[RFC 1/2] powerpc/powernv: Get a unique token for async completions

From: Shilpasri G Bhat
Date: Mon Jun 05 2017 - 02:15:17 EST


This patch adds support to get a unique token for async completion
requests. This will be used for creating non-repititive request
handles for consecutive requests in OPAL-OCC command/response
interface.

Signed-off-by: Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/opal.h | 1 +
arch/powerpc/platforms/powernv/opal-async.c | 46 +++++++++++++++++++++++++++++
2 files changed, 47 insertions(+)

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 588fb1c..03ed493 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -293,6 +293,7 @@ extern int opal_message_notifier_unregister(enum opal_msg_type msg_type,

extern int __opal_async_get_token(void);
extern int opal_async_get_token_interruptible(void);
+extern int opal_async_get_unique_token_interruptible(int last_token);
extern int __opal_async_release_token(int token);
extern int opal_async_release_token(int token);
extern int opal_async_wait_response(uint64_t token, struct opal_msg *msg);
diff --git a/arch/powerpc/platforms/powernv/opal-async.c b/arch/powerpc/platforms/powernv/opal-async.c
index 83bebee..8caeea2 100644
--- a/arch/powerpc/platforms/powernv/opal-async.c
+++ b/arch/powerpc/platforms/powernv/opal-async.c
@@ -73,6 +73,52 @@ int opal_async_get_token_interruptible(void)
}
EXPORT_SYMBOL_GPL(opal_async_get_token_interruptible);

+static int __opal_async_get_new_token(int last_token)
+{
+ unsigned long flags;
+ int token;
+
+ spin_lock_irqsave(&opal_async_comp_lock, flags);
+ token = find_next_bit(opal_async_complete_map, opal_max_async_tokens,
+ last_token + 1);
+ if (token >= opal_max_async_tokens) {
+ token = find_first_bit(opal_async_complete_map,
+ opal_max_async_tokens);
+ if (token >= opal_max_async_tokens || token == last_token) {
+ token = -EBUSY;
+ goto out;
+ }
+ }
+
+ pr_debug("%s token = %d\n", __func__, token);
+ if (__test_and_set_bit(token, opal_async_token_map)) {
+ token = -EBUSY;
+ goto out;
+ }
+
+ __clear_bit(token, opal_async_complete_map);
+
+out:
+ spin_unlock_irqrestore(&opal_async_comp_lock, flags);
+ return token;
+}
+
+int opal_async_get_unique_token_interruptible(int last_token)
+{
+ int token;
+
+ /* Wait until a token is available */
+ if (down_interruptible(&opal_async_sem))
+ return -ERESTARTSYS;
+
+ token = __opal_async_get_new_token(last_token);
+ if (token < 0)
+ up(&opal_async_sem);
+
+ return token;
+}
+EXPORT_SYMBOL_GPL(opal_async_get_unique_token_interruptible);
+
int __opal_async_release_token(int token)
{
unsigned long flags;
--
1.8.3.1