4.19-stable review patch. If anyone has any objections, please let me know.
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From: Lucas Stach l.stach@pengutronix.de
commit b8603d2a5795c42f78998e70dc792336e0dc20c9 upstream.
The dmaengine documentation states that device_terminate_all may be asynchronous and need not wait for the active transfers to stop.
This allows us to move most of the functionality currently implemented in the sdma channel termination function to run in a worker, outside of any atomic context. Moving this out of atomic context has two benefits: we can now sleep while waiting for the channel to terminate, instead of busy waiting and the freeing of the dma descriptors happens with IRQs enabled, getting rid of a warning in the dma mapping code.
As the termination is now async, we need to implement the device_synchronize dma engine function which simply waits for the worker to finish its execution.
Signed-off-by: Lucas Stach l.stach@pengutronix.de Signed-off-by: Robin Gong yibin.gong@nxp.com Cc: stable stable@vger.kernel.org Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/dma/imx-sdma.c | 51 ++++++++++++++++++++++++++++++++++++------------- 1 file changed, 38 insertions(+), 13 deletions(-)
--- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -32,6 +32,7 @@ #include <linux/of_address.h> #include <linux/of_device.h> #include <linux/of_dma.h> +#include <linux/workqueue.h>
#include <asm/irq.h> #include <linux/platform_data/dma-imx-sdma.h> @@ -375,6 +376,7 @@ struct sdma_channel { u32 shp_addr, per_addr; enum dma_status status; struct imx_dma_data data; + struct work_struct terminate_worker; };
#define IMX_DMA_SG_LOOP BIT(0) @@ -1025,31 +1027,49 @@ static int sdma_disable_channel(struct d
return 0; } - -static int sdma_disable_channel_with_delay(struct dma_chan *chan) +static void sdma_channel_terminate_work(struct work_struct *work) { - struct sdma_channel *sdmac = to_sdma_chan(chan); + struct sdma_channel *sdmac = container_of(work, struct sdma_channel, + terminate_worker); unsigned long flags; LIST_HEAD(head);
- sdma_disable_channel(chan); - spin_lock_irqsave(&sdmac->vc.lock, flags); - vchan_get_all_descriptors(&sdmac->vc, &head); - sdmac->desc = NULL; - spin_unlock_irqrestore(&sdmac->vc.lock, flags); - vchan_dma_desc_free_list(&sdmac->vc, &head); - /* * According to NXP R&D team a delay of one BD SDMA cost time * (maximum is 1ms) should be added after disable of the channel * bit, to ensure SDMA core has really been stopped after SDMA * clients call .device_terminate_all. */ - mdelay(1); + usleep_range(1000, 2000); + + spin_lock_irqsave(&sdmac->vc.lock, flags); + vchan_get_all_descriptors(&sdmac->vc, &head); + sdmac->desc = NULL; + spin_unlock_irqrestore(&sdmac->vc.lock, flags); + vchan_dma_desc_free_list(&sdmac->vc, &head); +} + +static int sdma_disable_channel_async(struct dma_chan *chan) +{ + struct sdma_channel *sdmac = to_sdma_chan(chan); + + sdma_disable_channel(chan); + + if (sdmac->desc) + schedule_work(&sdmac->terminate_worker);
return 0; }
+static void sdma_channel_synchronize(struct dma_chan *chan) +{ + struct sdma_channel *sdmac = to_sdma_chan(chan); + + vchan_synchronize(&sdmac->vc); + + flush_work(&sdmac->terminate_worker); +} + static void sdma_set_watermarklevel_for_p2p(struct sdma_channel *sdmac) { struct sdma_engine *sdma = sdmac->sdma; @@ -1287,7 +1307,9 @@ static void sdma_free_chan_resources(str struct sdma_channel *sdmac = to_sdma_chan(chan); struct sdma_engine *sdma = sdmac->sdma;
- sdma_disable_channel_with_delay(chan); + sdma_disable_channel_async(chan); + + sdma_channel_synchronize(chan);
if (sdmac->event_id0) sdma_event_disable(sdmac, sdmac->event_id0); @@ -1993,6 +2015,8 @@ static int sdma_probe(struct platform_de
sdmac->channel = i; sdmac->vc.desc_free = sdma_desc_free; + INIT_WORK(&sdmac->terminate_worker, + sdma_channel_terminate_work); /* * Add the channel to the DMAC list. Do not add channel 0 though * because we need it internally in the SDMA driver. This also means @@ -2044,7 +2068,8 @@ static int sdma_probe(struct platform_de sdma->dma_device.device_prep_slave_sg = sdma_prep_slave_sg; sdma->dma_device.device_prep_dma_cyclic = sdma_prep_dma_cyclic; sdma->dma_device.device_config = sdma_config; - sdma->dma_device.device_terminate_all = sdma_disable_channel_with_delay; + sdma->dma_device.device_terminate_all = sdma_disable_channel_async; + sdma->dma_device.device_synchronize = sdma_channel_synchronize; sdma->dma_device.src_addr_widths = SDMA_DMA_BUSWIDTHS; sdma->dma_device.dst_addr_widths = SDMA_DMA_BUSWIDTHS; sdma->dma_device.directions = SDMA_DMA_DIRECTIONS;