stmmac: add the Energy Efficient Ethernet support

This patch adds the Energy Efficient Ethernet support to the stmmac.

Please see the driver's documentation for further details about this support
in the driver.

Thanks also goes to Rayagond Kokatanur for his first implementation.

Note:
 to clearly manage and expose the lpi interrupt status and eee ethtool
 stats I've had to do some modifications to the driver's design and I
 found really useful to move other parts of the code (e.g. mmc irq stat)
 in the main directly. So this means that some core has been reworked
 to introduce the EEE.

v1: initial patch
v2: fixed some sparse issues (typos)
v3: erroneously sent the v2 renamed as v3
v4:
	o Fixed the return value of the stmmac_eee_init as suggested by D.Miller
	o Totally reviewed the ethtool support for EEE
	o Added a new internal parameter to tune the SW timer for TX LPI.
v5: do not change any eee setting in case of the stmmac_ethtool_op_set_eee fails
    (it has to return -EOPNOTSUPP in that case).

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h b/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h
index 23478bf..f90fcb5 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000.h
@@ -36,6 +36,7 @@
 
 #define GMAC_INT_STATUS		0x00000038	/* interrupt status register */
 enum dwmac1000_irq_status {
+	lpiis_irq = 0x400,
 	time_stamp_irq = 0x0200,
 	mmc_rx_csum_offload_irq = 0x0080,
 	mmc_tx_irq = 0x0040,
@@ -60,6 +61,25 @@
 	power_down = 0x00000001,
 };
 
+/* Energy Efficient Ethernet (EEE)
+ *
+ * LPI status, timer and control register offset
+ */
+#define LPI_CTRL_STATUS	0x0030
+#define LPI_TIMER_CTRL	0x0034
+
+/* LPI control and status defines */
+#define LPI_CTRL_STATUS_LPITXA	0x00080000	/* Enable LPI TX Automate */
+#define LPI_CTRL_STATUS_PLSEN	0x00040000	/* Enable PHY Link Status */
+#define LPI_CTRL_STATUS_PLS	0x00020000	/* PHY Link Status */
+#define LPI_CTRL_STATUS_LPIEN	0x00010000	/* LPI Enable */
+#define LPI_CTRL_STATUS_RLPIST	0x00000200	/* Receive LPI state */
+#define LPI_CTRL_STATUS_TLPIST	0x00000100	/* Transmit LPI state */
+#define LPI_CTRL_STATUS_RLPIEX	0x00000008	/* Receive LPI Exit */
+#define LPI_CTRL_STATUS_RLPIEN	0x00000004	/* Receive LPI Entry */
+#define LPI_CTRL_STATUS_TLPIEX	0x00000002	/* Transmit LPI Exit */
+#define LPI_CTRL_STATUS_TLPIEN	0x00000001	/* Transmit LPI Entry */
+
 /* GMAC HW ADDR regs */
 #define GMAC_ADDR_HIGH(reg)	(((reg > 15) ? 0x00000800 : 0x00000040) + \
 				(reg * 8))