tg3: Disable CLKREQ in L2

This patch disables CLKREQ in L2 to workaround a chipset bug.
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -7642,6 +7642,20 @@ static int tg3_reset_hw(struct tg3 *tp, int reset_phy)
 		tw32(GRC_MODE, grc_mode);
 	}
 
+	if (tp->pci_chip_rev_id == CHIPREV_ID_57765_A0) {
+		u32 grc_mode = tr32(GRC_MODE);
+
+		/* Access the lower 1K of PL PCIE block registers. */
+		val = grc_mode & ~GRC_MODE_PCIE_PORT_MASK;
+		tw32(GRC_MODE, val | GRC_MODE_PCIE_PL_SEL);
+
+		val = tr32(TG3_PCIE_TLDLPL_PORT + TG3_PCIE_PL_LO_PHYCTL5);
+		tw32(TG3_PCIE_TLDLPL_PORT + TG3_PCIE_PL_LO_PHYCTL5,
+		     val | TG3_PCIE_PL_LO_PHYCTL5_DIS_L2CLKREQ);
+
+		tw32(GRC_MODE, grc_mode);
+	}
+
 	/* This works around an issue with Athlon chipsets on
 	 * B3 tigon3 silicon.  This bit has no effect on any
 	 * other revision.  But do not set this on PCI Express

drivers/net/tg3.h

@@ -1854,6 +1854,8 @@
 #define TG3_PCIE_TLDLPL_PORT		0x00007c00
 #define TG3_PCIE_PL_LO_PHYCTL1		 0x00000004
 #define TG3_PCIE_PL_LO_PHYCTL1_L1PLLPD_EN	  0x00001000
+#define TG3_PCIE_PL_LO_PHYCTL5		 0x00000014
+#define TG3_PCIE_PL_LO_PHYCTL5_DIS_L2CLKREQ	  0x80000000
 
 /* OTP bit definitions */
 #define TG3_OTP_AGCTGT_MASK		0x000000e0