This patch enables/disables the PPC440GX L2 cache based on
errata which prevents reliable operation on certain CPU
revisions and speed grades.
Signed-off-by: Eugene Surovegin <ebs at ebshome.net>
Signed-off-by: Matt Porter <mporter at kernel.crashing.org>
===== arch/ppc/platforms/4xx/ocotea.c 1.7 vs edited =====
--- 1.7/arch/ppc/platforms/4xx/ocotea.c 2004-10-08 18:57:01 -07:00
+++ edited/arch/ppc/platforms/4xx/ocotea.c 2004-10-08 19:46:25 -07:00
@@ -81,7 +81,7 @@
{
seq_printf(m, "vendor\t\t: IBM\n");
seq_printf(m, "machine\t\t: PPC440GX EVB (Ocotea)\n");
-
+ ibm440gx_show_cpuinfo(m);
return 0;
}
@@ -299,15 +299,6 @@
mtspr(SPRN_DBCR0, (DBCR0_TDE | DBCR0_IDM));
#endif
- /*
- * Determine various clocks.
- * To be completely correct we should get SysClk
- * from FPGA, because it can be changed by on-board switches
- * --ebs
- */
- ibm440gx_get_clocks(&clocks, 33333333, 6 * 1843200);
- ocp_sys_info.opb_bus_freq = clocks.opb;
-
/* Setup TODC access */
TODC_INIT(TODC_TYPE_DS1743,
0,
@@ -350,8 +341,17 @@
if (r3)
__res = *(bd_t *)(r3 + KERNELBASE);
- /* Disable L2-Cache due to hardware issues */
- ibm440gx_l2c_disable();
+ /*
+ * Determine various clocks.
+ * To be completely correct we should get SysClk
+ * from FPGA, because it can be changed by on-board switches
+ * --ebs
+ */
+ ibm440gx_get_clocks(&clocks, 33333333, 6 * 1843200);
+ ocp_sys_info.opb_bus_freq = clocks.opb;
+
+ /* Disable L2-Cache on broken hardware, enable it otherwise */
+ ibm440gx_l2c_setup(&clocks);
ibm44x_platform_init();
===== arch/ppc/syslib/ibm440gx_common.c 1.1 vs edited =====
--- 1.1/arch/ppc/syslib/ibm440gx_common.c 2004-05-14 19:00:24 -07:00
+++ edited/arch/ppc/syslib/ibm440gx_common.c 2004-10-08 19:35:02 -07:00
@@ -171,6 +171,19 @@
asm volatile ("sync; isync" ::: "memory");
}
+void __init ibm440gx_l2c_setup(struct ibm44x_clocks* p)
+{
+ /* Disable L2C on rev.A, rev.B and 800MHz version of rev.C,
+ enable it on all other revisions
+ */
+ u32 pvr = mfspr(PVR);
+ if (pvr == PVR_440GX_RA || pvr == PVR_440GX_RB ||
+ (pvr == PVR_440GX_RC && p->cpu > 667000000))
+ ibm440gx_l2c_disable();
+ else
+ ibm440gx_l2c_enable();
+}
+
int __init ibm440gx_get_eth_grp(void)
{
return (SDR_READ(DCRN_SDR_PFC1) & DCRN_SDR_PFC1_EPS) >>
DCRN_SDR_PFC1_EPS_SHIFT;
===== arch/ppc/syslib/ibm440gx_common.h 1.1 vs edited =====
--- 1.1/arch/ppc/syslib/ibm440gx_common.h 2004-05-14 19:00:24 -07:00
+++ edited/arch/ppc/syslib/ibm440gx_common.h 2004-10-08 19:36:03 -07:00
@@ -4,7 +4,7 @@
* PPC440GX system library
*
* Eugene Surovegin <eugene.surovegin at zultys.com> or <ebs at ebshome.net>
- * Copyright (c) 2003 Zultys Technologies
+ * Copyright (c) 2003, 2004 Zultys Technologies
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
@@ -36,6 +36,9 @@
/* Disable L2 cache */
void ibm440gx_l2c_disable(void) __init;
+
+/* Enable/disable L2 cache for a particular chip revision */
+void ibm440gx_l2c_setup(struct ibm44x_clocks*) __init;
/* Get Ethernet Group */
int ibm440gx_get_eth_grp(void) __init;
