brcmfmac: Use atomic functions for intstatus update.

The intstatus in sdio code can be updated from different
threads. To protect intstatus access, atomic functions are
used. One of them is set_bit, but this function is not
guaranteed atomic on all platforms. The loop was replaced
with local created OR function.

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: John W. Linville <linville@tuxdriver.com>

1 files changed, 15 insertions, 14 deletions

diff --git a/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c b/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c
index 70bab5e089eb..a111b6fbbeba 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c
@@ -2439,12 +2439,21 @@ static inline void brcmf_sdio_clrintr(struct brcmf_sdio *bus)
         }
 }
 
+static void atomic_orr(int val, atomic_t *v)
+{
+        int old_val;
+
+        old_val = atomic_read(v);
+        while (atomic_cmpxchg(v, old_val, val | old_val) != old_val)
+                old_val = atomic_read(v);
+}
+
 static int brcmf_sdio_intr_rstatus(struct brcmf_sdio *bus)
 {
         struct brcmf_core *buscore;
         u32 addr;
         unsigned long val;
-        int n, ret;
+        int ret;
 
         buscore = brcmf_chip_get_core(bus->ci, BCMA_CORE_SDIO_DEV);
         addr = buscore->base + offsetof(struct sdpcmd_regs, intstatus);
@@ -2452,7 +2461,7 @@ static int brcmf_sdio_intr_rstatus(struct brcmf_sdio *bus)
         val = brcmf_sdiod_regrl(bus->sdiodev, addr, &ret);
         bus->sdcnt.f1regdata++;
         if (ret != 0)
-                val = 0;
+                return ret;
 
         val &= bus->hostintmask;
         atomic_set(&bus->fcstate, !!(val & I_HMB_FC_STATE));
@@ -2461,13 +2470,7 @@ static int brcmf_sdio_intr_rstatus(struct brcmf_sdio *bus)
         if (val) {
                 brcmf_sdiod_regwl(bus->sdiodev, addr, val, &ret);
                 bus->sdcnt.f1regdata++;
-        }
-
-        if (ret) {
-                atomic_set(&bus->intstatus, 0);
-        } else if (val) {
-                for_each_set_bit(n, &val, 32)
-                        set_bit(n, (unsigned long *)&bus->intstatus.counter);
+                atomic_orr(val, &bus->intstatus);
         }
 
         return ret;
@@ -2479,7 +2482,7 @@ static void brcmf_sdio_dpc(struct brcmf_sdio *bus)
         unsigned long intstatus;
         uint txlimit = bus->txbound;    /* Tx frames to send before resched */
         uint framecnt;                  /* Temporary counter of tx/rx frames */
-        int err = 0, n;
+        int err = 0;
 
         brcmf_dbg(TRACE, "Enter\n");
 
@@ -2583,10 +2586,8 @@ static void brcmf_sdio_dpc(struct brcmf_sdio *bus)
         }
 
         /* Keep still-pending events for next scheduling */
-        if (intstatus) {
-                for_each_set_bit(n, &intstatus, 32)
-                        set_bit(n, (unsigned long *)&bus->intstatus.counter);
-        }
+        if (intstatus)
+                atomic_orr(intstatus, &bus->intstatus);
 
         brcmf_sdio_clrintr(bus);