[LinuxBIOS] v3: documentation fixes
Jordan Crouse
jordan.crouse at amd.com
Thu Nov 15 01:32:25 CET 2007
I think printk is always available - any previous printk pain has been
(finally) resolved.
On 15/11/07 01:25 +0100, Carl-Daniel Hailfinger wrote:
> Fix code comments/documentation related to printk.
> Sprinkle TODOs all over obviously wrong comments.
> Document possible execution flow alternatives for later investigation.
>
> Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
>
> ---
>
> Index: LinuxBIOSv3/mainboard/adl/msm800sev/stage1.c
> ===================================================================
> --- LinuxBIOSv3/mainboard/adl/msm800sev/stage1.c (Revision 509)
> +++ LinuxBIOSv3/mainboard/adl/msm800sev/stage1.c (Arbeitskopie)
> @@ -51,5 +51,5 @@
> */
> cs5536_disable_internal_uart();
> w83627hf_enable_serial(0x2e, SERIAL_DEV, SERIAL_IOBASE);
> - printk(BIOS_DEBUG, "Done %s\n", __FUNCTION__);
> + /* We can NOT yet use printk! */
> }
> Index: LinuxBIOSv3/mainboard/emulation/qemu-x86/stage1.c
> ===================================================================
> --- LinuxBIOSv3/mainboard/emulation/qemu-x86/stage1.c (Revision 509)
> +++ LinuxBIOSv3/mainboard/emulation/qemu-x86/stage1.c (Arbeitskopie)
> @@ -17,7 +17,7 @@
> * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
> */
>
> -/* no printk allowed until hardware is ready; hardware is ready */
> +/* no printk allowed until hardware is ready; hardware is not yet ready */
>
> /**
> * start up hardware needed for stage1
> Index: LinuxBIOSv3/lib/stage2.c
> ===================================================================
> --- LinuxBIOSv3/lib/stage2.c (Revision 509)
> +++ LinuxBIOSv3/lib/stage2.c (Arbeitskopie)
> @@ -37,7 +37,10 @@
> *
> * Device Enumeration: in the dev_enumerate() phase.
> *
> - * TODO: Check whether this documentation is still correct. Improve it.
> + * TODO:
> + * - Check whether this documentation is still correct. Improve it.
> + * - Replace magic constants by #defines.
> + * - Fix POST codes. Right now phases 1+3 have POST 0x30, phases 2+4 have 0x40.
> */
> int stage2(void)
> {
> @@ -54,13 +57,19 @@
>
> post_code(0x20);
>
> - /* TODO: Explain why we use printk here although it is impossible */
> + /* TODO: Explain why we use printk here although it is claimed to be
> + * impossible according to the documentation. The "has to be done
> + * before printk can be used" comment below seems to suggest the same.
> + * However, we already enable serial in arch/x86/stage1.c:stage1_main()
> + * when we call hardware_stage1(); uart_init(); console_init();
> + */
> printk(BIOS_NOTICE, console_test);
>
> dev_init();
>
> /* Console init, also ANYTHING that has to be done
> - * before printk can be used.
> + * before printk can be used.
> + * FIXME: This comment contradicts the comment above.
> */
> post_code(0x30);
> dev_phase1();
> Index: LinuxBIOSv3/arch/x86/stage1.c
> ===================================================================
> --- LinuxBIOSv3/arch/x86/stage1.c (Revision 509)
> +++ LinuxBIOSv3/arch/x86/stage1.c (Arbeitskopie)
> @@ -108,8 +108,12 @@
>
> //
> uart_init(); // initialize serial port
> - console_init(); // print banner
>
> + /* Exactly from now on we can use printk. Celebrate this by printing
> + * a LB banner.
> + */
> + console_init();
> +
> if (bist!=0) {
> printk(BIOS_INFO, "BIST FAILED: %08x", bist);
> die("");
> @@ -133,6 +137,30 @@
> // FIXME check integrity
>
>
> + /* Right now we have to fit
> + * initram stack
> + * lar stack
> + * into cache during CAR. IFF we can be sure that
> + * nrv2b stack
> + * initram code
> + * lar code
> + * fit into cache as well, we can compress initram code and lar code,
> + * leading to potential speedup (due to having to read less from ROM)
> + * and size savings. However, initram code and lar code would have
> + * to be compiled as PIC code, not as XIP code.
> + *
> + * Suggested code flow:
> + * unrv2b(lar_code);
> + * ...
> + * execute_in_car(&archive, "normal/initram");
> + *
> + * A less complicated (from a linker perspective) variant would
> + * compress only initram code, but it is not clear whether all hardware
> + * can run code from cache while training memory in the area designated
> + * by the cache. Some processors might drop cache contents in that case,
> + * rendering the ideas above mostly moot.
> + * TODO: Check how this works in the real world.
> + */
> // find first initram
> if (check_normal_boot_flag()) {
> printk(BIOS_DEBUG, "Choosing normal boot.\n");
>
>
>
> --
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> linuxbios at linuxbios.org
> http://www.linuxbios.org/mailman/listinfo/linuxbios
>
>
--
Jordan Crouse
Systems Software Development Engineer
Advanced Micro Devices, Inc.
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