[POWERPC] 4xx: Add PPC4xx L2-cache support (440GX)

This patch adds support for the 256k L2 cache found on some IBM/AMCC
4xx PPC's. It introduces a common 4xx SoC file (sysdev/ppc4xx_soc.c)
which currently "only" adds the L2 cache init code. Other common 4xx
stuff can be added later here.

The L2 cache handling code is a copy of Eugene's code in arch/ppc
with small modifications.

Tested on AMCC Taishan 440GX.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

2 files changed, 190 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index 15f3e8527d77..851a0be71947 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_PPC_INDIRECT_PCI)	+= indirect_pci.o
 obj-$(CONFIG_PPC_I8259)		+= i8259.o
 obj-$(CONFIG_IPIC)		+= ipic.o
 obj-$(CONFIG_4xx)		+= uic.o
+obj-$(CONFIG_4xx_SOC)		+= ppc4xx_soc.o
 obj-$(CONFIG_XILINX_VIRTEX)	+= xilinx_intc.o
 obj-$(CONFIG_OF_RTC)		+= of_rtc.o
 ifeq ($(CONFIG_PCI),y)
diff --git a/arch/powerpc/sysdev/ppc4xx_soc.c b/arch/powerpc/sysdev/ppc4xx_soc.c
new file mode 100644
index 000000000000..4b8617e44314
--- /dev/null
+++ b/arch/powerpc/sysdev/ppc4xx_soc.c
@@ -0,0 +1,189 @@
+/*
+ * IBM/AMCC PPC4xx SoC setup code
+ *
+ * Copyright 2008 DENX Software Engineering, Stefan Roese <sr@denx.de>
+ *
+ * L2 cache routines cloned from arch/ppc/syslib/ibm440gx_common.c which is:
+ *   Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
+ *   Copyright (c) 2003 - 2006 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
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/stddef.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/of_platform.h>
+
+#include <asm/dcr.h>
+#include <asm/dcr-regs.h>
+
+static u32 dcrbase_l2c;
+
+/*
+ * L2-cache
+ */
+
+/* Issue L2C diagnostic command */
+static inline u32 l2c_diag(u32 addr)
+{
+	mtdcr(dcrbase_l2c + DCRN_L2C0_ADDR, addr);
+	mtdcr(dcrbase_l2c + DCRN_L2C0_CMD, L2C_CMD_DIAG);
+	while (!(mfdcr(dcrbase_l2c + DCRN_L2C0_SR) & L2C_SR_CC))
+		;
+
+	return mfdcr(dcrbase_l2c + DCRN_L2C0_DATA);
+}
+
+static irqreturn_t l2c_error_handler(int irq, void *dev)
+{
+	u32 sr = mfdcr(dcrbase_l2c + DCRN_L2C0_SR);
+
+	if (sr & L2C_SR_CPE) {
+		/* Read cache trapped address */
+		u32 addr = l2c_diag(0x42000000);
+		printk(KERN_EMERG "L2C: Cache Parity Error, addr[16:26] = 0x%08x\n",
+		       addr);
+	}
+	if (sr & L2C_SR_TPE) {
+		/* Read tag trapped address */
+		u32 addr = l2c_diag(0x82000000) >> 16;
+		printk(KERN_EMERG "L2C: Tag Parity Error, addr[16:26] = 0x%08x\n",
+		       addr);
+	}
+
+	/* Clear parity errors */
+	if (sr & (L2C_SR_CPE | L2C_SR_TPE)){
+		mtdcr(dcrbase_l2c + DCRN_L2C0_ADDR, 0);
+		mtdcr(dcrbase_l2c + DCRN_L2C0_CMD, L2C_CMD_CCP | L2C_CMD_CTE);
+	} else {
+		printk(KERN_EMERG "L2C: LRU error\n");
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int __init ppc4xx_l2c_probe(void)
+{
+	struct device_node *np;
+	u32 r;
+	unsigned long flags;
+	int irq;
+	const u32 *dcrreg;
+	u32 dcrbase_isram;
+	int len;
+	const u32 *prop;
+	u32 l2_size;
+
+	np = of_find_compatible_node(NULL, NULL, "ibm,l2-cache");
+	if (!np)
+		return 0;
+
+	/* Get l2 cache size */
+	prop = of_get_property(np, "cache-size", NULL);
+	if (prop == NULL) {
