Re: [PATCH 1/7 v2] dmaengine: add a simple dma library
From: "Shimoda, Yoshihiro" <yoshihiro.shimoda.uh@renesas.com>
Date: 2012-01-27 08:37:38
Also in:
alsa-devel, linux-mmc, linux-sh, lkml
Subsystem:
dma generic offload engine subsystem, the rest · Maintainers:
Vinod Koul, Linus Torvalds
Hello Guennadi-san, 2012/01/26 23:56, Guennadi Liakhovetski wrote:
This patch adds a library of functions, helping to implement dmaengine drivers for hardware, unable to handle scatter-gather lists natively. The first version of this driver only supports memcpy and slave DMA operation. Signed-off-by: Guennadi Liakhovetski <redacted> --- v2: 1. switch from using a tasklet to threaded IRQ, which allowed to
I tested this driver on 2 environment, but it could not work correctly. - renesas_usbhs driver with shdma driver on the mackerel board - renesas_usbhs driver with experimental SUDMAC driver In this case, should we modify the renesas_usbhs driver? For reference, if I changed the threaded IRQ to tasklet, the 2 environment worked correctly: ==============
diff --git a/drivers/dma/dma-simple.c b/drivers/dma/dma-simple.c
index 49d8f7d..65a5170 100644
--- a/drivers/dma/dma-simple.c
+++ b/drivers/dma/dma-simple.c@@ -715,16 +715,18 @@ static irqreturn_t chan_irq(int irq, void *dev) spin_lock(&schan->chan_lock); - ret = ops->chan_irq(schan, irq) ? IRQ_WAKE_THREAD : IRQ_NONE; + ret = ops->chan_irq(schan, irq) ? IRQ_HANDLED : IRQ_NONE; + if (ret == IRQ_HANDLED) + tasklet_schedule(&schan->tasklet); spin_unlock(&schan->chan_lock); return ret; } -static irqreturn_t chan_irqt(int irq, void *dev) +static void chan_irqt(unsigned long dev) { - struct dma_simple_chan *schan = dev; + struct dma_simple_chan *schan = (struct dma_simple_chan *)dev; const struct dma_simple_ops *ops = to_simple_dev(schan->dma_chan.device)->ops; struct dma_simple_desc *sdesc;
@@ -744,15 +746,13 @@ static irqreturn_t chan_irqt(int irq, void *dev) spin_unlock_irq(&schan->chan_lock); simple_chan_ld_cleanup(schan, false); - - return IRQ_HANDLED; } int dma_simple_request_irq(struct dma_simple_chan *schan, int irq, unsigned long flags, const char *name) { - int ret = request_threaded_irq(irq, chan_irq, chan_irqt, - flags, name, schan); + int ret = request_irq(irq, chan_irq, flags, name, schan); + tasklet_init(&schan->tasklet, chan_irqt, (unsigned long)schan); schan->irq = ret < 0 ? ret : irq;
diff --git a/include/linux/dma-simple.h b/include/linux/dma-simple.h
index 5336674..beb1489 100644
--- a/include/linux/dma-simple.h
+++ b/include/linux/dma-simple.h@@ -68,6 +68,7 @@ struct dma_simple_chan { int id; /* Raw id of this channel */ int irq; /* Channel IRQ */ enum dma_simple_pm_state pm_state; + struct tasklet_struct tasklet; }; /**
============== Best regards, Yoshihiro Shimoda