[PATCH 1/2 v2] [POWERPC] Add PPC4xx L2-cache support (440GX)
Josh Boyer
jwboyer at linux.vnet.ibm.com
Tue Mar 25 00:39:57 EST 2008
On Sat, 22 Mar 2008 11:28:56 +0100
Stefan Roese <sr at denx.de> wrote:
> 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 at denx.de>
Hi Stefan. Small, very minor issues below.
> diff --git a/arch/powerpc/sysdev/ppc4xx_soc.c b/arch/powerpc/sysdev/ppc4xx_soc.c
> new file mode 100644
> index 0000000..4847555
> --- /dev/null
> +++ b/arch/powerpc/sysdev/ppc4xx_soc.c
> @@ -0,0 +1,178 @@
> +/*
> + * IBM/AMCC PPC4xx SoC setup code
> + *
> + * Copyright 2008 DENX Software Engineering, Stefan Roese <sr at denx.de>
> + *
> + * L2 cache routines cloned from arch/ppc/syslib/ibm440gx_common.c which is:
> + * Eugene Surovegin <eugene.surovegin at zultys.com> or <ebs at 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;
If this file is really intended to have other miscellaneous stuff added
to it, perhaps this variable should be renamed l2_dcrbase. I know it's
minor, so perhaps we can wait until something else gets added.
> +
> +/*
> + * L2-cache
> + */
> +
> +/* Issue L2C diagnostic command */
> +static inline u32 l2c_diag(u32 addr)
> +{
> + mtdcr(dcrbase + DCRN_L2C0_ADDR, addr);
> + mtdcr(dcrbase + DCRN_L2C0_CMD, L2C_CMD_DIAG);
> + while (!(mfdcr(dcrbase + DCRN_L2C0_SR) & L2C_SR_CC))
> + ;
> +
> + return mfdcr(dcrbase + DCRN_L2C0_DATA);
> +}
> +
> +static irqreturn_t l2c_error_handler(int irq, void *dev)
> +{
> + u32 sr = mfdcr(dcrbase + DCRN_L2C0_SR);
> +
> + if (sr & L2C_SR_CPE) {
> + /* Read cache trapped address */
> + u32 addr = l2c_diag(0x42000000);
What is this magical hex number?
> + 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;
And here?
> + 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 + DCRN_L2C0_ADDR, 0);
> + mtdcr(dcrbase + 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;
> +
> + np = of_find_compatible_node(np, NULL, "ibm,l2-cache");
> + if (!np)
> + return 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 = 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");
Perhaps just call iosync() for these instead of the open coded asm
volatile stuff?
> +
> + /* 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 + DCRN_L2C0_CFG) &
> + ~(L2C_CFG_ICU | L2C_CFG_DCU | L2C_CFG_SS_MASK);
> + r |= L2C_CFG_L2M | L2C_CFG_SS_256;
> + mtdcr(dcrbase + DCRN_L2C0_CFG, r);
> +
> + mtdcr(dcrbase + DCRN_L2C0_ADDR, 0);
> +
> + /* Hardware Clear Command */
> + mtdcr(dcrbase + DCRN_L2C0_CMD, L2C_CMD_HCC);
> + while (!(mfdcr(dcrbase + DCRN_L2C0_SR) & L2C_SR_CC))
> + ;
> +
> + /* Clear Cache Parity and Tag Errors */
> + mtdcr(dcrbase + DCRN_L2C0_CMD, L2C_CMD_CCP | L2C_CMD_CTE);
> +
> + /* Enable 64G snoop region starting at 0 */
> + r = mfdcr(dcrbase + DCRN_L2C0_SNP0) &
> + ~(L2C_SNP_BA_MASK | L2C_SNP_SSR_MASK);
> + r |= L2C_SNP_SSR_32G | L2C_SNP_ESR;
> + mtdcr(dcrbase + DCRN_L2C0_SNP0, r);
> +
> + r = mfdcr(dcrbase + DCRN_L2C0_SNP1) &
> + ~(L2C_SNP_BA_MASK | L2C_SNP_SSR_MASK);
> + r |= 0x80000000 | L2C_SNP_SSR_32G | L2C_SNP_ESR;
> + mtdcr(dcrbase + DCRN_L2C0_SNP1, r);
> +
> + asm volatile ("sync" ::: "memory");
> +
> + /* Enable ICU/DCU ports */
> + r = mfdcr(dcrbase + 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 + DCRN_L2C0_CFG, r);
> +
> + asm volatile ("sync; isync" ::: "memory");
> + local_irq_restore(flags);
> +
> + printk(KERN_INFO "256k L2-cache enabled\n");
Should the cache size be derived from the device tree?
josh
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