rapidio: fix blocking wait for discovery ready
The following set of patches provides modifications targeting support of multiple RapidIO master port (mport) devices on a CPU-side of RapidIO-capable board. While the RapidIO subsystem code has definitions suitable for multi-controller/multi-net support, the existing implementation cannot be considered ready for multiple mport configurations. =========== NOTES: ============= a) The patches below do not address RapidIO side view of multiport processing elements defined in Part 6 of RapidIO spec Rev.2.1 (section 6.4.1). These devices have Base Device ID CSR (0x60) and Component Tag CSR (0x6C) shared by all SRIO ports. For example, Freescale's P4080, P3041 and P5020 have a dual-port SRIO controller implemented according the specification. Enumeration/discovery of such devices from RapidIO side may require device-specific fixups. b) Devices referenced above may also require implementation specific code to setup a host device ID for mport device. These operations are not addressed by patches in this package. ================================= Details about provided patches: 1. Fix blocking wait for discovery ready While it does not happen on PowerPC based platforms, there is possibility of stalled CPU warning dump on x86 based platforms that run RapidIO discovery process if they wait too long for being enumerated. Currently users can avoid it by disabling the soft-lockup detector using "nosoftlockup" kernel parameter OR by ensuring that enumeration is completed before soft-lockup is detected. This patch eliminates blocking wait and keeps a scheduler running. It also is required for patch 3 below which introduces asynchronous discovery process. 2. Use device lists handling on per-net basis This patch allows to correctly support multiple RapidIO nets and resolves possible issues caused by using single global list of devices during RapidIO system enumeration/discovery. The most common sign of existing issue is incorrect contents of switch routing tables in systems with multiple mport controllers while single-port configuration performs as expected. The patch does not eliminate the global RapidIO device list but changes some routines in enumeration/discovery to use per-net device lists instead. This way compatibility with upper layer RIO routines is preserved. 3. Run discovery as an asynchronous process This patch modifies RapidIO initialization routine to asynchronously run the discovery process for each corresponding mport. This allows having an arbitrary order of enumerating and discovering mports without creating a deadlock situation if an enumerator port was registered after a discovering one. On boards with multiple discovering mports it also eliminates order dependency between mports and may reduce total time of RapidIO subsystem initialization. Making netID matching to mportID ensures consistent netID assignment in multiport RapidIO systems with asynchronous discovery process (global counter implementation is affected by race between threads). 4. Rework RIONET to support multiple RIO master ports In the current version of the driver rionet_probe() has comment "XXX Make multi-net safe". Now it is a good time to address this comment. This patch makes RIONET driver multi-net safe/capable by introducing per-net lists of RapidIO network peers. It also enables to register network adapters for all available mport devices. 5. Add destination ID allocation mechanism The patch replaces a single global destination ID counter with per-net allocation mechanism to allow independent destID management for each available RapidIO network. Using bitmap based mechanism instead of counters allows destination ID release and reuse in systems that support hot-swap. This patch: Fix blocking wait loop in the RapidIO discovery routine to avoid warning dumps about stalled CPU on x86 platforms. Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com> Cc: Matt Porter <mporter@kernel.crashing.org> Cc: Li Yang <leoli@freescale.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexandre Bounine
Linus Torvalds
parent
8d4630dcf4
commit
fa3dbaa010
@ -31,6 +31,7 @@
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/timer.h>
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#include <linux/sched.h>
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#include <linux/jiffies.h>
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#include <linux/slab.h>
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@ -39,8 +40,6 @@
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LIST_HEAD(rio_devices);
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static LIST_HEAD(rio_switches);
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static void rio_enum_timeout(unsigned long);
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static void rio_init_em(struct rio_dev *rdev);
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DEFINE_SPINLOCK(rio_global_list_lock);
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@ -49,9 +48,6 @@ static int next_destid = 0;
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static int next_net = 0;
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static int next_comptag = 1;
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static struct timer_list rio_enum_timer =
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TIMER_INITIALIZER(rio_enum_timeout, 0, 0);
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static int rio_mport_phys_table[] = {
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RIO_EFB_PAR_EP_ID,
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RIO_EFB_PAR_EP_REC_ID,
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@ -1233,20 +1229,6 @@ static void rio_build_route_tables(void)
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}
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}
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/**
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* rio_enum_timeout- Signal that enumeration timed out
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* @data: Address of timeout flag.
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*
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* When the enumeration complete timer expires, set a flag that
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* signals to the discovery process that enumeration did not
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* complete in a sane amount of time.
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*/
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static void rio_enum_timeout(unsigned long data)
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{
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/* Enumeration timed out, set flag */
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*(int *)data = 1;
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}
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/**
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* rio_disc_mport- Start discovery through a master port
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* @mport: Master port to send transactions
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@ -1260,35 +1242,34 @@ static void rio_enum_timeout(unsigned long data)
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int __devinit rio_disc_mport(struct rio_mport *mport)
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{
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struct rio_net *net = NULL;
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int enum_timeout_flag = 0;
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unsigned long to_end;
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printk(KERN_INFO "RIO: discover master port %d, %s\n", mport->id,
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mport->name);
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/* If master port has an active link, allocate net and discover peers */
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if (rio_mport_is_active(mport)) {
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if (!(net = rio_alloc_net(mport))) {
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pr_debug("RIO: wait for enumeration to complete...\n");
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to_end = jiffies + CONFIG_RAPIDIO_DISC_TIMEOUT * HZ;
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while (time_before(jiffies, to_end)) {
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if (rio_enum_complete(mport))
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goto enum_done;
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schedule_timeout_uninterruptible(msecs_to_jiffies(10));
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}
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pr_debug("RIO: discovery timeout on mport %d %s\n",
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mport->id, mport->name);
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goto bail;
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enum_done:
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pr_debug("RIO: ... enumeration done\n");
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net = rio_alloc_net(mport);
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if (!net) {
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printk(KERN_ERR "RIO: Failed to allocate new net\n");
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goto bail;
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}
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pr_debug("RIO: wait for enumeration complete...");
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rio_enum_timer.expires =
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jiffies + CONFIG_RAPIDIO_DISC_TIMEOUT * HZ;
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rio_enum_timer.data = (unsigned long)&enum_timeout_flag;
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add_timer(&rio_enum_timer);
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while (!rio_enum_complete(mport)) {
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mdelay(1);
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if (enum_timeout_flag) {
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del_timer_sync(&rio_enum_timer);
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goto timeout;
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}
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}
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del_timer_sync(&rio_enum_timer);
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pr_debug("done\n");
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/* Read DestID assigned by enumerator */
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rio_local_read_config_32(mport, RIO_DID_CSR,
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&mport->host_deviceid);
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@ -1307,9 +1288,6 @@ int __devinit rio_disc_mport(struct rio_mport *mport)
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}
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return 0;
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timeout:
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pr_debug("timeout\n");
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bail:
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bail:
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return -EBUSY;
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}
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