[PATCH 02/32] staging: brcm80211: new Kconfig item to enable IO reordering fix

["Arend van Spriel" <arend@broadcom.com>]

From: Roland Vossen <rvossen@broadcom.com>

bcm4716 (which includes 4717 & 4718), plus 4706 on PCIe can reorder
transactions. As a fix, a read after write is performed on certain places
in the code. Older chips and the newer 5357 family don't require this fix.

Cc: devel@linuxdriverproject.org
Cc: linux-wireless@vger.kernel.org
Reviewed-by: Henry Ptasinski <henryp@broadcom.com>
Reviewed-by: Brett Rudley <brudley@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
---
 drivers/staging/brcm80211/Kconfig                  |    8 ++++++++
 .../staging/brcm80211/brcmsmac/phy/wlc_phy_cmn.c   |    4 ++--
 drivers/staging/brcm80211/include/bcmutils.h       |   11 +++++++++++
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/brcm80211/Kconfig b/drivers/staging/brcm80211/Kconfig
index f4cf9b2..a11ffc7 100644
--- a/drivers/staging/brcm80211/Kconfig
+++ b/drivers/staging/brcm80211/Kconfig
@@ -36,3 +36,11 @@ config BRCMDBG
 	depends on BRCMSMAC || BRCMFMAC
 	---help---
 	  Selecting this enables additional code for debug purposes.
+
+config BRCM_FIX_IO_ORDER
+	bool "Broadcom I/O order fix"
+	default n
+	depends on BRCMSMAC
+	---help---
+	  Select this for for platforms running on bcm4706, 4716, 4717 or 4718.
+	  It resolves an I/O issue with the PCIe core used in these chips.
diff --git a/drivers/staging/brcm80211/brcmsmac/phy/wlc_phy_cmn.c b/drivers/staging/brcm80211/brcmsmac/phy/wlc_phy_cmn.c
index 6cba4df..b3c5f07 100644
--- a/drivers/staging/brcm80211/brcmsmac/phy/wlc_phy_cmn.c
+++ b/drivers/staging/brcm80211/brcmsmac/phy/wlc_phy_cmn.c
@@ -412,7 +412,7 @@ void write_phy_reg(phy_info_t *pi, u16 addr, u16 val)
 
 	regs = pi->regs;
 
-#ifdef __mips__
+#ifdef CONFIG_BRCM_FIX_IO_ORDER
 	W_REG(&regs->phyregaddr, addr);
 	(void)R_REG(&regs->phyregaddr);
 	W_REG(&regs->phyregdata, val);
@@ -427,7 +427,7 @@ void write_phy_reg(phy_info_t *pi, u16 addr, u16 val)
 			(void)R_REG(&regs->phyversion);
 		}
 	}
-#endif
+#endif /* CONFIG_BRCM_FIX_IO_ORDER */
 }
 
 void and_phy_reg(phy_info_t *pi, u16 addr, u16 val)
diff --git a/drivers/staging/brcm80211/include/bcmutils.h b/drivers/staging/brcm80211/include/bcmutils.h
index 224d4ce..a4a2a8d 100644
--- a/drivers/staging/brcm80211/include/bcmutils.h
+++ b/drivers/staging/brcm80211/include/bcmutils.h
@@ -367,6 +367,17 @@ extern void bcm_prpkt(const char *msg, struct sk_buff *p0);
 	} while (0)
 #endif				/* __BIG_ENDIAN */
 
+#ifdef CONFIG_BRCM_FIX_IO_ORDER
+/*
+ * bcm4716 (which includes 4717 & 4718), plus 4706 on PCIe can reorder
+ * transactions. As a fix, a read after write is performed on certain places
+ * in the code. Older chips and the newer 5357 family don't require this fix.
+ */
+#define W_REG_FLUSH(r, v)	{ W_REG((r), (v)); (void)R_REG(r); }
+#else
+#define W_REG_FLUSH(r, v)	W_REG((r), (v))
+#endif				/* CONFIG_BRCM_FIX_IO_ORDER */
+
 #define AND_REG(r, v)	W_REG((r), R_REG(r) & (v))
 #define OR_REG(r, v)	W_REG((r), R_REG(r) | (v))
 
-- 
1.7.4.1