Return-path: Received: from mail-wi0-f177.google.com ([209.85.212.177]:36415 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751454AbbGPQuF (ORCPT ); Thu, 16 Jul 2015 12:50:05 -0400 Received: by widjy10 with SMTP id jy10so20970814wid.1 for ; Thu, 16 Jul 2015 09:50:04 -0700 (PDT) From: Andreas Fenkart To: linux-wireless@vger.kernel.org Cc: Amitkumar Karwar , Avinash Patil , Andreas Fenkart Subject: [PATCH] mwifiex: sdio: reset adapter using mmc_hw_reset Date: Thu, 16 Jul 2015 18:50:01 +0200 Message-Id: <1437065401-20245-1-git-send-email-afenkart@gmail.com> (sfid-20150716_185010_461782_F9FDE0BA) Sender: linux-wireless-owner@vger.kernel.org List-ID: Since 1fb654fd97ff("mmc: sdio: add reset callback to bus operations"), sdio cards can be power cycled using mmc_hw_reset. The use mmc_remove_host/mmc_add_host is discouraged, because these are internal functions to the mmc core and should only be used by mmc hosts Signed-off-by: Andreas Fenkart --- drivers/net/wireless/mwifiex/sdio.c | 51 ++++++++++++++++++++++++++----------- drivers/net/wireless/mwifiex/sdio.h | 3 +++ 2 files changed, 39 insertions(+), 15 deletions(-) diff --git a/drivers/net/wireless/mwifiex/sdio.c b/drivers/net/wireless/mwifiex/sdio.c index a0b121f..e4c35ee 100644 --- a/drivers/net/wireless/mwifiex/sdio.c +++ b/drivers/net/wireless/mwifiex/sdio.c @@ -91,6 +91,7 @@ mwifiex_sdio_probe(struct sdio_func *func, const struct sdio_device_id *id) return -ENOMEM; card->func = func; + card->device_id = id; func->card->quirks |= MMC_QUIRK_BLKSZ_FOR_BYTE_MODE; @@ -2107,26 +2108,46 @@ mwifiex_update_mp_end_port(struct mwifiex_adapter *adapter, u16 port) port, card->mp_data_port_mask); } +static void mwifiex_recreate_adapter(struct sdio_mmc_card *card) +{ + struct sdio_func *func = card->func; + const struct sdio_device_id *device_id = card->device_id; + + /* TODO mmc_hw_reset does not require destroying and re-probing the + * whole adapter. Hence there was no need to for this rube-goldberg + * design to reload the fw from an external workqueue. If we don't + * destroy the adapter we could reload the fw from + * mwifiex_main_work_queue directly. + * The real difficulty with fw reset is to restore all the user + * settings applied through ioctl. By destroying and recreating the + * adapter, we take the easy way out, since we rely on user space to + * restore them. We assume that user space will treat the new + * incarnation of the adapter(interfaces) as if they had been just + * discovered and initializes them from scratch. + */ + + mwifiex_sdio_remove(func); + + /* power cycle the adapter */ + sdio_claim_host(func); + mmc_hw_reset(func->card->host); + sdio_release_host(func); + + mwifiex_sdio_probe(func, device_id); +} + static struct mwifiex_adapter *save_adapter; static void mwifiex_sdio_card_reset_work(struct mwifiex_adapter *adapter) { struct sdio_mmc_card *card = adapter->card; - struct mmc_host *target = card->func->card->host; - - /* The actual reset operation must be run outside of driver thread. - * This is because mmc_remove_host() will cause the device to be - * instantly destroyed, and the driver then needs to end its thread, - * leading to a deadlock. - * - * We run it in a totally independent workqueue. - */ - mwifiex_dbg(adapter, WARN, "Resetting card...\n"); - mmc_remove_host(target); - /* 200ms delay is based on experiment with sdhci controller */ - mdelay(200); - target->rescan_entered = 0; /* rescan non-removable cards */ - mmc_add_host(target); + /* TODO card pointer is unprotected. If the adapter is removed + * physically, sdio core might trigger mwifiex_sdio_remove, before this + * workqueue is run, which will destroy the adapter struct. When this + * workqueue eventually exceutes it will dereference an invalid adapter + * pointer + */ + mwifiex_recreate_adapter(card); } /* This function read/write firmware */ diff --git a/drivers/net/wireless/mwifiex/sdio.h b/drivers/net/wireless/mwifiex/sdio.h index 6f645cf..c44da61 100644 --- a/drivers/net/wireless/mwifiex/sdio.h +++ b/drivers/net/wireless/mwifiex/sdio.h @@ -262,6 +262,9 @@ struct sdio_mmc_card { struct mwifiex_sdio_mpa_tx mpa_tx; struct mwifiex_sdio_mpa_rx mpa_rx; + + /* needed for card reset */ + const struct sdio_device_id *device_id; }; struct mwifiex_sdio_device { -- 2.1.4