diff options
| author | Simon Glass | 2019-09-25 08:11:44 -0600 |
|---|---|---|
| committer | Bin Meng | 2019-10-08 13:57:36 +0800 |
| commit | 08deb6d36f0a830181a3acce5eaece9431a828c0 (patch) | |
| tree | 5b60cec6a9ae945d12232e164fa177497d1b8fa3 | |
| parent | 6172e94c3c4729347624626d71e4eaf96ff9dcb9 (diff) | |
x86: Add more comments to the start-up code
The full start-up sequence (TPL->SPL->U-Boot) can be a bit confusing since
each phase has its own 'start' file. Add comments to explain this.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
| -rw-r--r-- | arch/x86/cpu/start.S | 12 | ||||
| -rw-r--r-- | arch/x86/cpu/start_from_spl.S | 5 | ||||
| -rw-r--r-- | arch/x86/cpu/start_from_tpl.S | 3 |
3 files changed, 17 insertions, 3 deletions
diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S index 9b763942743..01524635e9c 100644 --- a/arch/x86/cpu/start.S +++ b/arch/x86/cpu/start.S @@ -2,6 +2,18 @@ /* * U-Boot - x86 Startup Code * + * This is always the first code to run from the U-Boot source. To spell it out: + * + * 1. When TPL (Tertiary Program Loader) is enabled, the boot flow is + * TPL->SPL->U-Boot and this file is used for TPL. Then start_from_tpl.S is used + * for SPL and start_from_spl.S is used for U-Boot proper. + * + * 2. When SPL (Secondary Program Loader) is enabled, but not TPL, the boot + * flow is SPL->U-Boot and this file is used for SPL. Then start_from_spl.S is + * used for U-Boot proper. + * + * 3. When neither TPL nor SPL is used, this file is used for U-Boot proper. + * * (C) Copyright 2008-2011 * Graeme Russ, <graeme.russ@gmail.com> * diff --git a/arch/x86/cpu/start_from_spl.S b/arch/x86/cpu/start_from_spl.S index 4d4e5d0758d..a73b4d7c459 100644 --- a/arch/x86/cpu/start_from_spl.S +++ b/arch/x86/cpu/start_from_spl.S @@ -1,7 +1,8 @@ /* SPDX-License-Identifier: GPL-2.0+ */ /* - * 32-bit x86 Startup Code when running from SPL - * + * 32-bit x86 Startup Code when running from SPL. This is the startup code in + * U-Boot proper, when SPL is used. + * Copyright 2018 Google, Inc * Written by Simon Glass <sjg@chromium.org> */ diff --git a/arch/x86/cpu/start_from_tpl.S b/arch/x86/cpu/start_from_tpl.S index 44b5363a685..9a4974a5f1b 100644 --- a/arch/x86/cpu/start_from_tpl.S +++ b/arch/x86/cpu/start_from_tpl.S @@ -1,6 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0+ */ /* - * 32-bit x86 Startup Code when running from TPL + * 32-bit x86 Startup Code when running from TPL. This is the startup code in + * SPL, when TPL is used. * * Copyright 2018 Google, Inc * Written by Simon Glass <sjg@chromium.org> |