From: Peter Oh <poh@qca.qualcomm.com>
To: ath10k@lists.infradead.org
Subject: Re: [PATCH v2] ath10k: Replace ioread with mb to drain write buffer
Date: Fri, 30 Jan 2015 16:22:21 -0800 [thread overview]
Message-ID: <54CC203D.9030309@qca.qualcomm.com> (raw)
In-Reply-To: <7a87e5df81499e4d26a4f8bedf76ed3250a6f7bb.1422663244.git.poh@qca.qualcomm.com>
On 01/30/2015 04:14 PM, Peter Oh wrote:
> 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();
It figured out that ath10k_pci_read32() use dsb with 'st' while wmb() is
use with 'sy'.
So updated it from wmb() to mb() for the same effect as ath10k_pci_read32().
> }
>
> 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)
Thanks,
Peter
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next prev parent reply other threads:[~2015-01-31 0:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-31 0:14 [PATCH v2] ath10k: Replace ioread with mb to drain write buffer Peter Oh
2015-01-31 0:22 ` Peter Oh [this message]
2015-02-06 8:58 ` Jakub Kiciński
2015-02-06 14:53 ` Jakub Kiciński
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