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firewire: ohci: 0 may be a valid DMA address

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I was told that there are obscure architectures with non-coherent DMA
which may DMA-map to bus address 0.  We shall not use 0 as a magic
number of uninitialized bus address variables.

The packet->payload_length > 0 test cannot be used either (except in
at_context_queue_packet) because local requests are not DMA-mapped
regardless of payload_length.  Hence add a state flag to struct
fw_packet.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This commit is contained in:
Stefan Richter 2009-10-14 20:40:10 +02:00
parent 5b189bf363
commit 19593ffdb6
3 changed files with 8 additions and 6 deletions
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4
drivers/firewire/core-transaction.c
View file

@ -226,7 +226,7 @@ static void fw_fill_request(struct fw_packet *packet, int tcode, int tlabel,
packet->speed = speed;
packet->generation = generation;
packet->ack = 0;
packet->payload_bus = 0;
packet->payload_mapped = false;
}
/**
@ -601,7 +601,7 @@ void fw_fill_response(struct fw_packet *response, u32 *request_header,
WARN(1, KERN_ERR "wrong tcode %d", tcode);
}
response->payload_bus = 0;
response->payload_mapped = false;
}
EXPORT_SYMBOL(fw_fill_response);

9
drivers/firewire/ohci.c
View file

@ -995,7 +995,8 @@ static int at_context_queue_packet(struct context *ctx,
packet->ack = RCODE_SEND_ERROR;
return -1;
}
packet->payload_bus = payload_bus;
packet->payload_bus = payload_bus;
packet->payload_mapped = true;
d[2].req_count = cpu_to_le16(packet->payload_length);
d[2].data_address = cpu_to_le32(payload_bus);
@ -1023,7 +1024,7 @@ static int at_context_queue_packet(struct context *ctx,
*/
if (ohci->generation != packet->generation ||
reg_read(ohci, OHCI1394_IntEventSet) & OHCI1394_busReset) {
if (packet->payload_length > 0)
if (packet->payload_mapped)
dma_unmap_single(ohci->card.device, payload_bus,
packet->payload_length, DMA_TO_DEVICE);
packet->ack = RCODE_GENERATION;
@ -1059,7 +1060,7 @@ static int handle_at_packet(struct context *context,
/* This packet was cancelled, just continue. */
return 1;
if (packet->payload_bus)
if (packet->payload_mapped)
dma_unmap_single(ohci->card.device, packet->payload_bus,
packet->payload_length, DMA_TO_DEVICE);
@ -1723,7 +1724,7 @@ static int ohci_cancel_packet(struct fw_card *card, struct fw_packet *packet)
if (packet->ack != 0)
goto out;
if (packet->payload_bus)
if (packet->payload_mapped)
dma_unmap_single(ohci->card.device, packet->payload_bus,
packet->payload_length, DMA_TO_DEVICE);

1
include/linux/firewire.h
View file

@ -267,6 +267,7 @@ struct fw_packet {
void *payload;
size_t payload_length;
dma_addr_t payload_bus;
bool payload_mapped;
u32 timestamp;
/*