[rtems-net-legacy commit] leon,greth: added support for variable sized descriptor table sizes

[Vijay Kumar Banerjee]

Module:    rtems-net-legacy
Branch:    main
Commit:    52169bd2981e5a8a0535b0c3cf8e5868aa393b50
Changeset: http://git.rtems.org/rtems-net-legacy/commit/?id=52169bd2981e5a8a0535b0c3cf8e5868aa393b50

Author:    Daniel Hellstrom <daniel at gaisler.com>
Date:      Tue Mar 30 09:46:56 2021 -0600

leon,greth: added support for variable sized descriptor table sizes

    The descriptor table size is equal to its alignment and set when
    configuring the HW IP through VHDL generics. This SW patch simply
    probes the HW how large the RX/TX descriptor tables are and adjusts
    accordingly.

    The number of descriptors actual used are controlled by other
    settings (rxDescs and txDescs) controlled by the user.

---

 bsps/shared/grlib/net/greth.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/bsps/shared/grlib/net/greth.c b/bsps/shared/grlib/net/greth.c
index 8b19b48..84efcd7 100644
--- a/bsps/shared/grlib/net/greth.c
+++ b/bsps/shared/grlib/net/greth.c
@@ -187,6 +187,7 @@ struct greth_softc
    unsigned int advmodes; /* advertise ethernet speed modes. 0 = all modes. */
    struct timespec auto_neg_time;
    int mc_available;
+   int num_descs;
 
    /*
     * Statistics
@@ -423,7 +424,7 @@ greth_initialize_hardware (struct greth_softc *sc)
     int tmp2;
     struct timespec tstart, tnow;
     greth_regs *regs;
-    unsigned int advmodes, speed;
+    unsigned int advmodes, speed, tabsize;
 
     regs = sc->regs;
 
@@ -617,8 +618,9 @@ auto_neg_done:
     /* Initialize rx/tx descriptor table pointers. Due to alignment we 
      * always allocate maximum table size.
      */
-    sc->txdesc = (greth_rxtxdesc *) almalloc(0x800, 0x400);
-    sc->rxdesc = (greth_rxtxdesc *) &sc->txdesc[128];
+    tabsize = sc->num_descs * 8;
+    sc->txdesc = (greth_rxtxdesc *) almalloc(tabsize * 2, tabsize);
+    sc->rxdesc = (greth_rxtxdesc *) (tabsize + (void *)sc->txdesc);
     sc->tx_ptr = 0;
     sc->tx_dptr = 0;
     sc->tx_cnt = 0;
@@ -632,8 +634,8 @@ auto_neg_done:
         CPUMEM_TO_DMA,
         (void *)sc->txdesc,
         (void **)&sc->txdesc_remote,
-        0x800);
-    sc->rxdesc_remote = sc->txdesc_remote + 0x400;
+        tabsize * 2);
+    sc->rxdesc_remote = sc->txdesc_remote + tabsize;
     regs->txdesc = (int) sc->txdesc_remote;
     regs->rxdesc = (int) sc->rxdesc_remote;
 
@@ -1555,6 +1557,7 @@ int greth_device_init(struct greth_softc *sc)
     struct ambapp_core *pnpinfo;
     union drvmgr_key_value *value;
     unsigned int speed;
+    int i, nrd;
 
     /* Get device information from AMBA PnP information */
     ambadev = (struct amba_dev_info *)sc->dev->businfo;
@@ -1608,12 +1611,17 @@ int greth_device_init(struct greth_softc *sc)
     sc->rxbufs = 32;
     sc->phyaddr = -1;
 
+    /* Probe the number of descriptors available the */
+    nrd = (sc->regs->status & GRETH_STATUS_NRD) >> 24;
+    for (sc->num_descs = 128, i = 0; i < nrd; i++)
+        sc->num_descs = sc->num_descs * 2;
+
     value = drvmgr_dev_key_get(sc->dev, "txDescs", DRVMGR_KT_INT);
-    if ( value && (value->i <= 128) )
+    if ( value && (value->i <= sc->num_descs) )
         sc->txbufs = value->i;
 
     value = drvmgr_dev_key_get(sc->dev, "rxDescs", DRVMGR_KT_INT);
-    if ( value && (value->i <= 128) )
+    if ( value && (value->i <= sc->num_descs) )
         sc->rxbufs = value->i;
 
     value = drvmgr_dev_key_get(sc->dev, "phyAdr", DRVMGR_KT_INT);