lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 12 Sep 2012 17:35:56 +0300 From: Peter Ujfalusi <peter.ujfalusi@...com> To: Russell King - ARM Linux <linux@....linux.org.uk> CC: Mark Brown <broonie@...nsource.wolfsonmicro.com>, Liam Girdwood <lrg@...com>, Tony Lindgren <tony@...mide.com>, Vinod Koul <vinod.koul@...el.com>, Dan Williams <djbw@...com>, Jarkko Nikula <jarkko.nikula@...mer.com>, alsa-devel@...a-project.org, linux-omap@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, Janusz Krzysztofik <jkrzyszt@....icnet.pl>, Ricardo Neri <ricardo.neri@...com> Subject: Re: [PATCH 11/11] ASoC: omap-pcm: Convert to use dmaengine On 09/12/2012 03:53 PM, Peter Ujfalusi wrote: > I need to look at this, but at first look we do wait for the drain in > omap_stop_dma(). We used to use omap_stop_dma/omap_start_dma for pause/resume > operations. > But sDMA also have a bit: CDPi: PAUSE_LINK_LIST which should do what we are > looking for. > Need to read the relevant parts of the TRM, but AFAIK we are using normal mode > with linked list (self linking). > I already have the patch for this, I just need to test it on HW. We can get the PAUSE/RESUME work either: 1. drivers/dma/omap-dma.c static int omap_dma_pause(struct omap_chan *c) { - /* FIXME: not supported by platform private API */ - return -EINVAL; + /* Only in cyclic mode */ + if (!c->cyclic) + return -EINVAL; + + if (!c->paused) { + omap_stop_dma(c->dma_ch); + c->paused = true; + } + + return 0; } static int omap_dma_resume(struct omap_chan *c) { - /* FIXME: not supported by platform private API */ - return -EINVAL; + /* Only in cyclic mode */ + if (!c->cyclic) + return -EINVAL; + + if (c->paused) { + omap_start_dma(c->dma_ch); + c->paused = false; + } + + return 0; } 2. arch/arm/plat-omap/dma.c +void omap_pause_linked_dma(int lch) +{ + u32 l; + unsigned long flags; + + local_irq_save(flags); + l = p->dma_read(CDP, lch); + l |= 0x80; /* PAUSE_LINK_LIST */ + p->dma_write(l, CDP, lch); + local_irq_restore(flags); +} +EXPORT_SYMBOL(omap_pause_linked_dma); + +void omap_resume_linked_dma(int lch) +{ + u32 l; + unsigned long flags; + + local_irq_save(flags); + l = p->dma_read(CDP, lch); + l &= (~0x80); /* PAUSE_LINK_LIST */ + p->dma_write(l, CDP, lch); + local_irq_restore(flags); +} +EXPORT_SYMBOL(omap_resume_linked_dma); drivers/dma/omap-dma.c static int omap_dma_pause(struct omap_chan *c) { - /* FIXME: not supported by platform private API */ - return -EINVAL; + /* Only in cyclic mode */ + if (!c->cyclic) + return -EINVAL; + + if (!c->paused) { + omap_pause_linked_dma(c->dma_ch); + c->paused = true; + } + + return 0; } static int omap_dma_resume(struct omap_chan *c) { - /* FIXME: not supported by platform private API */ - return -EINVAL; + /* Only in cyclic mode */ + if (!c->cyclic) + return -EINVAL; + + if (c->paused) { + omap_resume_linked_dma(c->dma_ch); + c->paused = false; + } + + return 0; } Both works fine (have tested it on BeagleBoard with mplayer). With [1] we have identical way of dealing with the PAUSE/RESUME as we had previously, so it is know to work fine on OMAP1/2/3/4/5 We have never used [2] in the past, but I think that is not going to work on OMAP1 and OMAP2420. Also we need to add code to arch/arm/plat-omap/dma.c for this... I can resend the series with either of these to fix this regression caused by the dmaengine conversion (after cleanup off course). -- Péter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists