diff options
Diffstat (limited to 'drivers/mfd/vexpress-config.c')
| -rw-r--r-- | drivers/mfd/vexpress-config.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/drivers/mfd/vexpress-config.c b/drivers/mfd/vexpress-config.c new file mode 100644 index 000000000000..fae15d880758 --- /dev/null +++ b/drivers/mfd/vexpress-config.c @@ -0,0 +1,277 @@ +/* + * 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 in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Copyright (C) 2012 ARM Limited + */ + +#define pr_fmt(fmt) "vexpress-config: " fmt + +#include <linux/bitops.h> +#include <linux/completion.h> +#include <linux/export.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/vexpress.h> + + +#define VEXPRESS_CONFIG_MAX_BRIDGES 2 + +struct vexpress_config_bridge { + struct device_node *node; + struct vexpress_config_bridge_info *info; + struct list_head transactions; + spinlock_t transactions_lock; +} vexpress_config_bridges[VEXPRESS_CONFIG_MAX_BRIDGES]; + +static DECLARE_BITMAP(vexpress_config_bridges_map, + ARRAY_SIZE(vexpress_config_bridges)); +static DEFINE_MUTEX(vexpress_config_bridges_mutex); + +struct vexpress_config_bridge *vexpress_config_bridge_register( + struct device_node *node, + struct vexpress_config_bridge_info *info) +{ + struct vexpress_config_bridge *bridge; + int i; + + pr_debug("Registering bridge '%s'\n", info->name); + + mutex_lock(&vexpress_config_bridges_mutex); + i = find_first_zero_bit(vexpress_config_bridges_map, + ARRAY_SIZE(vexpress_config_bridges)); + if (i >= ARRAY_SIZE(vexpress_config_bridges)) { + pr_err("Can't register more bridges!\n"); + mutex_unlock(&vexpress_config_bridges_mutex); + return NULL; + } + __set_bit(i, vexpress_config_bridges_map); + bridge = &vexpress_config_bridges[i]; + + bridge->node = node; + bridge->info = info; + INIT_LIST_HEAD(&bridge->transactions); + spin_lock_init(&bridge->transactions_lock); + + mutex_unlock(&vexpress_config_bridges_mutex); + + return bridge; +} + +void vexpress_config_bridge_unregister(struct vexpress_config_bridge *bridge) +{ + struct vexpress_config_bridge __bridge = *bridge; + int i; + + mutex_lock(&vexpress_config_bridges_mutex); + for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++) + if (&vexpress_config_bridges[i] == bridge) + __clear_bit(i, vexpress_config_bridges_map); + mutex_unlock(&vexpress_config_bridges_mutex); + + WARN_ON(!list_empty(&__bridge.transactions)); + while (!list_empty(&__bridge.transactions)) + cpu_relax(); +} + + +struct vexpress_config_func { + struct vexpress_config_bridge *bridge; + void *func; +}; + +struct vexpress_config_func *__vexpress_config_func_get(struct device *dev, + struct device_node *node) +{ + struct device_node *bridge_node; + struct vexpress_config_func *func; + int i; + + if (WARN_ON(dev && node && dev->of_node != node)) + return NULL; + if (dev && !node) + node = dev->of_node; + + func = kzalloc(sizeof(*func), GFP_KERNEL); + if (!func) + return NULL; + + bridge_node = of_node_get(node); + while (bridge_node) { + const __be32 *prop = of_get_property(bridge_node, + "arm,vexpress,config-bridge", NULL); + + if (prop) { + bridge_node = of_find_node_by_phandle( + be32_to_cpup(prop)); + break; + } + + bridge_node = of_get_next_parent(bridge_node); + } + + mutex_lock(&vexpress_config_bridges_mutex); + for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++) { + struct vexpress_config_bridge *bridge = + &vexpress_config_bridges[i]; + + if (test_bit(i, vexpress_config_bridges_map) && + bridge->node == bridge_node) { + func->bridge = bridge; + func->func = bridge->info->func_get(dev, node); + break; + } + } + mutex_unlock(&vexpress_config_bridges_mutex); + + if (!func->func) { + of_node_put(node); + kfree(func); + return NULL; + } + + return func; +} + +void vexpress_config_func_put(struct vexpress_config_func *func) +{ + func->bridge->info->func_put(func->func); + of_node_put(func->bridge->node); + kfree(func); +} + + +struct vexpress_config_trans { + struct vexpress_config_func *func; + int offset; + bool write; + u32 *data; + int status; + struct completion completion; + struct list_head list; +}; + +static void vexpress_config_dump_trans(const char *what, + struct vexpress_config_trans *trans) +{ + pr_debug("%s %s trans %p func 0x%p offset %d data 0x%x status %d\n", + what, trans->write ? "write" : "read", trans, + trans->func->func, trans->offset, + trans->data ? *trans->data : 0, trans->status); +} + +static int vexpress_config_schedule(struct vexpress_config_trans *trans) +{ + int status; + struct vexpress_config_bridge *bridge = trans->func->bridge; + unsigned long flags; + + init_completion(&trans->completion); + trans->status = -EFAULT; + + spin_lock_irqsave(&bridge->transactions_lock, flags); + + vexpress_config_dump_trans("Executing", trans); + + if (list_empty(&bridge->transactions)) + status = bridge->info->func_exec(trans->func->func, + trans->offset, trans->write, trans->data); + else + status = VEXPRESS_CONFIG_STATUS_WAIT; + + switch (status) { + case VEXPRESS_CONFIG_STATUS_DONE: + vexpress_config_dump_trans("Finished", trans); + trans->status = status; + break; + case VEXPRESS_CONFIG_STATUS_WAIT: + list_add_tail(&trans->list, &bridge->transactions); + break; + } + + spin_unlock_irqrestore(&bridge->transactions_lock, flags); + + return status; +} + +void vexpress_config_complete(struct vexpress_config_bridge *bridge, + int status) +{ + struct vexpress_config_trans *trans; + unsigned long flags; + + spin_lock_irqsave(&bridge->transactions_lock, flags); + + trans = list_first_entry(&bridge->transactions, + struct vexpress_config_trans, list); + vexpress_config_dump_trans("Completed", trans); + + trans->status = status; + list_del(&trans->list); + + if (!list_empty(&bridge->transactions)) { + vexpress_config_dump_trans("Pending", trans); + + bridge->info->func_exec(trans->func->func, trans->offset, + trans->write, trans->data); + } + spin_unlock_irqrestore(&bridge->transactions_lock, flags); + + complete(&trans->completion); +} + +int vexpress_config_wait(struct vexpress_config_trans *trans) +{ + wait_for_completion(&trans->completion); + + return trans->status; +} + + +int vexpress_config_read(struct vexpress_config_func *func, int offset, + u32 *data) +{ + struct vexpress_config_trans trans = { + .func = func, + .offset = offset, + .write = false, + .data = data, + .status = 0, + }; + int status = vexpress_config_schedule(&trans); + + if (status == VEXPRESS_CONFIG_STATUS_WAIT) + status = vexpress_config_wait(&trans); + + return status; +} +EXPORT_SYMBOL(vexpress_config_read); + +int vexpress_config_write(struct vexpress_config_func *func, int offset, + u32 data) +{ + struct vexpress_config_trans trans = { + .func = func, + .offset = offset, + .write = true, + .data = &data, + .status = 0, + }; + int status = vexpress_config_schedule(&trans); + + if (status == VEXPRESS_CONFIG_STATUS_WAIT) + status = vexpress_config_wait(&trans); + + return status; +} +EXPORT_SYMBOL(vexpress_config_write); |