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Diffstat (limited to 'docs/porting-guide.md')
| -rw-r--r-- | docs/porting-guide.md | 43 |
1 files changed, 36 insertions, 7 deletions
diff --git a/docs/porting-guide.md b/docs/porting-guide.md index f0adf570..3b6e242b 100644 --- a/docs/porting-guide.md +++ b/docs/porting-guide.md @@ -76,12 +76,12 @@ either mandatory or optional. A platform port must enable the Memory Management Unit (MMU) as well as the instruction and data caches for each BL stage. Setting up the translation tables is the responsibility of the platform port because memory maps differ -across platforms. A memory translation library (see `lib/aarch64/xlat_helpers.c` -and `lib/aarch64/xlat_tables.c`) is provided to help in this setup. Note that -although this library supports non-identity mappings, this is intended only for -re-mapping peripheral physical addresses and allows platforms with high I/O -addresses to reduce their virtual address space. All other addresses -corresponding to code and data must currently use an identity mapping. +across platforms. A memory translation library (see `lib/aarch64/xlat_tables.c`) +is provided to help in this setup. Note that although this library supports +non-identity mappings, this is intended only for re-mapping peripheral physical +addresses and allows platforms with high I/O addresses to reduce their virtual +address space. All other addresses corresponding to code and data must currently +use an identity mapping. In ARM standard platforms, each BL stage configures the MMU in the platform-specific architecture setup function, `blX_plat_arch_setup()`, and uses @@ -633,6 +633,35 @@ retrieved from the platform. The function also reports extra information related to the ROTPK in the flags parameter. +### Function: plat_get_nv_ctr() + + Argument : void *, unsigned int * + Return : int + +This function is mandatory when Trusted Board Boot is enabled. It returns the +non-volatile counter value stored in the platform in the second argument. The +cookie in the first argument may be used to select the counter in case the +platform provides more than one (for example, on platforms that use the default +TBBR CoT, the cookie will correspond to the OID values defined in +TRUSTED_FW_NVCOUNTER_OID or NON_TRUSTED_FW_NVCOUNTER_OID). + +The function returns 0 on success. Any other value means the counter value could +not be retrieved from the platform. + + +### Function: plat_set_nv_ctr() + + Argument : void *, unsigned int + Return : int + +This function is mandatory when Trusted Board Boot is enabled. It sets a new +counter value in the platform. The cookie in the first argument may be used to +select the counter (as explained in plat_get_nv_ctr()). + +The function returns 0 on success. Any other value means the counter value could +not be updated. + + 2.3 Common mandatory modifications --------------------------------- @@ -1259,7 +1288,7 @@ later Bootloader stages with MMU off ### Function : plat_get_ns_image_entrypoint() [mandatory] Argument : void - Return : unsigned long + Return : uintptr_t As previously described, BL2 is responsible for arranging for control to be passed to a normal world BL image through BL31. This function returns the |