firewire: fw-ohci: TSB43AB22/A dualbuffer workaround

Isochronous reception in dualbuffer mode is reportedly broken with
TI TSB43AB22A on x86-64.  Descriptor addresses above 2G have been
determined as the trigger:
https://bugzilla.redhat.com/show_bug.cgi?id=435550

Two fixes are possible:
  - pci_set_consistent_dma_mask(pdev, DMA_31BIT_MASK);
    at least when IR descriptors are allocated, or
  - simply don't use dualbuffer.
This fix implements the latter workaround.

But we keep using dualbuffer on x86-32 which won't give us highmen (and
thus physical addresses outside the 31bit range) in coherent DMA memory
allocations.  Right now we could for example also whitelist PPC32, but
DMA mapping implementation details are expected to change there.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>

1 files changed, 24 insertions, 13 deletions

diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index 333b12544dd..a4eff32621b 100644
--- a/drivers/firewire/fw-ohci.c
+++ b/drivers/firewire/fw-ohci.c
@@ -171,7 +171,6 @@ struct iso_context {
 struct fw_ohci {
         struct fw_card card;
 
-        u32 version;
         __iomem char *registers;
         dma_addr_t self_id_bus;
         __le32 *self_id_cpu;
@@ -180,6 +179,8 @@ struct fw_ohci {
         int generation;
         int request_generation; /* for timestamping incoming requests */
         u32 bus_seconds;
+
+        bool use_dualbuffer;
         bool old_uninorth;
         bool bus_reset_packet_quirk;
 
@@ -1885,7 +1886,7 @@ ohci_allocate_iso_context(struct fw_card *card, int type, size_t header_size)
         } else {
                 mask = &ohci->ir_context_mask;
                 list = ohci->ir_context_list;
-                if (ohci->version >= OHCI_VERSION_1_1)
+                if (ohci->use_dualbuffer)
                         callback = handle_ir_dualbuffer_packet;
                 else
                         callback = handle_ir_packet_per_buffer;
@@ -1949,7 +1950,7 @@ static int ohci_start_iso(struct fw_iso_context *base,
         } else {
                 index = ctx - ohci->ir_context_list;
                 control = IR_CONTEXT_ISOCH_HEADER;
-                if (ohci->version >= OHCI_VERSION_1_1)
+                if (ohci->use_dualbuffer)
                         control |= IR_CONTEXT_DUAL_BUFFER_MODE;
                 match = (tags << 28) | (sync << 8) | ctx->base.channel;
                 if (cycle >= 0) {
@@ -2279,7 +2280,7 @@ ohci_queue_iso(struct fw_iso_context *base,
         spin_lock_irqsave(&ctx->context.ohci->lock, flags);
         if (base->type == FW_ISO_CONTEXT_TRANSMIT)
                 retval = ohci_queue_iso_transmit(base, packet, buffer, payload);
-        else if (ctx->context.ohci->version >= OHCI_VERSION_1_1)
+        else if (ctx->context.ohci->use_dualbuffer)
                 retval = ohci_queue_iso_receive_dualbuffer(base, packet,
                                                          buffer, payload);
         else
@@ -2341,7 +2342,7 @@ static int __devinit
 pci_probe(struct pci_dev *dev, const struct pci_device_id *ent)
 {
         struct fw_ohci *ohci;
-        u32 bus_options, max_receive, link_speed;
+        u32 bus_options, max_receive, link_speed, version;
         u64 guid;
         int err;
         size_t size;
@@ -2366,12 +2367,6 @@ pci_probe(struct pci_dev *dev, const struct pci_device_id *ent)
         pci_write_config_dword(dev, OHCI1394_PCI_HCI_Control, 0);
         pci_set_drvdata(dev, ohci);
 
-#if defined(CONFIG_PPC_PMAC) && defined(CONFIG_PPC32)
-        ohci->old_uninorth = dev->vendor == PCI_VENDOR_ID_APPLE &&
-                             dev->device == PCI_DEVICE_ID_APPLE_UNI_N_FW;
-#endif
-        ohci->bus_reset_packet_quirk = dev->vendor == PCI_VENDOR_ID_TI;
-
         spin_lock_init(&ohci->lock);
 
         tasklet_init(&ohci->bus_reset_tasklet,
@@ -2390,6 +2385,23 @@ pci_probe(struct pci_dev *dev, const struct pci_device_id *ent)
                 goto fail_iomem;
         }
 
+        version = reg_read(ohci, OHCI1394_Version) & 0x00ff00ff;
+        ohci->use_dualbuffer = version >= OHCI_VERSION_1_1;
+
+/* x86-32 currently doesn't use highmem for dma_alloc_coherent */
+#if !defined(CONFIG_X86_32)
+        /* dual-buffer mode is broken with descriptor addresses above 2G */
+        if (dev->vendor == PCI_VENDOR_ID_TI &&
+            dev->device == PCI_DEVICE_ID_TI_TSB43AB22)
+                ohci->use_dualbuffer = false;
+#endif
+
+#if defined(CONFIG_PPC_PMAC) && defined(CONFIG_PPC32)
+        ohci->old_uninorth = dev->vendor == PCI_VENDOR_ID_APPLE &&
+                             dev->device == PCI_DEVICE_ID_APPLE_UNI_N_FW;
+#endif
+        ohci->bus_reset_packet_quirk = dev->vendor == PCI_VENDOR_ID_TI;
+
         ar_context_init(&ohci->ar_request_ctx, ohci,
                         OHCI1394_AsReqRcvContextControlSet);
 
@@ -2441,9 +2453,8 @@ pci_probe(struct pci_dev *dev, const struct pci_device_id *ent)
         if (err < 0)
                 goto fail_self_id;
 
-        ohci->version = reg_read(ohci, OHCI1394_Version) & 0x00ff00ff;
         fw_notify("Added fw-ohci device %s, OHCI version %x.%x\n",
-                  dev->dev.bus_id, ohci->version >> 16, ohci->version & 0xff);
+                  dev->dev.bus_id, version >> 16, version & 0xff);
         return 0;
 
  fail_self_id: