brcmfmac: prevent possible deadlock on resuming SDIO device.

When the system is resumed a deadlock can occur when DPC gets
entered before resume is complete. This patch fixes this by
properly checking the suspend state outside the claim_host code
block.

Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Daniel (Deognyoun) Kim <dekim@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

3 files changed, 18 insertions, 35 deletions

diff --git a/drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c b/drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c
index 00ba90b89455..8ba60f6f4915 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c
@@ -97,25 +97,6 @@ static void brcmf_sdiod_dummy_irqhandler(struct sdio_func *func)
 {
 }
 
-static bool brcmf_sdiod_pm_resume_error(struct brcmf_sdio_dev *sdiodev)
-{
-        bool is_err = false;
-#ifdef CONFIG_PM_SLEEP
-        is_err = atomic_read(&sdiodev->suspend);
-#endif
-        return is_err;
-}
-
-static void brcmf_sdiod_pm_resume_wait(struct brcmf_sdio_dev *sdiodev,
-                                       wait_queue_head_t *wq)
-{
-#ifdef CONFIG_PM_SLEEP
-        int retry = 0;
-        while (atomic_read(&sdiodev->suspend) && retry++ != 30)
-                wait_event_timeout(*wq, false, HZ/100);
-#endif
-}
-
 int brcmf_sdiod_intr_register(struct brcmf_sdio_dev *sdiodev)
 {
         int ret = 0;
@@ -244,10 +225,6 @@ static int brcmf_sdiod_request_data(struct brcmf_sdio_dev *sdiodev, u8 fn,
         brcmf_dbg(SDIO, "rw=%d, func=%d, addr=0x%05x, nbytes=%d\n",
                   write, fn, addr, regsz);
 
-        brcmf_sdiod_pm_resume_wait(sdiodev, &sdiodev->request_word_wait);
-        if (brcmf_sdiod_pm_resume_error(sdiodev))
-                return -EIO;
-
         /* only allow byte access on F0 */
         if (WARN_ON(regsz > 1 && !fn))
                 return -EINVAL;
@@ -462,10 +439,6 @@ static int brcmf_sdiod_buffrw(struct brcmf_sdio_dev *sdiodev, uint fn,
         unsigned int req_sz;
         int err;
 
-        brcmf_sdiod_pm_resume_wait(sdiodev, &sdiodev->request_buffer_wait);
-        if (brcmf_sdiod_pm_resume_error(sdiodev))
-                return -EIO;
-
         /* Single skb use the standard mmc interface */
         req_sz = pkt->len + 3;
         req_sz &= (uint)~3;
@@ -516,10 +489,6 @@ static int brcmf_sdiod_sglist_rw(struct brcmf_sdio_dev *sdiodev, uint fn,
         if (!pktlist->qlen)
                 return -EINVAL;
 
-        brcmf_sdiod_pm_resume_wait(sdiodev, &sdiodev->request_buffer_wait);
-        if (brcmf_sdiod_pm_resume_error(sdiodev))
-                return -EIO;
-
         target_list = pktlist;
         /* for host with broken sg support, prepare a page aligned list */
         __skb_queue_head_init(&local_list);
@@ -1077,8 +1046,6 @@ static int brcmf_ops_sdio_probe(struct sdio_func *func,
 #endif
 
         atomic_set(&sdiodev->suspend, false);
-        init_waitqueue_head(&sdiodev->request_word_wait);
-        init_waitqueue_head(&sdiodev->request_buffer_wait);
 
         brcmf_dbg(SDIO, "F2 found, calling brcmf_sdiod_probe...\n");
         err = brcmf_sdiod_probe(sdiodev);
diff --git a/drivers/net/wireless/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/brcm80211/brcmfmac/sdio.c
index 99a37765888d..2c4f0ccd3b70 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/sdio.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/sdio.c
@@ -2609,6 +2609,21 @@ static int brcmf_sdio_intr_rstatus(struct brcmf_sdio *bus)
         return ret;
 }
 
+static int brcmf_sdio_pm_resume_wait(struct brcmf_sdio_dev *sdiodev)
+{
+#ifdef CONFIG_PM_SLEEP
+        int retry;
+
+        /* Wait for possible resume to complete */
+        retry = 0;
+        while ((atomic_read(&sdiodev->suspend)) && (retry++ != 50))
+                msleep(20);
+        if (atomic_read(&sdiodev->suspend))
+                return -EIO;
+#endif
+        return 0;
+}
+
 static void brcmf_sdio_dpc(struct brcmf_sdio *bus)
 {
         u32 newstatus = 0;
@@ -2619,6 +2634,9 @@ static void brcmf_sdio_dpc(struct brcmf_sdio *bus)
 
         brcmf_dbg(TRACE, "Enter\n");
 
+        if (brcmf_sdio_pm_resume_wait(bus->sdiodev))
+                return;
+
         sdio_claim_host(bus->sdiodev->func[1]);
 
         /* If waiting for HTAVAIL, check status */
diff --git a/drivers/net/wireless/brcm80211/brcmfmac/sdio.h b/drivers/net/wireless/brcm80211/brcmfmac/sdio.h
index 8eb42620129c..82494df541d4 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/sdio.h
+++ b/drivers/net/wireless/brcm80211/brcmfmac/sdio.h
@@ -169,8 +169,6 @@ struct brcmf_sdio_dev {
         u32 sbwad;                      /* Save backplane window address */
         struct brcmf_sdio *bus;
         atomic_t suspend;               /* suspend flag */
-        wait_queue_head_t request_word_wait;
-        wait_queue_head_t request_buffer_wait;
         struct device *dev;
         struct brcmf_bus *bus_if;
         struct brcmfmac_sdio_platform_data *pdata;