From e91b2787d0a2e4719b016e8dec0afd2d5ab6c30f Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Thu, 10 Jun 2010 08:40:49 +0200 Subject: [PATCH 15/16] firewire: allocate broadcast channel in hardware On OHCI 1.1 controllers, let the hardware allocate the broadcast channel automatically. This removes a theoretical race condition directly after a bus reset where it could be possible to read the channel allocation register with channel 31 still being unallocated. Signed-off-by: Clemens Ladisch --- drivers/firewire/core-card.c | 16 +++++++++++----- drivers/firewire/core-topology.c | 3 ++- drivers/firewire/core.h | 1 + drivers/firewire/ohci.c | 18 ++++++++++++------ 4 files changed, 26 insertions(+), 12 deletions(-) diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c index 7c4cf6c..faf2eee 100644 --- a/drivers/firewire/core-card.c +++ b/drivers/firewire/core-card.c @@ -208,13 +208,19 @@ static void allocate_broadcast_channel(struct fw_card *card, int generation) { int channel, bandwidth = 0; - fw_iso_resource_manage(card, generation, 1ULL << 31, &channel, - &bandwidth, true, card->bm_transaction_data); - if (channel == 31) { + if (!card->broadcast_channel_allocated) { + fw_iso_resource_manage(card, generation, 1ULL << 31, + &channel, &bandwidth, true, + card->bm_transaction_data); + if (channel != 31) { + fw_notify("failed to allocate broadcast channel\n"); + return; + } card->broadcast_channel_allocated = true; - device_for_each_child(card->device, (void *)(long)generation, - fw_device_set_broadcast_channel); } + + device_for_each_child(card->device, (void *)(long)generation, + fw_device_set_broadcast_channel); } static const char gap_count_table[] = { diff --git a/drivers/firewire/core-topology.c b/drivers/firewire/core-topology.c index ca3c653..00a556f 100644 --- a/drivers/firewire/core-topology.c +++ b/drivers/firewire/core-topology.c @@ -543,7 +543,8 @@ void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation, spin_lock_irqsave(&card->lock, flags); - card->broadcast_channel_allocated = false; + card->broadcast_channel_allocated = (card->driver->get_features(card) & + FEATURE_CHANNEL_31_ALLOCATED) != 0; card->node_id = node_id; /* * Update node_id before generation to prevent anybody from using diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h index a9ace1f..3f9e39b 100644 --- a/drivers/firewire/core.h +++ b/drivers/firewire/core.h @@ -39,6 +39,7 @@ struct fw_packet; #define BROADCAST_CHANNEL_VALID (1 << 30) #define FEATURE_PRIORITY_BUDGET 0x01 +#define FEATURE_CHANNEL_31_ALLOCATED 0x02 #define CSR_STATE_BIT_CMSTR (1 << 8) #define CSR_STATE_BIT_ABDICATE (1 << 10) diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index 1dcc2e4..51a5580 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -171,6 +171,7 @@ struct fw_ohci { int request_generation; /* for timestamping incoming requests */ unsigned quirks; unsigned int pri_req_max; + unsigned int features; u32 bus_time; bool is_root; @@ -1694,7 +1695,7 @@ static int ohci_enable(struct fw_card *card, { struct fw_ohci *ohci = fw_ohci(card); struct pci_dev *dev = to_pci_dev(card->device); - u32 lps, seconds, irqs; + u32 lps, seconds, version, irqs; int i, ret; if (software_reset(ohci)) { @@ -1747,10 +1748,19 @@ static int ohci_enable(struct fw_card *card, reg_write(ohci, OHCI1394_IsochronousCycleTimer, seconds << 25); ohci->bus_time = seconds & ~0x3f; + version = reg_read(ohci, OHCI1394_Version) & 0x00ff00ff; + if (version >= OHCI_VERSION_1_1) { + reg_write(ohci, OHCI1394_InitialChannelsAvailableHi, + 0xfffffffe); + ohci->features |= FEATURE_CHANNEL_31_ALLOCATED; + } + /* Get implemented bits of the priority arbitration request counter. */ reg_write(ohci, OHCI1394_FairnessControl, 0x3f); ohci->pri_req_max = reg_read(ohci, OHCI1394_FairnessControl) & 0x3f; reg_write(ohci, OHCI1394_FairnessControl, 0); + if (ohci->pri_req_max != 0) + ohci->features |= FEATURE_PRIORITY_BUDGET; ar_context_run(&ohci->ar_request_ctx); ar_context_run(&ohci->ar_response_ctx); @@ -2124,12 +2134,8 @@ static void ohci_write_csr_reg(struct fw_card *card, int csr_offset, u32 value) static unsigned int ohci_get_features(struct fw_card *card) { struct fw_ohci *ohci = fw_ohci(card); - unsigned int features = 0; - - if (ohci->pri_req_max != 0) - features |= FEATURE_PRIORITY_BUDGET; - return features; + return ohci->features; } static void copy_iso_headers(struct iso_context *ctx, void *p) -- 1.6.4.4