summaryrefslogtreecommitdiffstats
path: root/drivers/bus
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/bus')
-rw-r--r--drivers/bus/Kconfig7
-rw-r--r--drivers/bus/Makefile2
-rw-r--r--drivers/bus/arm-cci.c426
3 files changed, 435 insertions, 0 deletions
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index b05ecab..5286e2d 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -26,4 +26,11 @@ config OMAP_INTERCONNECT
help
Driver to enable OMAP interconnect error handling driver.
+
+config ARM_CCI
+ bool "ARM CCI driver support"
+ depends on ARM
+ help
+ Driver supporting the CCI cache coherent interconnect for ARM
+ platforms.
endmenu
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index 3c7b53c..670cea4 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -7,3 +7,5 @@ obj-$(CONFIG_OMAP_OCP2SCP) += omap-ocp2scp.o
# Interconnect bus driver for OMAP SoCs.
obj-$(CONFIG_OMAP_INTERCONNECT) += omap_l3_smx.o omap_l3_noc.o
+# CCI cache coherent interconnect for ARM platforms
+obj-$(CONFIG_ARM_CCI) += arm-cci.o
diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
new file mode 100644
index 0000000..ea81fa4
--- /dev/null
+++ b/drivers/bus/arm-cci.c
@@ -0,0 +1,426 @@
+/*
+ * CCI cache coherent interconnect driver
+ *
+ * Copyright (C) 2013 ARM Ltd.
+ * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
+ *
+ * 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.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/arm-cci.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+
+#include <asm/cacheflush.h>
+#include <asm/smp_plat.h>
+
+#define CCI_PORT_CTRL 0x0
+#define CCI_CTRL_STATUS 0xc
+
+#define CCI_ENABLE_SNOOP_REQ 0x1
+#define CCI_ENABLE_DVM_REQ 0x2
+#define CCI_ENABLE_REQ (CCI_ENABLE_SNOOP_REQ | CCI_ENABLE_DVM_REQ)
+
+struct cci_nb_ports {
+ unsigned int nb_ace;
+ unsigned int nb_ace_lite;
+};
+
+enum cci_ace_port_type {
+ ACE_INVALID_PORT = 0x0,
+ ACE_PORT,
+ ACE_LITE_PORT,
+};
+
+struct cci_ace_port {
+ void __iomem *base;
+ enum cci_ace_port_type type;
+ struct device_node *dn;
+};
+
+static struct cci_ace_port *ports;
+static unsigned int nb_cci_ports;
+
+static void __iomem *cci_ctrl_base;
+
+struct cpu_port {
+ u64 mpidr;
+ u32 port;
+};
+/*
+ * Use the port MSB as valid flag, shift can be made dynamic
+ * by computing number of bits required for port indexes.
+ * Code disabling CCI cpu ports runs with D-cache invalidated
+ * and SCTLR bit clear so data accesses must be kept to a minimum
+ * to improve performance; for now shift is left static to
+ * avoid one more data access while disabling the CCI port.
+ */
+#define PORT_VALID_SHIFT 31
+#define PORT_VALID (0x1 << PORT_VALID_SHIFT)
+
+static inline void init_cpu_port(struct cpu_port *port, u32 index, u64 mpidr)
+{
+ port->port = PORT_VALID | index;
+ port->mpidr = mpidr;
+}
+
+static inline bool cpu_port_is_valid(struct cpu_port *port)
+{
+ return !!(port->port & PORT_VALID);
+}
+
+static inline bool cpu_port_match(struct cpu_port *port, u64 mpidr)
+{
+ return port->mpidr == (mpidr & MPIDR_HWID_BITMASK);
+}
+
+static struct cpu_port cpu_port[NR_CPUS];
+
+/**
+ * __cci_ace_get_port - Function to retrieve the port index connected to
+ * a cpu or device.
+ *
+ * @dn: device node of the device to look-up
+ * @type: port type
+ *
+ * Return value:
+ * - CCI port index if success
+ * - -ENODEV if failure
+ */
+static int __cci_ace_get_port(struct device_node *dn, int type)
+{
+ int i;
+ bool ace_match;
+ struct device_node *cci_portn;
+
+ cci_portn = of_parse_phandle(dn, "cci-control-port", 0);
+ for (i = 0; i < nb_cci_ports; i++) {
+ ace_match = ports[i].type == type;
+ if (ace_match && cci_portn == ports[i].dn)
+ return i;
+ }
+ return -ENODEV;
+}
+
+int cci_ace_get_port(struct device_node *dn)
+{
+ return __cci_ace_get_port(dn, ACE_LITE_PORT);
+}
+EXPORT_SYMBOL_GPL(cci_ace_get_port);
+
+static void __init cci_ace_init_ports(void)
+{
+ int port, ac, cpu;
+ u64 hwid;
+ const u32 *cell;
+ struct device_node *cpun, *cpus;
+
+ cpus = of_find_node_by_path("/cpus");
+ if (WARN(!cpus, "Missing cpus node, bailing out\n"))
+ return;
+
+ if (WARN_ON(of_property_read_u32(cpus, "#address-cells", &ac)))
+ ac = of_n_addr_cells(cpus);
+
+ /*
+ * Port index look-up speeds up the function disabling ports by CPU,
+ * since the logical to port index mapping is done once and does
+ * not change after system boot.
