[PATCH 4.2 07/30] net: dsa: bcm_sf2: Fix ageing conditions and operation

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Florian Fainelli <f.fainelli@gmail.com>

[ Upstream commit 39797a279d62972cd914ef580fdfacb13e508bf8 ]

The comparison check between cur_hw_state and hw_state is currently
invalid because cur_hw_state is right shifted by G_MISTP_SHIFT, while
hw_state is not, so we end-up comparing bits 2:0 with bits 7:5, which is
going to cause an additional aging to occur. Fix this by not shifting
cur_hw_state while reading it, but instead, mask the value with the
appropriately shitfted bitmask.

The other problem with the fast-ageing process is that we did not set
the EN_AGE_DYNAMIC bit to request the ageing to occur for dynamically
learned MAC addresses. Finally, write back 0 to the FAST_AGE_CTRL
register to avoid leaving spurious bits sets from one operation to the
other.

Fixes: 12f460f23423 ("net: dsa: bcm_sf2: add HW bridging support")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/dsa/bcm_sf2.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/net/dsa/bcm_sf2.c
+++ b/drivers/net/dsa/bcm_sf2.c
@@ -418,7 +418,7 @@ static int bcm_sf2_sw_fast_age_port(stru
 	core_writel(priv, port, CORE_FAST_AGE_PORT);
 
 	reg = core_readl(priv, CORE_FAST_AGE_CTRL);
-	reg |= EN_AGE_PORT | FAST_AGE_STR_DONE;
+	reg |= EN_AGE_PORT | EN_AGE_DYNAMIC | FAST_AGE_STR_DONE;
 	core_writel(priv, reg, CORE_FAST_AGE_CTRL);
 
 	do {
@@ -432,6 +432,8 @@ static int bcm_sf2_sw_fast_age_port(stru
 	if (!timeout)
 		return -ETIMEDOUT;
 
+	core_writel(priv, 0, CORE_FAST_AGE_CTRL);
+
 	return 0;
 }
 
@@ -507,7 +509,7 @@ static int bcm_sf2_sw_br_set_stp_state(s
 	u32 reg;
 
 	reg = core_readl(priv, CORE_G_PCTL_PORT(port));
-	cur_hw_state = reg >> G_MISTP_STATE_SHIFT;
+	cur_hw_state = reg & (G_MISTP_STATE_MASK << G_MISTP_STATE_SHIFT);
 
 	switch (state) {
 	case BR_STATE_DISABLED:
@@ -531,10 +533,12 @@ static int bcm_sf2_sw_br_set_stp_state(s
 	}
 
 	/* Fast-age ARL entries if we are moving a port from Learning or
-	 * Forwarding state to Disabled, Blocking or Listening state
+	 * Forwarding (cur_hw_state) state to Disabled, Blocking or Listening
+	 * state (hw_state)
 	 */
 	if (cur_hw_state != hw_state) {
-		if (cur_hw_state & 4 && !(hw_state & 4)) {
+		if (cur_hw_state >= G_MISTP_LEARN_STATE &&
+		    hw_state <= G_MISTP_LISTEN_STATE) {
 			ret = bcm_sf2_sw_fast_age_port(ds, port);
 			if (ret) {
 				pr_err("%s: fast-ageing failed\n", __func__);