gianfar: Implement workaround for eTSEC74 erratum

MPC8313ECE says:

"If MACCFG2[Huge Frame]=0 and the Ethernet controller receives frames
 which are larger than MAXFRM, the controller truncates the frames to
 length MAXFRM and marks RxBD[TR]=1 to indicate the error. The controller
 also erroneously marks RxBD[TR]=1 if the received frame length is MAXFRM
 or MAXFRM-1, even though those frames are not truncated.
 No truncation or truncation error occurs if MACCFG2[Huge Frame]=1."

There are two options to workaround the issue:

"1. Set MACCFG2[Huge Frame]=1, so no truncation occurs for invalid large
 frames. Software can determine if a frame is larger than MAXFRM by
 reading RxBD[LG] or RxBD[Data Length].

 2. Set MAXFRM to 1538 (0x602) instead of the default 1536 (0x600), so
 normal-length frames are not marked as truncated. Software can examine
 RxBD[Data Length] to determine if the frame was larger than MAXFRM-2."

This patch implements the first workaround option by setting HUGEFRAME
bit, and gfar_clean_rx_ring() already checks the RxBD[Data Length].

Signed-off-by: Anton Vorontsov <avorontsov@mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index c52f3712ecd3ca1e84656b1bde4053226bc57feb..cee8ae71473113087b138bf32e43ecec0e56e3bc 100644 (file)
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -85,6 +85,7 @@
 #include <linux/net_tstamp.h>
 
 #include <asm/io.h>
+#include <asm/reg.h>
 #include <asm/irq.h>
 #include <asm/uaccess.h>
 #include <linux/module.h>
@@ -928,6 +929,24 @@ static void gfar_init_filer_table(struct gfar_private *priv)
        }
 }
 
+static void gfar_detect_errata(struct gfar_private *priv)
+{
+       struct device *dev = &priv->ofdev->dev;
+       unsigned int pvr = mfspr(SPRN_PVR);
+       unsigned int svr = mfspr(SPRN_SVR);
+       unsigned int mod = (svr >> 16) & 0xfff6; /* w/o E suffix */
+       unsigned int rev = svr & 0xffff;
+
+       /* MPC8313 Rev 2.0 and higher; All MPC837x */
+       if ((pvr == 0x80850010 && mod == 0x80b0 && rev >= 0x0020) ||
+                       (pvr == 0x80861010 && (mod & 0xfff9) == 0x80c0))
+               priv->errata |= GFAR_ERRATA_74;
+
+       if (priv->errata)
+               dev_info(dev, "enabled errata workarounds, flags: 0x%x\n",
+                        priv->errata);
+}
+
 /* Set up the ethernet device structure, private data,
  * and anything else we need before we start */
 static int gfar_probe(struct of_device *ofdev,
@@ -960,6 +979,8 @@ static int gfar_probe(struct of_device *ofdev,
        dev_set_drvdata(&ofdev->dev, priv);
        regs = priv->gfargrp[0].regs;
 
+       gfar_detect_errata(priv);
+
        /* Stop the DMA engine now, in case it was running before */
        /* (The firmware could have used it, and left it running). */
        gfar_halt(dev);
@@ -974,7 +995,10 @@ static int gfar_probe(struct of_device *ofdev,
        gfar_write(&regs->maccfg1, tempval);
 
        /* Initialize MACCFG2. */
-       gfar_write(&regs->maccfg2, MACCFG2_INIT_SETTINGS);
+       tempval = MACCFG2_INIT_SETTINGS;
+       if (gfar_has_errata(priv, GFAR_ERRATA_74))
+               tempval |= MACCFG2_HUGEFRAME | MACCFG2_LENGTHCHECK;
+       gfar_write(&regs->maccfg2, tempval);
 
        /* Initialize ECNTRL */
        gfar_write(&regs->ecntrl, ECNTRL_INIT_SETTINGS);
@@ -2300,7 +2324,8 @@ static int gfar_change_mtu(struct net_device *dev, int new_mtu)
         * to allow huge frames, and to check the length */
        tempval = gfar_read(&regs->maccfg2);
 
-       if (priv->rx_buffer_size > DEFAULT_RX_BUFFER_SIZE)
+       if (priv->rx_buffer_size > DEFAULT_RX_BUFFER_SIZE ||
+                       gfar_has_errata(priv, GFAR_ERRATA_74))
                tempval |= (MACCFG2_HUGEFRAME | MACCFG2_LENGTHCHECK);
        else
                tempval &= ~(MACCFG2_HUGEFRAME | MACCFG2_LENGTHCHECK);

diff --git a/drivers/net/gianfar.h b/drivers/net/gianfar.h
index ac4a92e08c09b67b304d3084bffd9a494c80afb5..0a0483ce21d25e7173c8a7870dcbc934b98791a0 100644 (file)
--- a/drivers/net/gianfar.h
+++ b/drivers/net/gianfar.h
@@ -1025,6 +1025,10 @@ struct gfar_priv_grp {
        char int_name_er[GFAR_INT_NAME_MAX];
 };
 
+enum gfar_errata {
+       GFAR_ERRATA_74          = 0x01,
+};
+
 /* Struct stolen almost completely (and shamelessly) from the FCC enet source
  * (Ok, that's not so true anymore, but there is a family resemblence)
  * The GFAR buffer descriptors track the ring buffers.  The rx_bd_base
@@ -1049,6 +1053,7 @@ struct gfar_private {
        struct device_node *node;
        struct net_device *ndev;
        struct of_device *ofdev;
+       enum gfar_errata errata;
 
        struct gfar_priv_grp gfargrp[MAXGROUPS];
        struct gfar_priv_tx_q *tx_queue[MAX_TX_QS];
@@ -1111,6 +1116,12 @@ struct gfar_private {
 extern unsigned int ftp_rqfpr[MAX_FILER_IDX + 1];
 extern unsigned int ftp_rqfcr[MAX_FILER_IDX + 1];
 
+static inline int gfar_has_errata(struct gfar_private *priv,
+                                 enum gfar_errata err)
+{
+       return priv->errata & err;
+}
+
 static inline u32 gfar_read(volatile unsigned __iomem *addr)
 {
        u32 val;