net: ethernet: bgmac: init sequence bug

Fix a bug in the 'bgmac' driver init sequence that blind writes for init
sequence where it should preserve most bits other than the ones it is
deliberately manipulating.

The code now checks to see if the adapter needs to be brought out of
reset (where as before it was doing an IDM write to bring it out of
reset regardless of whether it was in reset or not).  Also, removed
unnecessary usleeps (as there is already a read present to flush the
IDM writes).

Signed-off-by: Zac Schroff <zschroff@broadcom.com>
Signed-off-by: Jon Mason <jon.mason@broadcom.com>
Fixes: f6a95a24957 ("net: ethernet: bgmac: Add platform device support")
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 9 deletions

diff --git a/drivers/net/ethernet/broadcom/bgmac-platform.c b/drivers/net/ethernet/broadcom/bgmac-platform.c
index 7b1af950f312..da1b8b225eb9 100644
--- a/drivers/net/ethernet/broadcom/bgmac-platform.c
+++ b/drivers/net/ethernet/broadcom/bgmac-platform.c
@@ -51,8 +51,7 @@ static void platform_bgmac_idm_write(struct bgmac *bgmac, u16 offset, u32 value)
 
 static bool platform_bgmac_clk_enabled(struct bgmac *bgmac)
 {
-	if ((bgmac_idm_read(bgmac, BCMA_IOCTL) &
-	     (BCMA_IOCTL_CLK | BCMA_IOCTL_FGC)) != BCMA_IOCTL_CLK)
+	if ((bgmac_idm_read(bgmac, BCMA_IOCTL) & BGMAC_CLK_EN) != BGMAC_CLK_EN)
 		return false;
 	if (bgmac_idm_read(bgmac, BCMA_RESET_CTL) & BCMA_RESET_CTL_RESET)
 		return false;
@@ -61,15 +60,25 @@ static bool platform_bgmac_clk_enabled(struct bgmac *bgmac)
 
 static void platform_bgmac_clk_enable(struct bgmac *bgmac, u32 flags)
 {
-	bgmac_idm_write(bgmac, BCMA_IOCTL,
-			(BCMA_IOCTL_CLK | BCMA_IOCTL_FGC | flags));
-	bgmac_idm_read(bgmac, BCMA_IOCTL);
+	u32 val;
 
-	bgmac_idm_write(bgmac, BCMA_RESET_CTL, 0);
-	bgmac_idm_read(bgmac, BCMA_RESET_CTL);
-	udelay(1);
+	/* The Reset Control register only contains a single bit to show if the
+	 * controller is currently in reset.  Do a sanity check here, just in
+	 * case the bootloader happened to leave the device in reset.
+	 */
+	val = bgmac_idm_read(bgmac, BCMA_RESET_CTL);
+	if (val) {
+		bgmac_idm_write(bgmac, BCMA_RESET_CTL, 0);
+		bgmac_idm_read(bgmac, BCMA_RESET_CTL);
+		udelay(1);
+	}
 
-	bgmac_idm_write(bgmac, BCMA_IOCTL, (BCMA_IOCTL_CLK | flags));
+	val = bgmac_idm_read(bgmac, BCMA_IOCTL);
+	/* Some bits of BCMA_IOCTL set by HW/ATF and should not change */
+	val |= flags & ~(BGMAC_AWCACHE | BGMAC_ARCACHE | BGMAC_AWUSER |
+			 BGMAC_ARUSER);
+	val |= BGMAC_CLK_EN;
+	bgmac_idm_write(bgmac, BCMA_IOCTL, val);
 	bgmac_idm_read(bgmac, BCMA_IOCTL);
 	udelay(1);
 }