r8169: rename rtl_csi_access_enable to rtl_set_aspm_entry_latency

Rename the function to reflect what it's doing. Also add a description
of the register values as kindly provided by Realtek.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169_main.c

@@ -2598,7 +2598,7 @@ static u32 rtl_csi_read(struct rtl8169_private *tp, int addr)
 		RTL_R32(tp, CSIDR) : ~0;
 }
 
-static void rtl_csi_access_enable(struct rtl8169_private *tp, u8 val)
+static void rtl_set_aspm_entry_latency(struct rtl8169_private *tp, u8 val)
 {
 	struct pci_dev *pdev = tp->pci_dev;
 	u32 csi;
@@ -2606,6 +2606,8 @@ static void rtl_csi_access_enable(struct rtl8169_private *tp, u8 val)
 	/* According to Realtek the value at config space address 0x070f
 	 * controls the L0s/L1 entrance latency. We try standard ECAM access
 	 * first and if it fails fall back to CSI.
+	 * bit 0..2: L0: 0 = 1us, 1 = 2us .. 6 = 7us, 7 = 7us (no typo)
+	 * bit 3..5: L1: 0 = 1us, 1 = 2us .. 6 = 64us, 7 = 64us
 	 */
 	if (pdev->cfg_size > 0x070f &&
 	    pci_write_config_byte(pdev, 0x070f, val) == PCIBIOS_SUCCESSFUL)
@@ -2619,7 +2621,8 @@ static void rtl_csi_access_enable(struct rtl8169_private *tp, u8 val)
 
 static void rtl_set_def_aspm_entry_latency(struct rtl8169_private *tp)
 {
-	rtl_csi_access_enable(tp, 0x27);
+	/* L0 7us, L1 16us */
+	rtl_set_aspm_entry_latency(tp, 0x27);
 }
 
 struct ephy_info {
@@ -3502,8 +3505,8 @@ static void rtl_hw_start_8106(struct rtl8169_private *tp)
 	RTL_W8(tp, MCU, RTL_R8(tp, MCU) | EN_NDP | EN_OOB_RESET);
 	RTL_W8(tp, DLLPR, RTL_R8(tp, DLLPR) & ~PFM_EN);
 
-	/* The default value is 0x13. Change it to 0x2f */
-	rtl_csi_access_enable(tp, 0x2f);
+	/* L0 7us, L1 32us - needed to avoid issues with link-up detection */
+	rtl_set_aspm_entry_latency(tp, 0x2f);
 
 	rtl_eri_write(tp, 0x1d0, ERIAR_MASK_0011, 0x0000);