cregit-Linux how code gets into the kernel

Release 4.7 drivers/infiniband/hw/qib/qib_tx.c

/*
 * Copyright (c) 2008, 2009, 2010 QLogic Corporation. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/spinlock.h>
#include <linux/pci.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/vmalloc.h>
#include <linux/moduleparam.h>

#include "qib.h"


static unsigned qib_hol_timeout_ms = 3000;
module_param_named(hol_timeout_ms, qib_hol_timeout_ms, uint, S_IRUGO);
MODULE_PARM_DESC(hol_timeout_ms,
		 "duration of user app suspension after link failure");


unsigned qib_sdma_fetch_arb = 1;
module_param_named(fetch_arb, qib_sdma_fetch_arb, uint, S_IRUGO);
MODULE_PARM_DESC(fetch_arb, "IBA7220: change SDMA descriptor arbitration");

/**
 * qib_disarm_piobufs - cancel a range of PIO buffers
 * @dd: the qlogic_ib device
 * @first: the first PIO buffer to cancel
 * @cnt: the number of PIO buffers to cancel
 *
 * Cancel a range of PIO buffers. Used at user process close,
 * in case it died while writing to a PIO buffer.
 */

void qib_disarm_piobufs(struct qib_devdata *dd, unsigned first, unsigned cnt) { unsigned long flags; unsigned i; unsigned last; last = first + cnt; spin_lock_irqsave(&dd->pioavail_lock, flags); for (i = first; i < last; i++) { __clear_bit(i, dd->pio_need_disarm); dd->f_sendctrl(dd->pport, QIB_SENDCTRL_DISARM_BUF(i)); } spin_unlock_irqrestore(&dd->pioavail_lock, flags); }

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/* * This is called by a user process when it sees the DISARM_BUFS event * bit is set. */
int qib_disarm_piobufs_ifneeded(struct qib_ctxtdata *rcd) { struct qib_devdata *dd = rcd->dd; unsigned i; unsigned last; unsigned n = 0; last = rcd->pio_base + rcd->piocnt; /* * Don't need uctxt_lock here, since user has called in to us. * Clear at start in case more interrupts set bits while we * are disarming */ if (rcd->user_event_mask) { /* * subctxt_cnt is 0 if not shared, so do base * separately, first, then remaining subctxt, if any */ clear_bit(_QIB_EVENT_DISARM_BUFS_BIT, &rcd->user_event_mask[0]); for (i = 1; i < rcd->subctxt_cnt; i++) clear_bit(_QIB_EVENT_DISARM_BUFS_BIT, &rcd->user_event_mask[i]); } spin_lock_irq(&dd->pioavail_lock); for (i = rcd->pio_base; i < last; i++) { if (__test_and_clear_bit(i, dd->pio_need_disarm)) { n++; dd->f_sendctrl(rcd->ppd, QIB_SENDCTRL_DISARM_BUF(i)); } } spin_unlock_irq(&dd->pioavail_lock); return 0; }

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static struct qib_pportdata *is_sdma_buf(struct qib_devdata *dd, unsigned i) { struct qib_pportdata *ppd; unsigned pidx; for (pidx = 0; pidx < dd->num_pports; pidx++) { ppd = dd->pport + pidx; if (i >= ppd->sdma_state.first_sendbuf && i < ppd->sdma_state.last_sendbuf) return ppd; } return NULL; }

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/* * Return true if send buffer is being used by a user context. * Sets _QIB_EVENT_DISARM_BUFS_BIT in user_event_mask as a side effect */
static int find_ctxt(struct qib_devdata *dd, unsigned bufn) { struct qib_ctxtdata *rcd; unsigned ctxt; int ret = 0; spin_lock(&dd->uctxt_lock); for (ctxt = dd->first_user_ctxt; ctxt < dd->cfgctxts; ctxt++) { rcd = dd->rcd[ctxt]; if (!rcd || bufn < rcd->pio_base || bufn >= rcd->pio_base + rcd->piocnt) continue; if (rcd->user_event_mask) { int i; /* * subctxt_cnt is 0 if not shared, so do base * separately, first, then remaining subctxt, if any */ set_bit(_QIB_EVENT_DISARM_BUFS_BIT, &rcd->user_event_mask[0]); for (i = 1; i < rcd->subctxt_cnt; i++) set_bit(_QIB_EVENT_DISARM_BUFS_BIT, &rcd->user_event_mask[i]); } ret = 1; break; } spin_unlock(&dd->uctxt_lock); return ret; }

