mwifiex: sdio: reset adapter using mmc_hw_reset

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 <afenkart@gmail.com>
Acked-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/mwifiex/sdio.c b/drivers/net/wireless/mwifiex/sdio.c
index a0b121f3460c871eefca6fd30d79a3217ef401c8..e4c35ee12782dade98cd122f4bc5825d00d1c56c 100644 (file)
--- 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 6f645cf47369baddaa10bc6489837fa914a14a57..c44da610541afa603f2abcfa1e85ff42959f0013 100644 (file)
--- 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 {