MIPS: Octeon: Add Octeon III CN7xxx interface detection

Add basic CN7XXX interface detection.

This allows the kernel to boot with ethernet working as it initializes
the ethernet ports with SGMII instead of defaulting to RGMII routines.

Tested on the utm8 from Rhino Labs with a CN7130.

Signed-off-by: Zubair Lutfullah Kakakhel <[e-mail]>
Acked-by: David Daney <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Patchwork: https://patchwork.linux-mips.org/patch/12376/
Signed-off-by: Ralf Baechle <[e-mail]>

arch/mips/cavium-octeon/executive/cvmx-helper.c

···
 		return 9;
 	if (OCTEON_IS_MODEL(OCTEON_CN56XX) || OCTEON_IS_MODEL(OCTEON_CN52XX))
 		return 4;
+	if (OCTEON_IS_MODEL(OCTEON_CN7XXX))
+		return 5;
 	else
 		return 3;
 }
···
 }
 
 /**
+ * @INTERNAL
+ * Return interface mode for CN7XXX.
+ */
+static cvmx_helper_interface_mode_t __cvmx_get_mode_cn7xxx(int interface)
+{
+	union cvmx_gmxx_inf_mode mode;
+
+	mode.u64 = cvmx_read_csr(CVMX_GMXX_INF_MODE(interface));
+
+	switch (interface) {
+	case 0:
+	case 1:
+		switch (mode.cn68xx.mode) {
+		case 0:
+			return CVMX_HELPER_INTERFACE_MODE_DISABLED;
+		case 1:
+		case 2:
+			return CVMX_HELPER_INTERFACE_MODE_SGMII;
+		case 3:
+			return CVMX_HELPER_INTERFACE_MODE_XAUI;
+		default:
+			return CVMX_HELPER_INTERFACE_MODE_SGMII;
+		}
+	case 2:
+		return CVMX_HELPER_INTERFACE_MODE_NPI;
+	case 3:
+		return CVMX_HELPER_INTERFACE_MODE_LOOP;
+	case 4:
+		return CVMX_HELPER_INTERFACE_MODE_RGMII;
+	default:
+		return CVMX_HELPER_INTERFACE_MODE_DISABLED;
+	}
+}
+
+/**
  * Get the operating mode of an interface. Depending on the Octeon
  * chip and configuration, this function returns an enumeration
  * of the type of packet I/O supported by an interface.
···
 	if (interface < 0 ||
 	    interface >= cvmx_helper_get_number_of_interfaces())
 		return CVMX_HELPER_INTERFACE_MODE_DISABLED;
+
+	/*
+	 * OCTEON III models
+	 */
+	if (OCTEON_IS_MODEL(OCTEON_CN7XXX))
+		return __cvmx_get_mode_cn7xxx(interface);
 
 	/*
 	 * Octeon II models