diff options
Diffstat (limited to 'drivers/bus/arm-cci.c')
| -rw-r--r-- | drivers/bus/arm-cci.c | 426 |
1 files changed, 426 insertions, 0 deletions
diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c new file mode 100644 index 000000000000..ea81fa4a28db --- /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"); |