+ * The stashed index array is initialized for all possible CPUs
+ * at probe time.
+ */
+ for_each_child_of_node(cpus, cpun) {
+ if (of_node_cmp(cpun->type, "cpu"))
+ continue;
+ cell = of_get_property(cpun, "reg", NULL);
+ if (WARN(!cell, "%s: missing reg property\n", cpun->full_name))
+ continue;
+
+ hwid = of_read_number(cell, ac);
+ cpu = get_logical_index(hwid & MPIDR_HWID_BITMASK);
+
+ if (cpu < 0 || !cpu_possible(cpu))
+ continue;
+ port = __cci_ace_get_port(cpun, ACE_PORT);
+ if (port < 0)
+ continue;
+
+ init_cpu_port(&cpu_port[cpu], port, cpu_logical_map(cpu));
+ }
+
+ for_each_possible_cpu(cpu) {
+ WARN(!cpu_port_is_valid(&cpu_port[cpu]),
+ "CPU %u does not have an associated CCI port\n",
+ cpu);
+ }
+}
+/*
+ * Functions to enable/disable a CCI interconnect slave port
+ *
+ * They are called by low-level power management code to disable slave
+ * interfaces snoops and DVM broadcast.
+ * Since they may execute with cache data allocation disabled and
+ * after the caches have been cleaned and invalidated the functions provide
+ * no explicit locking since they may run with D-cache disabled, so normal
+ * cacheable kernel locks based on ldrex/strex may not work.
+ * Locking has to be provided by BSP implementations to ensure proper
+ * operations.
+ */
+
+/**
+ * cci_port_control() - function to control a CCI port
+ *
+ * @port: index of the port to setup
+ * @enable: if true enables the port, if false disables it
+ */
+static void notrace cci_port_control(unsigned int port, bool enable)
+{
+ void __iomem *base = ports[port].base;
+
+ writel_relaxed(enable ? CCI_ENABLE_REQ : 0, base + CCI_PORT_CTRL);
+ /*
+ * This function is called from power down procedures
+ * and must not execute any instruction that might
+ * cause the processor to be put in a quiescent state
+ * (eg wfi). Hence, cpu_relax() can not be added to this
+ * read loop to optimize power, since it might hide possibly
+ * disruptive operations.
+ */
+ while (readl_relaxed(cci_ctrl_base + CCI_CTRL_STATUS) & 0x1)
+ ;
+}
+
+/**
+ * cci_disable_port_by_cpu() - function to disable a CCI port by CPU
+ * reference
+ *
+ * @mpidr: mpidr of the CPU whose CCI port should be disabled
+ *
+ * Disabling a CCI port for a CPU implies disabling the CCI port
+ * controlling that CPU cluster. Code disabling CPU CCI ports
+ * must make sure that the CPU running the code is the last active CPU
+ * in the cluster ie all other CPUs are quiescent in a low power state.
+ *
+ * Return:
+ * 0 on success
+ * -ENODEV on port look-up failure
+ */
+int notrace cci_disable_port_by_cpu(u64 mpidr)
+{
+ int cpu;
+ bool is_valid;
+ for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
+ is_valid = cpu_port_is_valid(&cpu_port[cpu]);
+ if (is_valid && cpu_port_match(&cpu_port[cpu], mpidr)) {
+ cci_port_control(cpu_port[cpu].port, false);
+ return 0;
+ }
+ }
+ return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(cci_disable_port_by_cpu);
+
+/**
+ * __cci_control_port_by_device() - function to control a CCI port by device
+ * reference
+ *
+ * @dn: device node pointer of the device whose CCI port should be
+ * controlled
+ * @enable: if true enables the port, if false disables it
+ *
+ * Return:
+ * 0 on success
+ * -ENODEV on port look-up failure
+ */
+int notrace __cci_control_port_by_device(struct device_node *dn, bool enable)
+{
+ int port;
+
+ if (!dn)
+ return -ENODEV;
+
+ port = __cci_ace_get_port(dn, ACE_LITE_PORT);
+ if (WARN_ONCE(port < 0, "node %s ACE lite port look-up failure\n",
+ dn->full_name))
+ return -ENODEV;
+ cci_port_control(port, enable);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__cci_control_port_by_device);
+
+/**
+ * __cci_control_port_by_index() - function to control a CCI port by port index
+ *
+ * @port: port index previously retrieved with cci_ace_get_port()
+ * @enable: if true enables the port, if false disables it
+ *
+ * Return:
+ * 0 on success
+ * -ENODEV on port index out of range
+ * -EPERM if operation carried out on an ACE PORT
+ */
+int notrace __cci_control_port_by_index(u32 port, bool enable)
+{
+ if (port >= nb_cci_ports || ports[port].type == ACE_INVALID_PORT)
+ return -ENODEV;
+ /*
+ * CCI control for ports connected to CPUS is extremely fragile
+ * and must be made to go through a specific and controlled
+ * interface (ie cci_disable_port_by_cpu(); control by general purpose
+ * indexing is therefore disabled for ACE ports.