+		printk(KERN_ERR "%s: Can't get cache-size!\n", np->full_name);
+		of_node_put(np);
+		return -ENODEV;
+	}
+	l2_size = prop[0];
+
+	/* Map DCRs */
+	dcrreg = of_get_property(np, "dcr-reg", &len);
+	if (!dcrreg || (len != 4 * sizeof(u32))) {
+		printk(KERN_ERR "%s: Can't get DCR register base !",
+		       np->full_name);
+		of_node_put(np);
+		return -ENODEV;
+	}
+	dcrbase_isram = dcrreg[0];
+	dcrbase_l2c = dcrreg[2];
+
+	/* Get and map irq number from device tree */
+	irq = irq_of_parse_and_map(np, 0);
+	if (irq == NO_IRQ) {
+		printk(KERN_ERR "irq_of_parse_and_map failed\n");
+		of_node_put(np);
+		return -ENODEV;
+	}
+
+	/* Install error handler */
+	if (request_irq(irq, l2c_error_handler, IRQF_DISABLED, "L2C", 0) < 0) {
+		printk(KERN_ERR "Cannot install L2C error handler"
+		       ", cache is not enabled\n");
+		of_node_put(np);
+		return -ENODEV;
+	}
+
+	local_irq_save(flags);
+	asm volatile ("sync" ::: "memory");
+
+	/* Disable SRAM */
+	mtdcr(dcrbase_isram + DCRN_SRAM0_DPC,
+	      mfdcr(dcrbase_isram + DCRN_SRAM0_DPC) & ~SRAM_DPC_ENABLE);
+	mtdcr(dcrbase_isram + DCRN_SRAM0_SB0CR,
+	      mfdcr(dcrbase_isram + DCRN_SRAM0_SB0CR) & ~SRAM_SBCR_BU_MASK);
+	mtdcr(dcrbase_isram + DCRN_SRAM0_SB1CR,
+	      mfdcr(dcrbase_isram + DCRN_SRAM0_SB1CR) & ~SRAM_SBCR_BU_MASK);
+	mtdcr(dcrbase_isram + DCRN_SRAM0_SB2CR,
+	      mfdcr(dcrbase_isram + DCRN_SRAM0_SB2CR) & ~SRAM_SBCR_BU_MASK);
+	mtdcr(dcrbase_isram + DCRN_SRAM0_SB3CR,
+	      mfdcr(dcrbase_isram + DCRN_SRAM0_SB3CR) & ~SRAM_SBCR_BU_MASK);
+
+	/* Enable L2_MODE without ICU/DCU */
+	r = mfdcr(dcrbase_l2c + DCRN_L2C0_CFG) &
+		~(L2C_CFG_ICU | L2C_CFG_DCU | L2C_CFG_SS_MASK);
+	r |= L2C_CFG_L2M | L2C_CFG_SS_256;
+	mtdcr(dcrbase_l2c + DCRN_L2C0_CFG, r);
+
+	mtdcr(dcrbase_l2c + DCRN_L2C0_ADDR, 0);
+
+	/* Hardware Clear Command */
+	mtdcr(dcrbase_l2c + DCRN_L2C0_CMD, L2C_CMD_HCC);
+	while (!(mfdcr(dcrbase_l2c + DCRN_L2C0_SR) & L2C_SR_CC))
+		;
+
+	/* Clear Cache Parity and Tag Errors */
+	mtdcr(dcrbase_l2c + DCRN_L2C0_CMD, L2C_CMD_CCP | L2C_CMD_CTE);
+
+	/* Enable 64G snoop region starting at 0 */
+	r = mfdcr(dcrbase_l2c + DCRN_L2C0_SNP0) &
+		~(L2C_SNP_BA_MASK | L2C_SNP_SSR_MASK);
+	r |= L2C_SNP_SSR_32G | L2C_SNP_ESR;
+	mtdcr(dcrbase_l2c + DCRN_L2C0_SNP0, r);
+
+	r = mfdcr(dcrbase_l2c + DCRN_L2C0_SNP1) &
+		~(L2C_SNP_BA_MASK | L2C_SNP_SSR_MASK);
+	r |= 0x80000000 | L2C_SNP_SSR_32G | L2C_SNP_ESR;
+	mtdcr(dcrbase_l2c + DCRN_L2C0_SNP1, r);
+
+	asm volatile ("sync" ::: "memory");
+
+	/* Enable ICU/DCU ports */
+	r = mfdcr(dcrbase_l2c + DCRN_L2C0_CFG);
+	r &= ~(L2C_CFG_DCW_MASK | L2C_CFG_PMUX_MASK | L2C_CFG_PMIM
+	       | L2C_CFG_TPEI | L2C_CFG_CPEI | L2C_CFG_NAM | L2C_CFG_NBRM);
+	r |= L2C_CFG_ICU | L2C_CFG_DCU | L2C_CFG_TPC | L2C_CFG_CPC | L2C_CFG_FRAN
+		| L2C_CFG_CPIM | L2C_CFG_TPIM | L2C_CFG_LIM | L2C_CFG_SMCM;
+
+	/* Check for 460EX/GT special handling */
+	if (of_device_is_compatible(np, "ibm,l2-cache-460ex"))
+		r |= L2C_CFG_RDBW;
+
+	mtdcr(dcrbase_l2c + DCRN_L2C0_CFG, r);
+
+	asm volatile ("sync; isync" ::: "memory");
+	local_irq_restore(flags);
+
+	printk(KERN_INFO "%dk L2-cache enabled\n", l2_size >> 10);
+
+	of_node_put(np);
+	return 0;
+}
+arch_initcall(ppc4xx_l2c_probe);