sun/cassini: Use dma_set_mask_and_coherent() and simplify code

Use dma_set_mask_and_coherent() instead of unrolling it with some
dma_set_mask()+dma_set_coherent_mask().

Moreover, as stated in [1], dma_set_mask() with a 64-bit mask will never
fail if dev->dma_mask is non-NULL.
So, if it fails, the 32 bits case will also fail for the same reason.

That said, 'pci_using_dac' can only be 1 after a successful
dma_set_mask_and_coherent().

Simplify code and remove some dead code accordingly.

[1]: https://lkml.org/lkml/2021/6/7/398

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c
index d2d4f47..dba9f12 100644 (file)
--- a/drivers/net/ethernet/sun/cassini.c
+++ b/drivers/net/ethernet/sun/cassini.c
@@ -4893,8 +4893,8 @@ static int cas_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
        unsigned long casreg_len;
        struct net_device *dev;
        struct cas *cp;
-       int i, err, pci_using_dac;
        u16 pci_cmd;
+       int i, err;
        u8 orig_cacheline_size = 0, cas_cacheline_size = 0;
 
        if (cas_version_printed++ == 0)
@@ -4965,23 +4965,10 @@ static int cas_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 
        /* Configure DMA attributes. */
-       if (!dma_set_mask(&pdev->dev, DMA_BIT_MASK(64))) {
-               pci_using_dac = 1;
-               err = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64));
-               if (err < 0) {
-                       dev_err(&pdev->dev, "Unable to obtain 64-bit DMA "
-                              "for consistent allocations\n");
-                       goto err_out_free_res;
-               }
-
-       } else {
-               err = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
-               if (err) {
-                       dev_err(&pdev->dev, "No usable DMA configuration, "
-                              "aborting\n");
-                       goto err_out_free_res;
-               }
-               pci_using_dac = 0;
+       err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+       if (err) {
+               dev_err(&pdev->dev, "No usable DMA configuration, aborting\n");
+               goto err_out_free_res;
        }
 
        casreg_len = pci_resource_len(pdev, 0);
@@ -5087,8 +5074,7 @@ static int cas_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
        if ((cp->cas_flags & CAS_FLAG_NO_HW_CSUM) == 0)
                dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG;
 
-       if (pci_using_dac)
-               dev->features |= NETIF_F_HIGHDMA;
+       dev->features |= NETIF_F_HIGHDMA;
 
        /* MTU range: 60 - varies or 9000 */
        dev->min_mtu = CAS_MIN_MTU;