The following patch adds code to the "simple" bootloader to disable
the ethernet controller on the Walnut board before booting the
kernel. This is necessary on the Walnut I have, at least, or the EMAC
has a tendency to DMA broadcast packets into the kernel text.
diff -urN ../linuxppc_2_4_devel/arch/ppc/boot/simple/embed_config.c
linux-bungo/arch/ppc/boot/simple/embed_config.c
--- ../linuxppc_2_4_devel/arch/ppc/boot/simple/embed_config.c Fri Aug 31
13:08:41 2001
+++ linux-bungo/arch/ppc/boot/simple/embed_config.c Thu Sep 6 11:25:24 2001
@@ -638,6 +638,8 @@
*/
#define BOARD_INFO_VECTOR 0xFFFE0B50
+#define PPC405_EM0MR0_ADDR 0xEF600800;
+
void
embed_config(bd_t **bdp)
{
@@ -646,6 +648,7 @@
bd_t *bd, *walnut_bd;
bd_t *(*get_board_info)(void) =
(bd_t *(*)(void))(*(unsigned long *)BOARD_INFO_VECTOR);
+ volatile u32 *em0mr0 = (volatile u32 *)PPC405_EM0MR0_ADDR;
bd = &bdinfo;
*bdp = bd;
@@ -668,5 +671,14 @@
bd->bi_busfreq = 100000000;
bd->bi_pci_busfreq = 66666666;
}
+
+ /* Now turn of the EMAC - otherwise it has a tendency to DMA
+ crap into the kernel text */
+ mtdcr(DCRN_MALCR, MALCR_MMSR); /* 1st reset MAL */
+
+ while (mfdcr(DCRN_MALCR) & MALCR_MMSR)
+ ; /* wait for the reset */
+
+ *em0mr0 = 0x20000000; /* then reset EMAC */
}
#endif
--
David Gibson | For every complex problem there is a
david at gibson.dropbear.id.au | solution which is simple, neat and
| wrong. -- H.L. Mencken
http://www.ozlabs.org/people/dgibson
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