Initial import

1 files changed, 174 insertions, 0 deletions

diff --git a/arch/arm/mach-vexpress/dcscb.c b/arch/arm/mach-vexpress/dcscb.c
new file mode 100644
index 000000000..5cedcf572
--- /dev/null
+++ b/arch/arm/mach-vexpress/dcscb.c
@@ -0,0 +1,174 @@
+/*
+ * arch/arm/mach-vexpress/dcscb.c - Dual Cluster System Configuration Block
+ *
+ * Created by:	Nicolas Pitre, May 2012
+ * Copyright:	(C) 2012-2013  Linaro Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/errno.h>
+#include <linux/of_address.h>
+#include <linux/vexpress.h>
+#include <linux/arm-cci.h>
+
+#include <asm/mcpm.h>
+#include <asm/proc-fns.h>
+#include <asm/cacheflush.h>
+#include <asm/cputype.h>
+#include <asm/cp15.h>
+
+
+#define RST_HOLD0	0x0
+#define RST_HOLD1	0x4
+#define SYS_SWRESET	0x8
+#define RST_STAT0	0xc
+#define RST_STAT1	0x10
+#define EAG_CFG_R	0x20
+#define EAG_CFG_W	0x24
+#define KFC_CFG_R	0x28
+#define KFC_CFG_W	0x2c
+#define DCS_CFG_R	0x30
+
+static void __iomem *dcscb_base;
+static int dcscb_allcpus_mask[2];
+
+static int dcscb_cpu_powerup(unsigned int cpu, unsigned int cluster)
+{
+	unsigned int rst_hold, cpumask = (1 << cpu);
+
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	if (cluster >= 2 || !(cpumask & dcscb_allcpus_mask[cluster]))
+		return -EINVAL;
+
+	rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
+	rst_hold &= ~(cpumask | (cpumask << 4));
+	writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
+	return 0;
+}
+
+static int dcscb_cluster_powerup(unsigned int cluster)
+{
+	unsigned int rst_hold;
+
+	pr_debug("%s: cluster %u\n", __func__, cluster);
+	if (cluster >= 2)
+		return -EINVAL;
+
+	/* remove cluster reset and add individual CPU's reset */
+	rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
+	rst_hold &= ~(1 << 8);
+	rst_hold |= dcscb_allcpus_mask[cluster];
+	writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
+	return 0;
+}
+
+static void dcscb_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster)
+{
+	unsigned int rst_hold;
+
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	BUG_ON(cluster >= 2 || !((1 << cpu) & dcscb_allcpus_mask[cluster]));
+
+	rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
+	rst_hold |= (1 << cpu);
+	writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
+}
+
+static void dcscb_cluster_powerdown_prepare(unsigned int cluster)
+{
+	unsigned int rst_hold;
+
+	pr_debug("%s: cluster %u\n", __func__, cluster);
+	BUG_ON(cluster >= 2);
+
+	rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
+	rst_hold |= (1 << 8);
+	writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
+}
+
+static void dcscb_cpu_cache_disable(void)
+{
+	/* Disable and flush the local CPU cache. */
+	v7_exit_coherency_flush(louis);
+}
+
+static void dcscb_cluster_cache_disable(void)
+{
+	/* Flush all cache levels for this cluster. */
+	v7_exit_coherency_flush(all);
+
+	/*
+	 * A full outer cache flush could be needed at this point
+	 * on platforms with such a cache, depending on where the
+	 * outer cache sits. In some cases the notion of a "last
+	 * cluster standing" would need to be implemented if the
+	 * outer cache is shared across clusters. In any case, when
+	 * the outer cache needs flushing, there is no concurrent
+	 * access to the cache controller to worry about and no
+	 * special locking besides what is already provided by the
+	 * MCPM state machinery is needed.
+	 */
+
+	/*
+	 * Disable cluster-level coherency by masking
+	 * incoming snoops and DVM messages:
+	 */
+	cci_disable_port_by_cpu(read_cpuid_mpidr());
+}
+
+static const struct mcpm_platform_ops dcscb_power_ops = {
+	.cpu_powerup		= dcscb_cpu_powerup,
+	.cluster_powerup	= dcscb_cluster_powerup,
+	.cpu_powerdown_prepare	= dcscb_cpu_powerdown_prepare,
+	.cluster_powerdown_prepare = dcscb_cluster_powerdown_prepare,
+	.cpu_cache_disable	= dcscb_cpu_cache_disable,
+	.cluster_cache_disable	= dcscb_cluster_cache_disable,
+};
+
+extern void dcscb_power_up_setup(unsigned int affinity_level);
+
+static int __init dcscb_init(void)
+{
+	struct device_node *node;
+	unsigned int cfg;
+	int ret;
+
+	if (!cci_probed())
+		return -ENODEV;
+
+	node = of_find_compatible_node(NULL, NULL, "arm,rtsm,dcscb");
+	if (!node)
+		return -ENODEV;
+	dcscb_base = of_iomap(node, 0);
+	if (!dcscb_base)
+		return -EADDRNOTAVAIL;
+	cfg = readl_relaxed(dcscb_base + DCS_CFG_R);
+	dcscb_allcpus_mask[0] = (1 << (((cfg >> 16) >> (0 << 2)) & 0xf)) - 1;
+	dcscb_allcpus_mask[1] = (1 << (((cfg >> 16) >> (1 << 2)) & 0xf)) - 1;
+
+	ret = mcpm_platform_register(&dcscb_power_ops);
+	if (!ret)
+		ret = mcpm_sync_init(dcscb_power_up_setup);
+	if (ret) {
+		iounmap(dcscb_base);
+		return ret;
+	}
+
+	pr_info("VExpress DCSCB support installed\n");
+
+	/*
+	 * Future entries into the kernel can now go
+	 * through the cluster entry vectors.
+	 */
+	vexpress_flags_set(virt_to_phys(mcpm_entry_point));
+
+	return 0;
+}
+
+early_initcall(dcscb_init);