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/* * Disarm a set of send buffers. If the buffer might be actively being * written to, mark the buffer to be disarmed later when it is not being * written to. * * This should only be called from the IRQ error handler. */
void qib_disarm_piobufs_set(struct qib_devdata *dd, unsigned long *mask, unsigned cnt) { struct qib_pportdata *ppd, *pppd[QIB_MAX_IB_PORTS]; unsigned i; unsigned long flags; for (i = 0; i < dd->num_pports; i++) pppd[i] = NULL; for (i = 0; i < cnt; i++) { int which; if (!test_bit(i, mask)) continue; /* * If the buffer is owned by the DMA hardware, * reset the DMA engine. */ ppd = is_sdma_buf(dd, i); if (ppd) { pppd[ppd->port] = ppd; continue; } /* * If the kernel is writing the buffer or the buffer is * owned by a user process, we can't clear it yet. */ spin_lock_irqsave(&dd->pioavail_lock, flags); if (test_bit(i, dd->pio_writing) || (!test_bit(i << 1, dd->pioavailkernel) && find_ctxt(dd, i))) { __set_bit(i, dd->pio_need_disarm); which = 0; } else { which = 1; dd->f_sendctrl(dd->pport, QIB_SENDCTRL_DISARM_BUF(i)); } spin_unlock_irqrestore(&dd->pioavail_lock, flags); } /* do cancel_sends once per port that had sdma piobufs in error */ for (i = 0; i < dd->num_pports; i++) if (pppd[i]) qib_cancel_sends(pppd[i]); }

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/** * update_send_bufs - update shadow copy of the PIO availability map * @dd: the qlogic_ib device * * called whenever our local copy indicates we have run out of send buffers */
static void update_send_bufs(struct qib_devdata *dd) { unsigned long flags; unsigned i; const unsigned piobregs = dd->pioavregs; /* * If the generation (check) bits have changed, then we update the * busy bit for the corresponding PIO buffer. This algorithm will * modify positions to the value they already have in some cases * (i.e., no change), but it's faster than changing only the bits * that have changed. * * We would like to do this atomicly, to avoid spinlocks in the * critical send path, but that's not really possible, given the * type of changes, and that this routine could be called on * multiple cpu's simultaneously, so we lock in this routine only, * to avoid conflicting updates; all we change is the shadow, and * it's a single 64 bit memory location, so by definition the update * is atomic in terms of what other cpu's can see in testing the * bits. The spin_lock overhead isn't too bad, since it only * happens when all buffers are in use, so only cpu overhead, not * latency or bandwidth is affected. */ if (!dd->pioavailregs_dma) return; spin_lock_irqsave(&dd->pioavail_lock, flags); for (i = 0; i < piobregs; i++) { u64 pchbusy, pchg, piov, pnew; piov = le64_to_cpu(dd->pioavailregs_dma[i]); pchg = dd->pioavailkernel[i] & ~(dd->pioavailshadow[i] ^ piov); pchbusy = pchg << QLOGIC_IB_SENDPIOAVAIL_BUSY_SHIFT; if (pchg && (pchbusy & dd->pioavailshadow[i])) { pnew = dd->pioavailshadow[i] & ~pchbusy; pnew |= piov & pchbusy; dd->pioavailshadow[i] = pnew; } } spin_unlock_irqrestore(&dd->pioavail_lock, flags); }

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/* * Debugging code and stats updates if no pio buffers available. */
static noinline void no_send_bufs(struct qib_devdata *dd) { dd->upd_pio_shadow = 1; /* not atomic, but if we lose a stat count in a while, that's OK */ qib_stats.sps_nopiobufs++; }

