spl/spl_atf.c b/common/spl/spl_atf.c
index 8bc5db773950..1f030cab0928 100644
--- a/common/spl/spl_atf.c
+++ b/common/spl/spl_atf.c
@@ -17,6 +17,9 @@
 #include <spl.h>
 #include <asm/cache.h>
 
+/* BL33 defaults to U-Boot unless Falcon mode selects Linux. */
+static int spl_atf_bl33_os;
+
 /* Holds all the structures we need for bl31 parameter passing */
 struct bl2_to_bl31_params_mem {
 	struct bl31_params bl31_params;
@@ -87,8 +90,11 @@ struct bl31_params *bl2_plat_get_bl31_params_default(ulong bl32_entry,
 	SET_PARAM_HEAD(bl33_ep_info, ATF_PARAM_EP, ATF_VERSION_1,
 		       ATF_EP_NON_SECURE);
 
-	/* BL33 expects to receive the primary CPU MPID (through x0) */
-	bl33_ep_info->args.arg0 = 0xffff & read_mpidr();
+	/* Linux-at-BL33 expects DTB in x0, U-Boot expects primary CPU MPID in x0. */
+	if (IS_ENABLED(CONFIG_SPL_OS_BOOT) && spl_atf_bl33_os == IH_OS_LINUX)
+		bl33_ep_info->args.arg0 = fdt_addr;
+	else
+		bl33_ep_info->args.arg0 = 0xffff & read_mpidr();
 	bl33_ep_info->pc = bl33_entry;
 	bl33_ep_info->spsr = SPSR_64(MODE_EL2, MODE_SP_ELX,
 				     DISABLE_ALL_EXECPTIONS);
@@ -162,8 +168,11 @@ struct bl_params *bl2_plat_get_bl31_params_v2_default(ulong bl32_entry,
 	SET_PARAM_HEAD(bl_params_node->ep_info, ATF_PARAM_EP,
 		       ATF_VERSION_2, ATF_EP_NON_SECURE);
 
-	/* BL33 expects to receive the primary CPU MPID (through x0) */
-	bl_params_node->ep_info->args.arg0 = 0xffff & read_mpidr();
+	/* Linux-at-BL33 expects DTB in x0, U-Boot expects primary CPU MPID in x0. */
+	if (IS_ENABLED(CONFIG_SPL_OS_BOOT) && spl_atf_bl33_os == IH_OS_LINUX)
+		bl_params_node->ep_info->args.arg0 = fdt_addr;
+	else
+		bl_params_node->ep_info->args.arg0 = 0xffff & read_mpidr();
 	bl_params_node->ep_info->pc = bl33_entry;
 	bl_params_node->ep_info->spsr = SPSR_64(MODE_EL2, MODE_SP_ELX,
 						DISABLE_ALL_EXECPTIONS);
@@ -189,7 +198,8 @@ static inline void raw_write_daif(unsigned int daif)
 typedef void __noreturn (*atf_entry_t)(struct bl31_params *params, void *plat_params);
 
 static void __noreturn bl31_entry(ulong bl31_entry, ulong bl32_entry,
-				  ulong bl33_entry, ulong fdt_addr)
+				  ulong bl33_entry, ulong fdt_addr,
+				  ulong plat_param)
 {
 	atf_entry_t  atf_entry = (atf_entry_t)bl31_entry;
 	void *bl31_params;
@@ -206,7 +216,7 @@ static void __noreturn bl31_entry(ulong bl31_entry, ulong bl32_entry,
 	if (!CONFIG_IS_ENABLED(SYS_DCACHE_OFF))
 		dcache_disable();
 
-	atf_entry(bl31_params, (void *)fdt_addr);
+	atf_entry(bl31_params, (void *)plat_param);
 }
 
 static int spl_fit_images_find(void *blob, int os)
@@ -255,7 +265,7 @@ void __noreturn spl_invoke_atf(struct spl_image_info *spl_image)
 {
 	ulong  bl32_entry = 0;
 	ulong  bl33_entry = CONFIG_TEXT_BASE;
-	void *blob = spl_image->fdt_addr;
+	void *blob = spl_image_fdt_addr(spl_image);
 	ulong platform_param = (ulong)blob;
 	int node;
 
@@ -269,15 +279,22 @@ void __noreturn spl_invoke_atf(struct spl_image_info *spl_image)
 		bl32_entry = spl_fit_images_get_entry(blob, node);
 
 	/*
-	 * Find the U-Boot binary (in /fit-images) load addreess or
-	 * entry point (if different) and pass it as the BL3-3 entry
-	 * point.
-	 * This will need to be extended to support Falcon mode.
+	 * Find BL33 entry point. In Falcon mode, prefer Linux when requested.
+	 * Fall back to U-Boot if Linux cannot be resolved.
 	 */
+	node = -FDT_ERR_NOTFOUND;
+	spl_atf_bl33_os = IH_OS_U_BOOT;
+	if (IS_ENABLED(CONFIG_SPL_OS_BOOT) && !spl_start_uboot())
+		node = spl_fit_images_find(blob, IH_OS_LINUX);
 
-	node = spl_fit_images_find(blob, IH_OS_U_BOOT);
-	if (node >= 0)
+	if (node >= 0) {
 		bl33_entry = spl_fit_images_get_entry(blob, node);
+		spl_atf_bl33_os = IH_OS_LINUX;
+	} else {
+		node = spl_fit_images_find(blob, IH_OS_U_BOOT);
+		if (node >= 0)
+			bl33_entry = spl_fit_images_get_entry(blob, node);
+	}
 
 	/*
 	 * If ATF_NO_PLATFORM_PARAM is set, we override the platform
@@ -293,5 +310,5 @@ void __noreturn spl_invoke_atf(struct spl_image_info *spl_image)
 	 * using similar logic.
 	 */
 	bl31_entry(spl_image->entry_point, bl32_entry,
-		   bl33_entry, platform_param);
+		   bl33_entry, (ulong)blob, platform_param);
 }

-- 
2.53.0