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Commit 96a8123e authored by Rafał Miłecki's avatar Rafał Miłecki Committed by Ralf Baechle
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MIPS: BCM47XX: Slightly clean memory detection 



Patch was tested on devices with 64 MiB and 256 MiB of RAM.
It documents every part nicely and drops this hacky part of code:
max = off | ((128 << 20) - 1);

Signed-off-by: default avatarRafał Miłecki <zajec5@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: https://patchwork.linux-mips.org/patch/6808/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent d8ce7593

arch/mips/bcm47xx/prom.c

+11 −8
Original line number Diff line number Diff line
@@ -69,15 +69,18 @@ static __init void prom_init_mem(void) 
	 * BCM47XX uses 128MB for addressing the ram, if the system contains

	 * less that that amount of ram it remaps the ram more often into the

	 * available space.

	 * Accessing memory after 128MB will cause an exception.

	 * max contains the biggest possible address supported by the platform.

	 * If the method wants to try something above we assume 128MB ram.

	 */

	off = (unsigned long)prom_init;

	max = off | ((128 << 20) - 1);

	for (mem = (1 << 20); mem < (128 << 20); mem += (1 << 20)) {

		if ((off + mem) > max) {

			mem = (128 << 20);



	/* Physical address, without mapping to any kernel segment */

	off = CPHYSADDR((unsigned long)prom_init);



	/* Accessing memory after 128 MiB will cause an exception */

	max = 128 << 20;



	for (mem = 1 << 20; mem < max; mem += 1 << 20) {

		/* Loop condition may be not enough, off may be over 1 MiB */

		if (off + mem >= max) {

			mem = max;

			printk(KERN_DEBUG "assume 128MB RAM\n");

			break;

		}