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 <dilinger@xxxxxxxxxx>
---
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 4202603..44e6a4f 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 <linux/completion.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/olpc-ec.h>
#include <asm/olpc.h>
+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 6d4e426..231e96f 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);
--
1.7.2.5
--
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