[LinuxBIOS] v3: documentation fixes

[Jordan Crouse]

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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> 
> 

-- 
Jordan Crouse
Systems Software Development Engineer 
Advanced Micro Devices, Inc.