On Thu, Jan 12, 2017 at 01:02:31PM -0800, Brian Norris wrote:
> Depending on system factors (e.g., the PCIe link PM state), the first
> read to wake up the Wifi firmware can take a long time. There is no
> reason to use a (blocking, non-posted) read at this point, so let's just
> use a write instead. Write vs. read doesn't matter functionality-wise --
> it's just a dummy operation.
>
> This has been shown to decrease the time spent blocking in this function
> on a Rockchip RK3399 SoC.
>
> Signed-off-by: Brian Norris <briannor...@chromium.org>
> ---
> drivers/net/wireless/marvell/mwifiex/pcie.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c
> b/drivers/net/wireless/marvell/mwifiex/pcie.c
> index 66226c615be0..435ba879ef29 100644
> --- a/drivers/net/wireless/marvell/mwifiex/pcie.c
> +++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
> @@ -458,7 +458,6 @@ static void mwifiex_delay_for_sleep_cookie(struct
> mwifiex_adapter *adapter,
> /* This function wakes up the card by reading fw_status register. */
> static int mwifiex_pm_wakeup_card(struct mwifiex_adapter *adapter)
> {
> - u32 fw_status;
> struct pcie_service_card *card = adapter->card;
> const struct mwifiex_pcie_card_reg *reg = card->pcie.reg;
>
> @@ -468,10 +467,10 @@ static int mwifiex_pm_wakeup_card(struct
> mwifiex_adapter *adapter)
> if (reg->sleep_cookie)
> mwifiex_pcie_dev_wakeup_delay(adapter);
>
> - /* Reading fw_status register will wakeup device */
> - if (mwifiex_read_reg(adapter, reg->fw_status, &fw_status)) {
> + /* Accessing fw_status register will wakeup device */
> + if (mwifiex_write_reg(adapter, reg->fw_status, 0)) {
As Amit noted to me elsewhere, the firmware only writes this status once
at FW init time to FIRMWARE_READY_PCIE, and we later check it in a few
places. So I noticed that this actually breaks re-probing the adapter
(e.g., 'rmmod mwifiex_pcie; modprobe mwifiex_pcie'); the second time,
we'll fail to find the FIRMWARE_READY_PCIE signature, and so we'll
abort.
I'll resend this patch with s/0/FIRMWARE_READY_PCIE/ instead.
Brian
> mwifiex_dbg(adapter, ERROR,
> - "Reading fw_status register failed\n");
> + "Writing fw_status register failed\n");
> return -1;
> }
>
> --
> 2.11.0.390.gc69c2f50cf-goog
>
