Revert "net: qcom/emac: enforce DMA address restrictions"

This reverts commit df1ec1b9d0df57e96011f175418dc95b1af46821.

It turns out that memory allocated via dma_alloc_coherent is always
aligned to the size of the buffer, so there's no way the RRD and RFD
can ever be in separate 32-bit regions.

Signed-off-by: Timur Tabi <timur@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/qualcomm/emac/emac-mac.c b/drivers/net/ethernet/qualcomm/emac/emac-mac.c
index 0f5ece5..9cbb272 100644 (file)
--- a/drivers/net/ethernet/qualcomm/emac/emac-mac.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac-mac.c
@@ -734,11 +734,6 @@ static int emac_rx_descs_alloc(struct emac_adapter *adpt)
        rx_q->rrd.size = rx_q->rrd.count * (adpt->rrd_size * 4);
        rx_q->rfd.size = rx_q->rfd.count * (adpt->rfd_size * 4);
 
-       /* Check if the RRD and RFD are aligned properly, and if not, adjust. */
-       if (upper_32_bits(ring_header->dma_addr) !=
-           upper_32_bits(ring_header->dma_addr + ALIGN(rx_q->rrd.size, 8)))
-               ring_header->used = ALIGN(rx_q->rrd.size, 8);
-
        rx_q->rrd.dma_addr = ring_header->dma_addr + ring_header->used;
        rx_q->rrd.v_addr   = ring_header->v_addr + ring_header->used;
        ring_header->used += ALIGN(rx_q->rrd.size, 8);
@@ -772,18 +767,11 @@ int emac_mac_rx_tx_rings_alloc_all(struct emac_adapter *adpt)
 
        /* Ring DMA buffer. Each ring may need up to 8 bytes for alignment,
         * hence the additional padding bytes are allocated.
-        *
-        * Also double the memory allocated for the RRD so that we can
-        * re-align it if necessary.  The EMAC has a restriction that the
-        * upper 32 bits of the base addresses for the RFD and RRD rings
-        * must be the same.  It is extremely unlikely that this is not the
-        * case, since the rings are only a few KB in size.  However, we
-        * need to check for this anyway, and if the two rings are not
-        * compliant, then we re-align.
         */
-       ring_header->size = ALIGN(num_tx_descs * (adpt->tpd_size * 4), 8) +
-                           ALIGN(num_rx_descs * (adpt->rfd_size * 4), 8) +
-                           ALIGN(num_rx_descs * (adpt->rrd_size * 4), 8) * 2;
+       ring_header->size = num_tx_descs * (adpt->tpd_size * 4) +
+                           num_rx_descs * (adpt->rfd_size * 4) +
+                           num_rx_descs * (adpt->rrd_size * 4) +
+                           8 + 2 * 8; /* 8 byte per one Tx and two Rx rings */
 
        ring_header->used = 0;
        ring_header->v_addr = dma_zalloc_coherent(dev, ring_header->size,
@@ -792,23 +780,26 @@ int emac_mac_rx_tx_rings_alloc_all(struct emac_adapter *adpt)
        if (!ring_header->v_addr)
                return -ENOMEM;
 
-       ret = emac_rx_descs_alloc(adpt);
-       if (ret) {
-               netdev_err(adpt->netdev, "error: Rx Queue alloc failed\n");
-               goto err_alloc_rx;
-       }
+       ring_header->used = ALIGN(ring_header->dma_addr, 8) -
+                                                       ring_header->dma_addr;
 
        ret = emac_tx_q_desc_alloc(adpt, &adpt->tx_q);
        if (ret) {
-               netdev_err(adpt->netdev, "transmit queue allocation failed\n");
+               netdev_err(adpt->netdev, "error: Tx Queue alloc failed\n");
                goto err_alloc_tx;
        }
 
+       ret = emac_rx_descs_alloc(adpt);
+       if (ret) {
+               netdev_err(adpt->netdev, "error: Rx Queue alloc failed\n");
+               goto err_alloc_rx;
+       }
+
        return 0;
 
-err_alloc_tx:
-       emac_rx_q_bufs_free(adpt);
 err_alloc_rx:
+       emac_tx_q_bufs_free(adpt);
+err_alloc_tx:
        dma_free_coherent(dev, ring_header->size,
                          ring_header->v_addr, ring_header->dma_addr);