Fix xae(4) driver attachement on the Government Furnished Equipment (GFE)

riscv cores.

GFE cores come with standard DTS file that lacks standard 'dmas ='
property, which means xae(4) could not find a DMA controller to use.

The 'dmas' property could not be added to the DTS file because the
ethernet controller and DMA engine parts in Linux are implemented
in a single driver.

Instead of 'dmas' property the standard Xilinx 'axistream-connected'
property is provided, so fallback to use it instead.

Suggested by:	James Clarke <jrtc27@jrtc27.com>
Reviewed by:	James Clarke <jrtc27@jrtc27.com>
Sponsored by:	DARPA, AFRL

sys/dev/xdma/xdma.c

@@ -510,6 +510,24 @@ xdma_ofw_get(device_t dev, const char *prop)
 }
 #endif
 
+/*
+ * Allocate xdma controller.
+ */
+xdma_controller_t *
+xdma_get(device_t dev, device_t dma_dev)
+{
+	xdma_controller_t *xdma;
+
+	xdma = malloc(sizeof(struct xdma_controller),
+	    M_XDMA, M_WAITOK | M_ZERO);
+	xdma->dev = dev;
+	xdma->dma_dev = dma_dev;
+
+	TAILQ_INIT(&xdma->channels);
+
+	return (xdma);
+}
+
 /*
  * Free xDMA controller object.
  */

sys/dev/xdma/xdma.h

@@ -231,6 +231,7 @@ static MALLOC_DEFINE(M_XDMA, "xdma", "xDMA framework");
 
 /* xDMA controller ops */
 xdma_controller_t *xdma_ofw_get(device_t dev, const char *prop);
+xdma_controller_t *xdma_get(device_t dev, device_t dma_dev);
 int xdma_put(xdma_controller_t *xdma);
 vmem_t * xdma_get_memory(device_t dev);
 void xdma_put_memory(vmem_t *vmem);

sys/dev/xilinx/axidma.c

@@ -61,6 +61,15 @@ __FBSDID("$FreeBSD$");
 
 #include "xdma_if.h"
 
+#define	READ4(_sc, _reg)	\
+	bus_space_read_4(_sc->bst, _sc->bsh, _reg)
+#define	WRITE4(_sc, _reg, _val)	\
+	bus_space_write_4(_sc->bst, _sc->bsh, _reg, _val)
+#define	READ8(_sc, _reg)	\
+	bus_space_read_8(_sc->bst, _sc->bsh, _reg)
+#define	WRITE8(_sc, _reg, _val)	\
+	bus_space_write_8(_sc->bst, _sc->bsh, _reg, _val)
+
 #define AXIDMA_DEBUG
 #undef AXIDMA_DEBUG
 
@@ -70,17 +79,8 @@ __FBSDID("$FreeBSD$");
 #define dprintf(fmt, ...)
 #endif
 
-#define	AXIDMA_NCHANNELS	2
-#define	AXIDMA_DESCS_NUM	512
-#define	AXIDMA_TX_CHAN		0
-#define	AXIDMA_RX_CHAN		1
-
 extern struct bus_space memmap_bus;
 
-struct axidma_fdt_data {
-	int id;
-};
-
 struct axidma_channel {
 	struct axidma_softc	*sc;
 	xdma_channel_t		*xchan;

sys/dev/xilinx/axidma.h

@@ -60,14 +60,10 @@
 #define	AXI_TAILDESC_MSB(n)	(0x14 + 0x30 * (n)) /* Tail Descriptor Pointer. Upper 32 bits of address. */
 #define	AXI_SG_CTL		0x2C /* Scatter/Gather User and Cache */
 
-#define	READ4(_sc, _reg)	\
-	bus_space_read_4(_sc->bst, _sc->bsh, _reg)
-#define	WRITE4(_sc, _reg, _val)	\
-	bus_space_write_4(_sc->bst, _sc->bsh, _reg, _val)
-#define	READ8(_sc, _reg)	\
-	bus_space_read_8(_sc->bst, _sc->bsh, _reg)
-#define	WRITE8(_sc, _reg, _val)	\
-	bus_space_write_8(_sc->bst, _sc->bsh, _reg, _val)
+#define	AXIDMA_NCHANNELS	2
+#define	AXIDMA_DESCS_NUM	512
+#define	AXIDMA_TX_CHAN		0
+#define	AXIDMA_RX_CHAN		1
 
 struct axidma_desc {
 	uint32_t next;
@@ -93,4 +89,8 @@ struct axidma_desc {
 	uint32_t reserved[3];
 };
 
