Use config register to determine if 64-bit DMA is available.

Suggested by and OK kettenis@

diff --git a/sys/dev/fdt/if_cad.c b/sys/dev/fdt/if_cad.c
index 846e5f8..f6c488f 100644 (file)
--- a/sys/dev/fdt/if_cad.c
+++ b/sys/dev/fdt/if_cad.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_cad.c,v 1.5 2021/06/27 01:58:51 jsg Exp $  */
+/*     $OpenBSD: if_cad.c,v 1.6 2021/06/27 04:32:31 visa Exp $ */
 
 /*
  * Copyright (c) 2021 Visa Hankala
@@ -126,6 +126,8 @@
 #define GEM_LADDRH(i)                  (0x008c + (i) * 8)
 #define GEM_LADDRNUM                   4
 #define GEM_MID                                0x00fc
+#define  GEM_MID_VERSION_MASK                  (0xfff << 16)
+#define  GEM_MID_VERSION_SHIFT                 16
 #define GEM_OCTTXL                     0x0100
 #define GEM_OCTTXH                     0x0104
 #define GEM_TXCNT                      0x0108
@@ -169,6 +171,8 @@
 #define GEM_RXIPCCNT                   0x01a8
 #define GEM_RXTCPCCNT                  0x01ac
 #define GEM_RXUDPCCNT                  0x01b0
+#define GEM_CFG6                       0x0294
+#define  GEM_CFG6_DMA64                                (1 << 23)
 #define GEM_TXQBASEHI                  0x04c8
 #define GEM_RXQBASEHI                  0x04d4
 
@@ -365,6 +369,7 @@ cad_attach(struct device *parent, struct device *self, void *aux)
        struct cad_softc *sc = (struct cad_softc *)self;
        struct ifnet *ifp = &sc->sc_ac.ac_if;
        uint32_t hi, lo;
+       uint32_t rev, ver;
        unsigned int i;
        int node, phy;
 
@@ -417,9 +422,12 @@ cad_attach(struct device *parent, struct device *self, void *aux)
                }
        }
 
+       rev = HREAD4(sc, GEM_MID);
+       ver = (rev & GEM_MID_VERSION_MASK) >> GEM_MID_VERSION_SHIFT;
+
        sc->sc_descsize = sizeof(struct cad_desc32);
-       if (OF_is_compatible(faa->fa_node, "sifive,fu540-c000-gem") ||
-           OF_is_compatible(faa->fa_node, "sifive,fu740-c000-gem")) {
+       /* Register CFG6 is not present on Zynq-7000 / GEM version 0x2. */
+       if (ver >= 0x7 && (HREAD4(sc, GEM_CFG6) & GEM_CFG6_DMA64)) {
                sc->sc_descsize = sizeof(struct cad_desc64);
                sc->sc_dma64 = 1;
        }
@@ -461,7 +469,7 @@ cad_attach(struct device *parent, struct device *self, void *aux)
                    IFCAP_CSUM_TCPv6 | IFCAP_CSUM_UDPv6;
        }
 
-       printf(": rev 0x%x, address %s\n", HREAD4(sc, GEM_MID),
+       printf(": rev 0x%x, address %s\n", rev,
            ether_sprintf(sc->sc_ac.ac_enaddr));
 
        sc->sc_mii.mii_ifp = ifp;