Re: [PATCH] r8169: default to 64-bit DMA on systems without memory below 4 GB

[Francois Romieu]

Francois Romieu <rom...@fr.zoreil.com> :
> Ard Biesheuvel <ard.biesheu...@linaro.org> :
> > On 12 May 2016 at 16:09, Francois Romieu <rom...@fr.zoreil.com> wrote:
> [...]
> > By resurrecting 353176888386, I mean the patch that changes the
> > default for PCI express devices, so I think we are in agreement here ?
> 
> Almost 353176888386: please modify it so that there's no change of
> behavior for mac_version < RTL_GIGA_MAC_VER_18.
> 
> It will avoid a bit more than the plain old PCI chipsets, including the
> one that caused 353176888386 reversal as well as a few one that I don't
> feel confortable with due to their vicinity with the original 8169.

The patch below may be of use before refreshing 353176888386:

Btw I have to find a way to force descriptor ring allocation above 4G
because none of my testing has exercized it so far but my tax
paperwork can't wait.

Good luck.

diff --git a/drivers/net/ethernet/realtek/r8169.c 
b/drivers/net/ethernet/realtek/r8169.c
index 94f08f1..ac23240 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -8224,20 +8224,6 @@ static int rtl_init_one(struct pci_dev *pdev, const 
struct pci_device_id *ent)
                goto err_out_mwi_2;
        }
 
-       tp->cp_cmd = 0;
-
-       if ((sizeof(dma_addr_t) > 4) &&
-           !pci_set_dma_mask(pdev, DMA_BIT_MASK(64)) && use_dac) {
-               tp->cp_cmd |= PCIDAC;
-               dev->features |= NETIF_F_HIGHDMA;
-       } else {
-               rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
-               if (rc < 0) {
-                       netif_err(tp, probe, dev, "DMA configuration failed\n");
-                       goto err_out_free_res_3;
-               }
-       }
-
        /* ioremap MMIO region */
        ioaddr = ioremap(pci_resource_start(pdev, region), R8169_REGS_SIZE);
        if (!ioaddr) {
@@ -8253,6 +8239,20 @@ static int rtl_init_one(struct pci_dev *pdev, const 
struct pci_device_id *ent)
        /* Identify chip attached to board */
        rtl8169_get_mac_version(tp, dev, cfg->default_ver);
 
+       tp->cp_cmd = 0;
+
+       if ((sizeof(dma_addr_t) > 4) &&
+           !pci_set_dma_mask(pdev, DMA_BIT_MASK(64)) && use_dac) {
+               tp->cp_cmd |= PCIDAC;
+               dev->features |= NETIF_F_HIGHDMA;
+       } else {
+               rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+               if (rc < 0) {
+                       netif_err(tp, probe, dev, "DMA configuration failed\n");
+                       goto err_out_unmap_4;
+               }
+       }
+
        rtl_init_rxcfg(tp);
 
        rtl_irq_disable(tp);
@@ -8412,12 +8412,12 @@ static int rtl_init_one(struct pci_dev *pdev, const 
struct pci_device_id *ent)
                                           &tp->counters_phys_addr, GFP_KERNEL);
        if (!tp->counters) {
                rc = -ENOMEM;
-               goto err_out_msi_4;
+               goto err_out_msi_5;
        }
 
        rc = register_netdev(dev);
        if (rc < 0)
-               goto err_out_cnt_5;
+               goto err_out_cnt_6;
 
        pci_set_drvdata(pdev, dev);
 
@@ -8451,12 +8451,13 @@ static int rtl_init_one(struct pci_dev *pdev, const 
struct pci_device_id *ent)
 out:
        return rc;
 
-err_out_cnt_5:
+err_out_cnt_6:
        dma_free_coherent(&pdev->dev, sizeof(*tp->counters), tp->counters,
                          tp->counters_phys_addr);
-err_out_msi_4:
+err_out_msi_5:
        netif_napi_del(&tp->napi);
        rtl_disable_msi(pdev, tp);
+err_out_unmap_4:
        iounmap(ioaddr);
 err_out_free_res_3:
        pci_release_regions(pdev);