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

[Daniel Hellstrom]

Module:    rtems
Branch:    master
Commit:    053b17ce8e3f710167e9ec3f44b37756cbdcbec0
Changeset: http://git.rtems.org/rtems/commit/?id=053b17ce8e3f710167e9ec3f44b37756cbdcbec0

Author:    Daniel Hellstrom <daniel at gaisler.com>
Date:      Fri Apr 26 15:18:11 2019 +0200

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/include/grlib/greth.h    |  1 +
 bsps/shared/grlib/net/greth.c | 22 +++++++++++++++-------
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/bsps/include/grlib/greth.h b/bsps/include/grlib/greth.h
index 1c42c99..e7970a7 100644
--- a/bsps/include/grlib/greth.h
+++ b/bsps/include/grlib/greth.h
@@ -100,6 +100,7 @@ typedef struct _greth_regs {
 #define GRETH_STATUS_TXIRQ      0x00000008 /* Transmit Error IRQ */
 #define GRETH_STATUS_RXAHBERR   0x00000010 /* Receiver AHB Error */
 #define GRETH_STATUS_TXAHBERR   0x00000020 /* Transmitter AHB Error */
+#define GRETH_STATUS_NRD        0x0f000000 /* Number of descriptors */
 
 /* MDIO Control  */
 #define GRETH_MDIO_WRITE        0x00000001 /* MDIO Write */
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);