linux-wireless.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Peter Oh <poh@qca.qualcomm.com>
To: <ath10k@lists.infradead.org>
Cc: <linux-wireless@vger.kernel.org>
Subject: [PATCH v2] ath10k: Replace ioread with mb to drain write buffer
Date: Fri, 30 Jan 2015 16:14:30 -0800	[thread overview]
Message-ID: <7a87e5df81499e4d26a4f8bedf76ed3250a6f7bb.1422663244.git.poh@qca.qualcomm.com> (raw)

Using ioread() to perform draining write buffer is excessive.
Use compact API, mb(), that intended to be used for the case.
It reduces total 14 CPU clocks per interrupt.

Signed-off-by: Peter Oh <poh@qca.qualcomm.com>
---
 drivers/net/wireless/ath/ath10k/pci.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index e6972b0..f1e6980 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -353,10 +353,8 @@ static void ath10k_pci_disable_and_clear_legacy_irq(struct ath10k *ar)
 	ath10k_pci_write32(ar, SOC_CORE_BASE_ADDRESS + PCIE_INTR_CLR_ADDRESS,
 			   PCIE_INTR_FIRMWARE_MASK | PCIE_INTR_CE_MASK_ALL);
 
-	/* IMPORTANT: this extra read transaction is required to
-	 * flush the posted write buffer. */
-	(void)ath10k_pci_read32(ar, SOC_CORE_BASE_ADDRESS +
-				PCIE_INTR_ENABLE_ADDRESS);
+	/* drain write buffer */
+	mb();
 }
 
 static void ath10k_pci_enable_legacy_irq(struct ath10k *ar)
@@ -365,10 +363,8 @@ static void ath10k_pci_enable_legacy_irq(struct ath10k *ar)
 			   PCIE_INTR_ENABLE_ADDRESS,
 			   PCIE_INTR_FIRMWARE_MASK | PCIE_INTR_CE_MASK_ALL);
 
-	/* IMPORTANT: this extra read transaction is required to
-	 * flush the posted write buffer. */
-	(void)ath10k_pci_read32(ar, SOC_CORE_BASE_ADDRESS +
-				PCIE_INTR_ENABLE_ADDRESS);
+	/* drain write buffer */
+	mb();
 }
 
 static inline const char *ath10k_pci_get_irq_method(struct ath10k *ar)
-- 
1.9.1


             reply	other threads:[~2015-01-31  0:14 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-31  0:14 Peter Oh [this message]
2015-02-06  8:58 ` [PATCH v2] ath10k: Replace ioread with mb to drain write buffer Jakub Kiciński
2015-02-06 14:53   ` Jakub Kiciński

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=7a87e5df81499e4d26a4f8bedf76ed3250a6f7bb.1422663244.git.poh@qca.qualcomm.com \
    --to=poh@qca.qualcomm.com \
    --cc=ath10k@lists.infradead.org \
    --cc=linux-wireless@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).