+ */
+ if (ports[port].type == ACE_PORT)
+ return -EPERM;
+
+ cci_port_control(port, enable);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__cci_control_port_by_index);
+
+static const struct cci_nb_ports cci400_ports = {
+ .nb_ace = 2,
+ .nb_ace_lite = 3
+};
+
+static const struct of_device_id arm_cci_matches[] = {
+ {.compatible = "arm,cci-400", .data = &cci400_ports },
+ {},
+};
+
+static const struct of_device_id arm_cci_ctrl_if_matches[] = {
+ {.compatible = "arm,cci-400-ctrl-if", },
+ {},
+};
+
+static int __init cci_probe(void)
+{
+ struct cci_nb_ports const *cci_config;
+ int ret, i, nb_ace = 0, nb_ace_lite = 0;
+ struct device_node *np, *cp;
+ const char *match_str;
+ bool is_ace;
+
+ np = of_find_matching_node(NULL, arm_cci_matches);
+ if (!np)
+ return -ENODEV;
+
+ cci_config = of_match_node(arm_cci_matches, np)->data;
+ if (!cci_config)
+ return -ENODEV;
+
+ nb_cci_ports = cci_config->nb_ace + cci_config->nb_ace_lite;
+
+ ports = kcalloc(sizeof(*ports), nb_cci_ports, GFP_KERNEL);
+ if (!ports)
+ return -ENOMEM;
+
+ cci_ctrl_base = of_iomap(np, 0);
+
+ if (!cci_ctrl_base) {
+ WARN(1, "unable to ioremap CCI ctrl\n");
+ ret = -ENXIO;
+ goto memalloc_err;
+ }
+
+ for_each_child_of_node(np, cp) {
+ if (!of_match_node(arm_cci_ctrl_if_matches, cp))
+ continue;
+
+ i = nb_ace + nb_ace_lite;
+
+ if (i >= nb_cci_ports)
+ break;
+
+ if (of_property_read_string(cp, "interface-type",
+ &match_str)) {
+ WARN(1, "node %s missing interface-type property\n",
+ cp->full_name);
+ continue;
+ }
+ is_ace = strcmp(match_str, "ace") == 0;
+ if (!is_ace && strcmp(match_str, "ace-lite")) {
+ WARN(1, "node %s containing invalid interface-type property, skipping it\n",
+ cp->full_name);
+ continue;
+ }
+
+ ports[i].base = of_iomap(cp, 0);
+
+ if (!ports[i].base) {
+ WARN(1, "unable to ioremap CCI port %d\n", i);
+ continue;
+ }
+
+ if (is_ace) {
+ if (WARN_ON(nb_ace >= cci_config->nb_ace))
+ continue;
+ ports[i].type = ACE_PORT;
+ ++nb_ace;
+ } else {
+ if (WARN_ON(nb_ace_lite >= cci_config->nb_ace_lite))
+ continue;
+ ports[i].type = ACE_LITE_PORT;
+ ++nb_ace_lite;
+ }
+ ports[i].dn = cp;
+ }
+
+ /* initialize a stashed array of ACE ports to speed-up look-up */
+ cci_ace_init_ports();
+
+ /*
+ * Multi-cluster systems may need this data when non-coherent, during
+ * cluster power-up/power-down. Make sure it reaches main memory.
+ */
+ sync_cache_w(&cci_ctrl_base);
+ sync_cache_w(&ports);
+ sync_cache_w(&cpu_port);
+ __sync_cache_range_w(ports, sizeof(*ports) * nb_cci_ports);
+ pr_info("ARM CCI driver probed\n");
+ return 0;
+
+memalloc_err:
+
+ kfree(ports);
+ return ret;
+}
+
+static int cci_init_status = -EAGAIN;
+static DEFINE_MUTEX(cci_probing);
+
+static int __init cci_init(void)
+{
+ if (cci_init_status != -EAGAIN)
+ return cci_init_status;
+
+ mutex_lock(&cci_probing);
+ if (cci_init_status == -EAGAIN)
+ cci_init_status = cci_probe();
+ mutex_unlock(&cci_probing);
+ return cci_init_status;
+}
+
+/*
+ * To sort out early init calls ordering a helper function is provided to
+ * check if the CCI driver has beed initialized. Function check if the driver
+ * has been initialized, if not it calls the init function that probes
+ * the driver and updates the return value.
+ */
+bool __init cci_probed(void)
+{
+ return cci_init() == 0;
+}
+EXPORT_SYMBOL_GPL(cci_probed);
+
+early_initcall(cci_init);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ARM CCI support");
OpenPOWER on IntegriCloud