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/* * Common code for normal driver send buffer allocation, and reserved * allocation. * * Do appropriate marking as busy, etc. * Returns buffer pointer if one is found, otherwise NULL. */
u32 __iomem *qib_getsendbuf_range(struct qib_devdata *dd, u32 *pbufnum, u32 first, u32 last) { unsigned i, j, updated = 0; unsigned nbufs; unsigned long flags; unsigned long *shadow = dd->pioavailshadow; u32 __iomem *buf; if (!(dd->flags & QIB_PRESENT)) return NULL; nbufs = last - first + 1; /* number in range to check */ if (dd->upd_pio_shadow) { update_shadow: /* * Minor optimization. If we had no buffers on last call, * start out by doing the update; continue and do scan even * if no buffers were updated, to be paranoid. */ update_send_bufs(dd); updated++; } i = first; /* * While test_and_set_bit() is atomic, we do that and then the * change_bit(), and the pair is not. See if this is the cause * of the remaining armlaunch errors. */ spin_lock_irqsave(&dd->pioavail_lock, flags); if (dd->last_pio >= first && dd->last_pio <= last) i = dd->last_pio + 1; if (!first) /* adjust to min possible */ nbufs = last - dd->min_kernel_pio + 1; for (j = 0; j < nbufs; j++, i++) { if (i > last) i = !first ? dd->min_kernel_pio : first; if (__test_and_set_bit((2 * i) + 1, shadow)) continue; /* flip generation bit */ __change_bit(2 * i, shadow); /* remember that the buffer can be written to now */ __set_bit(i, dd->pio_writing); if (!first && first != last) /* first == last on VL15, avoid */ dd->last_pio = i; break; } spin_unlock_irqrestore(&dd->pioavail_lock, flags); if (j == nbufs) { if (!updated) /* * First time through; shadow exhausted, but may be * buffers available, try an update and then rescan. */ goto update_shadow; no_send_bufs(dd); buf = NULL; } else { if (i < dd->piobcnt2k) buf = (u32 __iomem *)(dd->pio2kbase + i * dd->palign); else if (i < dd->piobcnt2k + dd->piobcnt4k || !dd->piovl15base) buf = (u32 __iomem *)(dd->pio4kbase + (i - dd->piobcnt2k) * dd->align4k); else buf = (u32 __iomem *)(dd->piovl15base + (i - (dd->piobcnt2k + dd->piobcnt4k)) * dd->align4k); if (pbufnum) *pbufnum = i; dd->upd_pio_shadow = 0; } return buf; }

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/* * Record that the caller is finished writing to the buffer so we don't * disarm it while it is being written and disarm it now if needed. */
void qib_sendbuf_done(struct qib_devdata *dd, unsigned n) { unsigned long flags; spin_lock_irqsave(&dd->pioavail_lock, flags); __clear_bit(n, dd->pio_writing); if (__test_and_clear_bit(n, dd->pio_need_disarm)) dd->f_sendctrl(dd->pport, QIB_SENDCTRL_DISARM_BUF(n)); spin_unlock_irqrestore(&dd->pioavail_lock, flags); }

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/** * qib_chg_pioavailkernel - change which send buffers are available for kernel * @dd: the qlogic_ib device * @start: the starting send buffer number * @len: the number of send buffers * @avail: true if the buffers are available for kernel use, false otherwise */
void qib_chg_pioavailkernel(struct qib_devdata *dd, unsigned start, unsigned len, u32 avail, struct qib_ctxtdata *rcd) { unsigned long flags; unsigned end; unsigned ostart = start; /* There are two bits per send buffer (busy and generation) */ start *= 2; end = start + len * 2; spin_lock_irqsave(&dd->pioavail_lock, flags); /* Set or clear the busy bit in the shadow. */ while (start < end) { if (avail) { unsigned long dma; int i; /* * The BUSY bit will never be set, because we disarm * the user buffers before we hand them back to the * kernel. We do have to make sure the generation * bit is set correctly in shadow, since it could * have changed many times while allocated to user. * We can't use the bitmap functions on the full * dma array because it is always little-endian, so * we have to flip to host-order first. * BITS_PER_LONG is slightly wrong, since it's * always 64 bits per register in chip... * We only work on 64 bit kernels, so that's OK. */ i = start / BITS_PER_LONG; __clear_bit(QLOGIC_IB_SENDPIOAVAIL_BUSY_SHIFT + start, dd->pioavailshadow); dma = (unsigned long) le64_to_cpu(dd->pioavailregs_dma[i]); if (test_bit((QLOGIC_IB_SENDPIOAVAIL_CHECK_SHIFT + start) % BITS_PER_LONG, &dma)) __set_bit(QLOGIC_IB_SENDPIOAVAIL_CHECK_SHIFT + start, dd->pioavailshadow); else __clear_bit(QLOGIC_IB_SENDPIOAVAIL_CHECK_SHIFT + start, dd->pioavailshadow); __set_bit(start, dd->pioavailkernel); if ((start >> 1) < dd->min_kernel_pio) dd->min_kernel_pio = start >> 1; } else { __set_bit(start + QLOGIC_IB_SENDPIOAVAIL_BUSY_SHIFT, dd->pioavailshadow); __clear_bit(start, dd->pioavailkernel); if ((start >> 1) > dd->min_kernel_pio) dd->min_kernel_pio = start >> 1; } start += 2; } if (dd->min_kernel_pio > 0 && dd->last_pio < dd->min_kernel_pio - 1) dd->last_pio = dd->min_kernel_pio - 1; spin_unlock_irqrestore(&dd->pioavail_lock, flags); dd->f_txchk_change(dd, ostart, len, avail, rcd); }

