On 6/9/26 6:52 PM, Alexey Charkov wrote:
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.
TFA
+/* BL33 defaults to U-Boot unless Falcon mode selects Linux. */
+static int spl_atf_bl33_os;
+
Can we avoid this global static variable ?
/* 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) */
That seems a bit inconsistent, and not quite right. Do you know where
U-Boot expects primary CPU ID in x0 exactly ? Which part of U-Boot code
depends on it ?
- 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();
[...]
@@ -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.
That does not seem correct, if Linux cannot be resolved, then the system
should stop booting, falling back into a bootloader could be security
risk. There is a "recovery" boot weak symbol function, which can be used
to start fallback bootloader, but that has to be deliberately
implemented and triggered by the user e.g. by holding a button down.
