[PATCH net 2/4] tg3: Select PLL clock when preparing for shutdown

[Pavan Chebbi <pavan.chebbi@broadcom.com>]

When the 5720 was linked up at 1G, it may fail to wake up on a
single Magic packet.  This is a hardware issue, which can be avoided
by locking the PLL clock source before shutdown.

When preparing for power down with Wake-on-LAN enabled, if the link was
up at 1G, set CPMU_PLL_TLP_CLCK_SRC_NCSI_PLL in TG3_CPMU_PLL_CTRL_STAT,
so that the NCSI PLL locks on the TLP clock.  The setting is cleared on
the next chip reset.

This was reported by a user, who confirmed that this change fixes it.

Fixes: ba1f3c76d760 ("tg3: Enable 5720 support")
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
---
 drivers/net/ethernet/broadcom/tg3.c | 14 ++++++++++++++
 drivers/net/ethernet/broadcom/tg3.h |  6 +++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 2cf9d2ea069b..e9b48e58fdd4 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -4127,6 +4127,14 @@ static void tg3_power_down_prepare(struct tg3 *tp)
 	if (device_should_wake) {
 		u32 mac_mode;
 
+		if (tg3_asic_rev(tp) == ASIC_REV_5720 &&
+		    tp->link_config.active_speed == SPEED_1000) {
+			u32 val = tr32(TG3_CPMU_PLL_CTRL_STAT);
+
+			tw32(TG3_CPMU_PLL_CTRL_STAT,
+			     val | CPMU_PLL_TLP_CLCK_SRC_NCSI_PLL);
+		}
+
 		if (!(tp->phy_flags & TG3_PHYFLG_PHY_SERDES)) {
 			if (do_low_power &&
 			    !(tp->phy_flags & TG3_PHYFLG_IS_FET)) {
@@ -9394,6 +9402,12 @@ static int tg3_chip_reset(struct tg3 *tp)
 
 	tg3_restore_clk(tp);
 
+	if (tg3_asic_rev(tp) == ASIC_REV_5720) {
+		val = tr32(TG3_CPMU_PLL_CTRL_STAT);
+		tw32(TG3_CPMU_PLL_CTRL_STAT,
+		     val & ~CPMU_PLL_TLP_CLCK_SRC_NCSI_PLL);
+	}
+
 	/* Increase the core clock speed to fix tx timeout issue for 5762
 	 * with 100Mbps link speed.
 	 */
diff --git a/drivers/net/ethernet/broadcom/tg3.h b/drivers/net/ethernet/broadcom/tg3.h
index a9e7f88fa26d..631bacc515ab 100644
--- a/drivers/net/ethernet/broadcom/tg3.h
+++ b/drivers/net/ethernet/broadcom/tg3.h
@@ -1168,7 +1168,11 @@
 #define  CPMU_CLCK_STAT_MAC_CLCK_62_5	 0x00000000
 #define  CPMU_CLCK_STAT_MAC_CLCK_12_5	 0x00110000
 #define  CPMU_CLCK_STAT_MAC_CLCK_6_25	 0x00130000
-/* 0x3634 --> 0x365c unused */
+/* 0x3634 unused */
+
+#define TG3_CPMU_PLL_CTRL_STAT		0x00003638
+#define  CPMU_PLL_TLP_CLCK_SRC_NCSI_PLL	0x04000000
+/* 0x363c --> 0x365c unused */
 
 #define TG3_CPMU_MUTEX_REQ		0x0000365c
 #define  CPMU_MUTEX_REQ_DRIVER		 0x00001000
-- 
2.52.0