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/* * Flush all sends that might be in the ready to send state, as well as any * that are in the process of being sent. Used whenever we need to be * sure the send side is idle. Cleans up all buffer state by canceling * all pio buffers, and issuing an abort, which cleans up anything in the * launch fifo. The cancel is superfluous on some chip versions, but * it's safer to always do it. * PIOAvail bits are updated by the chip as if a normal send had happened. */
void qib_cancel_sends(struct qib_pportdata *ppd) { struct qib_devdata *dd = ppd->dd; struct qib_ctxtdata *rcd; unsigned long flags; unsigned ctxt; unsigned i; unsigned last; /* * Tell PSM to disarm buffers again before trying to reuse them. * We need to be sure the rcd doesn't change out from under us * while we do so. We hold the two locks sequentially. We might * needlessly set some need_disarm bits as a result, if the * context is closed after we release the uctxt_lock, but that's * fairly benign, and safer than nesting the locks. */ for (ctxt = dd->first_user_ctxt; ctxt < dd->cfgctxts; ctxt++) { spin_lock_irqsave(&dd->uctxt_lock, flags); rcd = dd->rcd[ctxt]; if (rcd && rcd->ppd == ppd) { last = rcd->pio_base + rcd->piocnt; if (rcd->user_event_mask) { /* * subctxt_cnt is 0 if not shared, so do base * separately, first, then remaining subctxt, * if any */ set_bit(_QIB_EVENT_DISARM_BUFS_BIT, &rcd->user_event_mask[0]); for (i = 1; i < rcd->subctxt_cnt; i++) set_bit(_QIB_EVENT_DISARM_BUFS_BIT, &rcd->user_event_mask[i]); } i = rcd->pio_base; spin_unlock_irqrestore(&dd->uctxt_lock, flags); spin_lock_irqsave(&dd->pioavail_lock, flags); for (; i < last; i++) __set_bit(i, dd->pio_need_disarm); spin_unlock_irqrestore(&dd->pioavail_lock, flags); } else spin_unlock_irqrestore(&dd->uctxt_lock, flags); } if (!(dd->flags & QIB_HAS_SEND_DMA)) dd->f_sendctrl(ppd, QIB_SENDCTRL_DISARM_ALL | QIB_SENDCTRL_FLUSH); }

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/* * Force an update of in-memory copy of the pioavail registers, when * needed for any of a variety of reasons. * If already off, this routine is a nop, on the assumption that the * caller (or set of callers) will "do the right thing". * This is a per-device operation, so just the first port. */
void qib_force_pio_avail_update(struct qib_devdata *dd) { dd->f_sendctrl(dd->pport, QIB_SENDCTRL_AVAIL_BLIP); }

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void qib_hol_down(struct qib_pportdata *ppd) { /* * Cancel sends when the link goes DOWN so that we aren't doing it * at INIT when we might be trying to send SMI packets. */ if (!(ppd->lflags & QIBL_IB_AUTONEG_INPROG)) qib_cancel_sends(ppd); }

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/* * Link is at INIT. * We start the HoL timer so we can detect stuck packets blocking SMP replies. * Timer may already be running, so use mod_timer, not add_timer. */
void qib_hol_init(struct qib_pportdata *ppd) { if (ppd->hol_state != QIB_HOL_INIT) { ppd->hol_state = QIB_HOL_INIT; mod_timer(&ppd->hol_timer, jiffies + msecs_to_jiffies(qib_hol_timeout_ms)); } }

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/* * Link is up, continue any user processes, and ensure timer * is a nop, if running. Let timer keep running, if set; it * will nop when it sees the link is up. */
void qib_hol_up(struct qib_pportdata *ppd) { ppd->hol_state = QIB_HOL_UP; }

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/* * This is only called via the timer. */
void qib_hol_event(unsigned long opaque) { struct qib_pportdata *ppd = (struct qib_pportdata *)opaque; /* If hardware error, etc, skip. */ if (!(ppd->dd->flags & QIB_INITTED)) return; if (ppd->hol_state != QIB_HOL_UP) { /* * Try to flush sends in case a stuck packet is blocking * SMP replies. */ qib_hol_down(ppd); mod_timer(&ppd->hol_timer, jiffies + msecs_to_jiffies(qib_hol_timeout_ms)); } }

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