[Qemu-devel] [PATCH 06/11] usb: Convert usb_packet_{map, unmap} to universal DMA helpers

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

From: David Gibson <david@gibson.dropbear.id.au>

The USB UHCI and EHCI drivers were converted some time ago to use the
pci_dma_*() helper functions.  However, this conversion was not complete
because in some places both these drivers do DMA via the usb_packet_map()
function in usb-libhw.c.  That function directly used
cpu_physical_memory_map().

Now that the sglist code uses DMA wrappers properly, we can convert the
functions in usb-libhw.c, thus conpleting the conversion of UHCI and EHCI
to use the DMA wrappers.

Note that usb_packet_map() invokes dma_memory_map() with a NULL invalidate
callback function.  When IOMMU support is added, this will mean that
usb_packet_map() and the corresponding usb_packet_unmap() must be called in
close proximity without dropping the qemu device lock - otherwise the guest
might invalidate IOMMU mappings while they are still in use by the device
code.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 hw/usb.h          |    2 +-
 hw/usb/hcd-ehci.c |    4 ++--
 hw/usb/hcd-uhci.c |    2 +-
 hw/usb/libhw.c    |   21 +++++++++++----------
 4 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/hw/usb.h b/hw/usb.h
index 2a56fe5..a5623d3 100644
--- a/hw/usb.h
+++ b/hw/usb.h
@@ -345,7 +345,7 @@ void usb_packet_check_state(USBPacket *p, USBPacketState expected);
 void usb_packet_setup(USBPacket *p, int pid, USBEndpoint *ep);
 void usb_packet_addbuf(USBPacket *p, void *ptr, size_t len);
 int usb_packet_map(USBPacket *p, QEMUSGList *sgl);
-void usb_packet_unmap(USBPacket *p);
+void usb_packet_unmap(USBPacket *p, QEMUSGList *sgl);
 void usb_packet_copy(USBPacket *p, void *ptr, size_t bytes);
 void usb_packet_skip(USBPacket *p, size_t bytes);
 void usb_packet_cleanup(USBPacket *p);
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 5298204..81bbc54 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -1422,8 +1422,8 @@ static void ehci_execute_complete(EHCIQueue *q)
         set_field(&q->qh.token, p->tbytes, QTD_TOKEN_TBYTES);
     }
     ehci_finish_transfer(q, p->usb_status);
+    usb_packet_unmap(&p->packet, &p->sgl);
     qemu_sglist_destroy(&p->sgl);
-    usb_packet_unmap(&p->packet);
 
     q->qh.token ^= QTD_TOKEN_DTOGGLE;
     q->qh.token &= ~QTD_TOKEN_ACTIVE;
@@ -1547,7 +1547,7 @@ static int ehci_process_itd(EHCIState *ehci,
                 usb_packet_map(&ehci->ipacket, &ehci->isgl);
                 ret = usb_handle_packet(dev, &ehci->ipacket);
                 assert(ret != USB_RET_ASYNC);
-                usb_packet_unmap(&ehci->ipacket);
+                usb_packet_unmap(&ehci->ipacket, &ehci->isgl);
             } else {
                 DPRINTF("ISOCH: attempt to addess non-iso endpoint\n");
                 ret = USB_RET_NAK;
diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
index 9871e24..86888ce 100644
--- a/hw/usb/hcd-uhci.c
+++ b/hw/usb/hcd-uhci.c
@@ -871,7 +871,7 @@ static int uhci_handle_td(UHCIState *s, uint32_t addr, UHCI_TD *td,
 
 done:
     len = uhci_complete_td(s, td, async, int_mask);
-    usb_packet_unmap(&async->packet);
+    usb_packet_unmap(&async->packet, &async->sgl);
     uhci_async_free(async);
     return len;
 }
diff --git a/hw/usb/libhw.c b/hw/usb/libhw.c
index 2462351..c0de30e 100644
--- a/hw/usb/libhw.c
+++ b/hw/usb/libhw.c
@@ -26,15 +26,15 @@
 
 int usb_packet_map(USBPacket *p, QEMUSGList *sgl)
 {
-    int is_write = (p->pid == USB_TOKEN_IN);
-    target_phys_addr_t len;
+    DMADirection dir = (p->pid == USB_TOKEN_IN) ?
+        DMA_DIRECTION_FROM_DEVICE : DMA_DIRECTION_TO_DEVICE;
+    dma_addr_t len;
     void *mem;
     int i;
 
     for (i = 0; i < sgl->nsg; i++) {
         len = sgl->sg[i].len;
-        mem = cpu_physical_memory_map(sgl->sg[i].base, &len,
-                                      is_write);
+        mem = dma_memory_map(sgl->dma, sgl->sg[i].base, &len, dir);
         if (!mem) {
             goto err;
         }
@@ -46,18 +46,19 @@ int usb_packet_map(USBPacket *p, QEMUSGList *sgl)
     return 0;
 
 err:
-    usb_packet_unmap(p);
+    usb_packet_unmap(p, sgl);
     return -1;
 }
 
-void usb_packet_unmap(USBPacket *p)
+void usb_packet_unmap(USBPacket *p, QEMUSGList *sgl)
 {
-    int is_write = (p->pid == USB_TOKEN_IN);
+    DMADirection dir = (p->pid == USB_TOKEN_IN) ?
+        DMA_DIRECTION_FROM_DEVICE : DMA_DIRECTION_TO_DEVICE;
     int i;
 
     for (i = 0; i < p->iov.niov; i++) {
-        cpu_physical_memory_unmap(p->iov.iov[i].iov_base,
-                                  p->iov.iov[i].iov_len, is_write,
-                                  p->iov.iov[i].iov_len);
+        dma_memory_unmap(sgl->dma, p->iov.iov[i].iov_base,
+                         p->iov.iov[i].iov_len, dir,
+                         p->iov.iov[i].iov_len);
     }
 }
-- 
1.7.9.5