Date: Fri, 26 Jan 2007 00:38:49 -0500 From: Kristian =?utf-8?B?SMO4Z3NiZXJn?= Subject: [PATCH 10/10] firewire: Make sure we wait for DMA to stop before we reprogram it. Signed-off-by: Kristian Høgsberg Signed-off-by: Stefan Richter --- drivers/firewire/fw-ohci.c | 21 ++++++++++++++++----- 1 files changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c index 58bc85d..29285f2 100644 --- a/drivers/firewire/fw-ohci.c +++ b/drivers/firewire/fw-ohci.c @@ -170,6 +170,8 @@ static inline struct fw_ohci *fw_ohci(struct fw_card *card) #define OHCI1394_PCI_HCI_Control 0x40 #define SELF_ID_BUF_SIZE 0x800 +#define MAX_STOP_CONTEXT_LOOPS 1000 + static char ohci_driver_name[] = KBUILD_MODNAME; static inline void reg_write(const struct fw_ohci *ohci, int offset, u32 data) @@ -224,6 +226,13 @@ static void ar_context_tasklet(unsigned long data) struct fw_ohci *ohci = ctx->ohci; struct fw_packet p; u32 status, length, tcode; + int i; + + /* FIXME: We stop and restart the ar context here, what if we + * stop while a receive is in progress? Maybe we could just + * loop the context back to itself and use it in buffer fill + * mode as intended... */ + reg_write(ctx->ohci, ctx->control_clear, CONTEXT_RUN); /* FIXME: What to do about evt_* errors? */ length = le16_to_cpu(ctx->descriptor.req_count) - @@ -287,12 +296,14 @@ static void ar_context_tasklet(unsigned long data) dma_sync_single_for_device(ohci->card.device, ctx->descriptor_bus, sizeof ctx->descriptor_bus, DMA_TO_DEVICE); - /* FIXME: We stop and restart the ar context here, what if we - * stop while a receive is in progress? Maybe we could just - * loop the context back to itself and use it in buffer fill - * mode as intended... */ + /* Make sure the active bit is 0 before we reprogram the DMA. */ + for (i = 0; i < MAX_STOP_CONTEXT_LOOPS; i++) + if (!(reg_read(ctx->ohci, + ctx->control_clear) & CONTEXT_ACTIVE)) + break; + if (i == MAX_STOP_CONTEXT_LOOPS) + fw_error("Failed to stop ar context\n"); - reg_write(ctx->ohci, ctx->control_clear, CONTEXT_RUN); ar_context_run(ctx); } --