+struct axidma_fdt_data {
+	int id;
+};
+
 #endif /* !_DEV_XILINX_AXIDMA_H_ */

sys/dev/xilinx/if_xae.c

@@ -64,6 +64,8 @@ __FBSDID("$FreeBSD$");
 #include <dev/xilinx/if_xaereg.h>
 #include <dev/xilinx/if_xaevar.h>
 
+#include <dev/xilinx/axidma.h>
+
 #include "miibus_if.h"
 
 #define	READ4(_sc, _reg) \
@@ -774,6 +776,68 @@ xae_phy_fixup(struct xae_softc *sc)
 	} while ((PHY1_RD(sc, MII_BMSR) & BMSR_ACOMP) == 0);
 }
 
+static int
+get_xdma_std(struct xae_softc *sc)
+{
+
+	sc->xdma_tx = xdma_ofw_get(sc->dev, "tx");
+	if (sc->xdma_tx == NULL)
+		return (ENXIO);
+
+	sc->xdma_rx = xdma_ofw_get(sc->dev, "rx");
+	if (sc->xdma_rx == NULL) {
+		xdma_put(sc->xdma_tx);
+		return (ENXIO);
+	}
+
+	return (0);
+}
+
+static int
+get_xdma_axistream(struct xae_softc *sc)
+{
+	struct axidma_fdt_data *data;
+	device_t dma_dev;
+	phandle_t node;
+	pcell_t prop;
+	size_t len;
+
+	node = ofw_bus_get_node(sc->dev);
+	len = OF_getencprop(node, "axistream-connected", &prop, sizeof(prop));
+	if (len != sizeof(prop)) {
+		device_printf(sc->dev,
+		    "%s: Couldn't get axistream-connected prop.\n", __func__);
+		return (ENXIO);
+	}
+	dma_dev = OF_device_from_xref(prop);
+	if (dma_dev == NULL) {
+		device_printf(sc->dev, "Could not get DMA device by xref.\n");
+		return (ENXIO);
+	}
+
+	sc->xdma_tx = xdma_get(sc->dev, dma_dev);
+	if (sc->xdma_tx == NULL) {
+		device_printf(sc->dev, "Could not find DMA controller.\n");
+		return (ENXIO);
+	}
+	data = malloc(sizeof(struct axidma_fdt_data),
+	    M_DEVBUF, (M_WAITOK | M_ZERO));
+	data->id = AXIDMA_TX_CHAN;
+	sc->xdma_tx->data = data;
+
+	sc->xdma_rx = xdma_get(sc->dev, dma_dev);
+	if (sc->xdma_rx == NULL) {
+		device_printf(sc->dev, "Could not find DMA controller.\n");
+		return (ENXIO);
+	}
+	data = malloc(sizeof(struct axidma_fdt_data),
+	    M_DEVBUF, (M_WAITOK | M_ZERO));
+	data->id = AXIDMA_RX_CHAN;
+	sc->xdma_rx->data = data;
+
+	return (0);
+}
+
 static int
 setup_xdma(struct xae_softc *sc)
 {
@@ -784,15 +848,16 @@ setup_xdma(struct xae_softc *sc)
 	dev = sc->dev;
 
 	/* Get xDMA controller */   
-	sc->xdma_tx = xdma_ofw_get(sc->dev, "tx");
-	if (sc->xdma_tx == NULL) {
-		device_printf(dev, "Could not find DMA controller.\n");
-		return (ENXIO);
+	error = get_xdma_std(sc);
+
+	if (error) {
+		device_printf(sc->dev,
+		    "Fallback to axistream-connected property\n");
+		error = get_xdma_axistream(sc);
 	}
 
-	sc->xdma_rx = xdma_ofw_get(sc->dev, "rx");
-	if (sc->xdma_rx == NULL) {
-		device_printf(dev, "Could not find DMA controller.\n");
+	if (error) {
+		device_printf(dev, "Could not find xDMA controllers.\n");
 		return (ENXIO);
 	}