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authorStanislaw Gruszka <sgruszka@redhat.com>2012-02-13 11:23:10 +0100
committerJohn W. Linville <linville@tuxdriver.com>2012-02-22 14:51:12 -0500
commit4e5ea2088b699ae86ffd96b53b916a3966535fcb (patch)
tree33af73e283a223658d20ee475cae1bbe4d16862c /drivers/net/wireless/iwlegacy/common.h
parent1e0f32a43ae652eaa5b23dc06852938555cb8da1 (diff)
iwlegacy: cleanup/fix memory barriers
wmb(), rmb() are not needed when writel(), readl() are used as accessors for MMIO. We use them indirectly via iowrite32(), ioread32(). What is needed mmiowb(), for synchronizing writes coming from different CPUs on PCIe bridge (see in patch comments). This fortunately is not needed on x86, where mmiowb() is just defined as compiler barrier. As iwlegacy devices are most likely not used on anything other than x86, this is not so important fix. Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'drivers/net/wireless/iwlegacy/common.h')
-rw-r--r--drivers/net/wireless/iwlegacy/common.h9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/net/wireless/iwlegacy/common.h b/drivers/net/wireless/iwlegacy/common.h
index 1dfaa58acc4..df9b5b46283 100644
--- a/drivers/net/wireless/iwlegacy/common.h
+++ b/drivers/net/wireless/iwlegacy/common.h
@@ -2146,6 +2146,13 @@ static inline void
_il_release_nic_access(struct il_priv *il)
{
_il_clear_bit(il, CSR_GP_CNTRL, CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
+ /*
+ * In above we are reading CSR_GP_CNTRL register, what will flush any
+ * previous writes, but still want write, which clear MAC_ACCESS_REQ
+ * bit, be performed on PCI bus before any other writes scheduled on
+ * different CPUs (after we drop reg_lock).
+ */
+ mmiowb();
}
static inline u32
@@ -2179,7 +2186,6 @@ static inline u32
_il_rd_prph(struct il_priv *il, u32 reg)
{
_il_wr(il, HBUS_TARG_PRPH_RADDR, reg | (3 << 24));
- rmb();
return _il_rd(il, HBUS_TARG_PRPH_RDAT);
}
@@ -2187,7 +2193,6 @@ static inline void
_il_wr_prph(struct il_priv *il, u32 addr, u32 val)
{
_il_wr(il, HBUS_TARG_PRPH_WADDR, ((addr & 0x0000FFFF) | (3 << 24)));
- wmb();
_il_wr(il, HBUS_TARG_PRPH_WDAT, val);
}