From 3d26c20bae9e97c98f7240184427d3a38515d406 Mon Sep 17 00:00:00 2001 From: Andres Salomon Date: Wed, 11 Jul 2012 17:40:25 -0700 Subject: [PATCH] Platform: OLPC: allow EC cmd to be overridden, and create a workqueue to call it This provides a new API allows different OLPC architectures to override the EC driver. x86 and ARM OLPC machines use completely different EC backends. The olpc_ec_cmd is synchronous, and waits for the workqueue to send the command to the EC. Multiple callers can run olpc_ec_cmd() at once, and they will by serialized and sleep while only one executes on the EC at a time. We don't provide an unregister function, as that doesn't make sense within the context of OLPC machines - there's only ever 1 EC, it's critical to functionality, and it certainly not hotpluggable. Signed-off-by: Andres Salomon Acked-by: Paul Fox Reviewed-by: Thomas Gleixner --- drivers/platform/olpc/olpc-ec.c | 112 +++++++++++++++++++++++++++++++- include/linux/olpc-ec.h | 6 ++ 2 files changed, 116 insertions(+), 2 deletions(-) diff --git a/drivers/platform/olpc/olpc-ec.c b/drivers/platform/olpc/olpc-ec.c index 42026036cd3e..44e6a4fae79b 100644 --- a/drivers/platform/olpc/olpc-ec.c +++ b/drivers/platform/olpc/olpc-ec.c @@ -5,12 +5,120 @@ * * Licensed under the GPL v2 or later. */ +#include +#include +#include +#include #include +#include +#include #include +struct ec_cmd_desc { + u8 cmd; + u8 *inbuf, *outbuf; + size_t inlen, outlen; + + int err; + struct completion finished; + struct list_head node; + + void *priv; +}; + +static void olpc_ec_worker(struct work_struct *w); + +static DECLARE_WORK(ec_worker, olpc_ec_worker); +static LIST_HEAD(ec_cmd_q); +static DEFINE_SPINLOCK(ec_cmd_q_lock); + +static struct olpc_ec_driver *ec_driver; +static void *ec_cb_arg; +static DEFINE_MUTEX(ec_cb_lock); + +void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg) +{ + ec_driver = drv; + ec_cb_arg = arg; +} +EXPORT_SYMBOL_GPL(olpc_ec_driver_register); + +static void olpc_ec_worker(struct work_struct *w) +{ + struct ec_cmd_desc *desc = NULL; + unsigned long flags; + + /* Grab the first pending command from the queue */ + spin_lock_irqsave(&ec_cmd_q_lock, flags); + if (!list_empty(&ec_cmd_q)) { + desc = list_first_entry(&ec_cmd_q, struct ec_cmd_desc, node); + list_del(&desc->node); + } + spin_unlock_irqrestore(&ec_cmd_q_lock, flags); + + /* Do we actually have anything to do? */ + if (!desc) + return; + + /* Protect the EC hw with a mutex; only run one cmd at a time */ + mutex_lock(&ec_cb_lock); + desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen, + desc->outbuf, desc->outlen, ec_cb_arg); + mutex_unlock(&ec_cb_lock); + + /* Finished, wake up olpc_ec_cmd() */ + complete(&desc->finished); + + /* Run the worker thread again in case there are more cmds pending */ + schedule_work(&ec_worker); +} + +/* + * Throw a cmd descripter onto the list. We now have SMP OLPC machines, so + * locking is pretty critical. + */ +static void queue_ec_descriptor(struct ec_cmd_desc *desc) +{ + unsigned long flags; + + INIT_LIST_HEAD(&desc->node); + + spin_lock_irqsave(&ec_cmd_q_lock, flags); + list_add_tail(&desc->node, &ec_cmd_q); + spin_unlock_irqrestore(&ec_cmd_q_lock, flags); + + schedule_work(&ec_worker); +} + int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen) { - /* Currently a stub; this will be expanded upon later. */ - return olpc_ec_cmd_x86(cmd, inbuf, inlen, outbuf, outlen); + struct ec_cmd_desc desc; + + /* XXX: this will be removed in later patches */ + /* Are we using old-style callers? */ + if (!ec_driver || !ec_driver->ec_cmd) + return olpc_ec_cmd_x86(cmd, inbuf, inlen, outbuf, outlen); + + /* Ensure a driver and ec hook have been registered */ + if (WARN_ON(!ec_driver || !ec_driver->ec_cmd)) + return -ENODEV; + + might_sleep(); + + desc.cmd = cmd; + desc.inbuf = inbuf; + desc.outbuf = outbuf; + desc.inlen = inlen; + desc.outlen = outlen; + desc.err = 0; + init_completion(&desc.finished); + + queue_ec_descriptor(&desc); + + /* Timeouts must be handled in the platform-specific EC hook */ + wait_for_completion(&desc.finished); + + /* The worker thread dequeues the cmd; no need to do anything here */ + return desc.err; } EXPORT_SYMBOL_GPL(olpc_ec_cmd); diff --git a/include/linux/olpc-ec.h b/include/linux/olpc-ec.h index 6d4e426d9fdc..231e96f5dfe2 100644 --- a/include/linux/olpc-ec.h +++ b/include/linux/olpc-ec.h @@ -14,8 +14,14 @@ #define EC_SCI_QUERY 0x84 #define EC_EXT_SCI_QUERY 0x85 +struct olpc_ec_driver { + int (*ec_cmd)(u8, u8 *, size_t, u8 *, size_t, void *); +}; + #ifdef CONFIG_OLPC +extern void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg); + extern int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen); -- 2.34.1