/*
* 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;
unsigned long phys;
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;
static unsigned long cci_ctrl_phys;
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_enable_port_for_self() - enable a CCI port for calling CPU
*
* Enabling a CCI port for the calling CPU implies enabling the CCI
* port controlling that CPU's cluster. Caller must make sure that the
* CPU running the code is the first active CPU in the cluster and all
* other CPUs are quiescent in a low power state or waiting for this CPU
* to complete the CCI initialization.
*
* Because this is called when the MMU is still off and with no stack,
* the code must be position independent and ideally rely on callee
* clobbered registers only. To achieve this we must code this function
* entirely in assembler.
*
* On success this returns with the proper CCI port enabled. In case of
* any failure this never returns as the inability to enable the CCI is
* fatal and there is no possible recovery at this stage.
*/
asmlinkage void __naked cci_enable_port_for_self(void)
{
asm volatile ("\n"
" .arch armv7-a\n"
" mrc p15, 0, r0, c0, c0, 5 @ get MPIDR value \n"
" and r0, r0, #"__stringify(MPIDR_HWID_BITMASK)" \n"
" adr r1, 5f \n"
" ldr r2, [r1] \n"
" add r1, r1, r2 @ &cpu_port \n"
" add ip, r1, %[sizeof_cpu_port] \n"
/* Loop over the cpu_port array looking for a matching MPIDR */
"1: ldr r2, [r1, %[offsetof_cpu_port_mpidr_lsb]] \n"
" cmp r2, r0 @ compare MPIDR \n"
" bne 2f \n"
/* Found a match, now test port validity */
" ldr r3, [r1, %[offsetof_cpu_port_port]] \n"
" tst r3, #"__stringify(PORT_VALID)" \n"
" bne 3f \n"
/* no match, loop with the next cpu_port entry */
"2: add r1, r1, %[sizeof_struct_cpu_port] \n"
" cmp r1, ip @ done? \n"
" blo 1b \n"
/* CCI port not found -- cheaply try to stall this CPU */
"cci_port_not_found: \n"
" wfi \n"
" wfe \n"
" b cci_port_not_found \n"
/* Use matched port index to look up the corresponding ports entry */
"3: bic r3, r3, #"__stringify(PORT_VALID)" \n"
" adr r0, 6f \n"
" ldmia r0, {r1, r2} \n"
" sub r1, r1, r0 @ virt - phys \n"
" ldr r0, [r0, r2] @ *(&ports) \n"
" mov r2, %[sizeof_struct_ace_port] \n"
" mla r0, r2, r3, r0 @ &ports[index] \n"
" sub r0, r0, r1 @ virt_to_phys() \n"
/* Enable the CCI port */
" ldr r0, [r0, %[offsetof_port_phys]] \n"
" mov r3, #"__stringify(CCI_ENABLE_REQ)" \n"
" str r3, [r0, #"__stringify(CCI_PORT_CTRL)"] \n"
/* poll the status reg for completion */
" adr r1, 7f \n"
" ldr r0, [r1] \n"
" ldr r0, [r0, r1] @ cci_ctrl_base \n"
"4: ldr r1, [r0, #"__stringify(CCI_CTRL_STATUS)"] \n"
" tst r1, #1 \n"
" bne 4b \n"
" mov r0, #0 \n"
" bx lr \n"
" .align 2 \n"
"5: .word cpu_port - . \n"
"6: .word . \n"
" .word ports - 6b \n"
"7: .word cci_ctrl_phys - . \n"
: :
[sizeof_cpu_port] "i" (sizeof(cpu_port)),
#ifndef __ARMEB__
[offsetof_cpu_port_mpidr_lsb] "i" (offsetof(struct cpu_port, mpidr)),
#else
[offsetof_cpu_port_mpidr_lsb] "i" (offsetof(struct cpu_port, mpidr)+4),
#endif
[offsetof_cpu_port_port] "i" (offsetof(struct cpu_port, port)),
[sizeof_struct_cpu_port] "i" (sizeof(struct cpu_port)),
[sizeof_struct_ace_port] "i" (sizeof(struct cci_ace_port)),
[offsetof_port_phys] "i" (offsetof(struct cci_ace_port, phys)) );
unreachable();
}
/**
* __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;
struct resource res;
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;
ret = of_address_to_resource(np, 0, &res);
if (!ret) {
cci_ctrl_base = ioremap(res.start, resource_size(&res));
cci_ctrl_phys = res.start;
}
if (ret || !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;
}
ret = of_address_to_resource(cp, 0, &res);
if (!ret) {
ports[i].base = ioremap(res.start, resource_size(&res));
ports[i].phys = res.start;
}
if (ret || !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(&cci_ctrl_phys);
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");
