diff options
Diffstat (limited to 'drivers/dma/amba-pl08x.c')
| -rw-r--r-- | drivers/dma/amba-pl08x.c | 36 |
1 files changed, 17 insertions, 19 deletions
diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c index fc8c2bab563c..464725dcad00 100644 --- a/drivers/dma/amba-pl08x.c +++ b/drivers/dma/amba-pl08x.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright (c) 2006 ARM Ltd. * Copyright (c) 2010 ST-Ericsson SA @@ -6,19 +7,6 @@ * Author: Peter Pearse <peter.pearse@arm.com> * Author: Linus Walleij <linus.walleij@linaro.org> * - * This program is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License as published by the Free - * Software Foundation; either version 2 of the License, or (at your option) - * any later version. - * - * This program is distributed in the hope that it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for - * more details. - * - * The full GNU General Public License is in this distribution in the file - * called COPYING. - * * Documentation: ARM DDI 0196G == PL080 * Documentation: ARM DDI 0218E == PL081 * Documentation: S3C6410 User's Manual == PL080S @@ -254,6 +242,7 @@ enum pl08x_dma_chan_state { * @slave: whether this channel is a device (slave) or for memcpy * @signal: the physical DMA request signal which this channel is using * @mux_use: count of descriptors using this DMA request signal setting + * @waiting_at: time in jiffies when this channel moved to waiting state */ struct pl08x_dma_chan { struct virt_dma_chan vc; @@ -267,6 +256,7 @@ struct pl08x_dma_chan { bool slave; int signal; unsigned mux_use; + unsigned long waiting_at; }; /** @@ -875,6 +865,7 @@ static void pl08x_phy_alloc_and_start(struct pl08x_dma_chan *plchan) if (!ch) { dev_dbg(&pl08x->adev->dev, "no physical channel available for xfer on %s\n", plchan->name); plchan->state = PL08X_CHAN_WAITING; + plchan->waiting_at = jiffies; return; } @@ -913,22 +904,29 @@ static void pl08x_phy_free(struct pl08x_dma_chan *plchan) { struct pl08x_driver_data *pl08x = plchan->host; struct pl08x_dma_chan *p, *next; - + unsigned long waiting_at; retry: next = NULL; + waiting_at = jiffies; - /* Find a waiting virtual channel for the next transfer. */ + /* + * Find a waiting virtual channel for the next transfer. + * To be fair, time when each channel reached waiting state is compared + * to select channel that is waiting for the longest time. + */ list_for_each_entry(p, &pl08x->memcpy.channels, vc.chan.device_node) - if (p->state == PL08X_CHAN_WAITING) { + if (p->state == PL08X_CHAN_WAITING && + p->waiting_at <= waiting_at) { next = p; - break; + waiting_at = p->waiting_at; } if (!next && pl08x->has_slave) { list_for_each_entry(p, &pl08x->slave.channels, vc.chan.device_node) - if (p->state == PL08X_CHAN_WAITING) { + if (p->state == PL08X_CHAN_WAITING && + p->waiting_at <= waiting_at) { next = p; - break; + waiting_at = p->waiting_at; } } |