From 21585ee848078b12d0d1a513e93936bf96b444a0 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Thu, 28 Nov 2013 08:50:32 +0100 Subject: [PATCH 1/8] ASoC: Add resource managed snd_dmaengine_pcm_register() For many drivers using the generic dmaengine PCM driver one of the few (or the only) things left to do in the drivers remove function is to unregister the PCM device. This patch adds a resource managed version of snd_dmaengine_pcm_register() which makes it possible to simplify the remove function as well as the error path in the probe function for those drivers. Signed-off-by: Lars-Peter Clausen Signed-off-by: Mark Brown --- include/sound/dmaengine_pcm.h | 4 ++++ sound/soc/soc-devres.c | 41 +++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+) diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h index 15017311f2e9..4ef986cab182 100644 --- a/include/sound/dmaengine_pcm.h +++ b/include/sound/dmaengine_pcm.h @@ -140,6 +140,10 @@ int snd_dmaengine_pcm_register(struct device *dev, unsigned int flags); void snd_dmaengine_pcm_unregister(struct device *dev); +int devm_snd_dmaengine_pcm_register(struct device *dev, + const struct snd_dmaengine_pcm_config *config, + unsigned int flags); + int snd_dmaengine_pcm_prepare_slave_config(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config); diff --git a/sound/soc/soc-devres.c b/sound/soc/soc-devres.c index b1d732255c02..999861942d28 100644 --- a/sound/soc/soc-devres.c +++ b/sound/soc/soc-devres.c @@ -12,6 +12,7 @@ #include #include #include +#include static void devm_component_release(struct device *dev, void *res) { @@ -84,3 +85,43 @@ int devm_snd_soc_register_card(struct device *dev, struct snd_soc_card *card) return ret; } EXPORT_SYMBOL_GPL(devm_snd_soc_register_card); + +#ifdef CONFIG_SND_SOC_GENERIC_DMAENGINE_PCM + +static void devm_dmaengine_pcm_release(struct device *dev, void *res) +{ + snd_dmaengine_pcm_unregister(*(struct device **)res); +} + +/** + * devm_snd_dmaengine_pcm_register - resource managed dmaengine PCM registration + * @dev: The parent device for the PCM device + * @config: Platform specific PCM configuration + * @flags: Platform specific quirks + * + * Register a dmaengine based PCM device with automatic unregistration when the + * device is unregistered. + */ +int devm_snd_dmaengine_pcm_register(struct device *dev, + const struct snd_dmaengine_pcm_config *config, unsigned int flags) +{ + struct device **ptr; + int ret; + + ptr = devres_alloc(devm_dmaengine_pcm_release, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return -ENOMEM; + + ret = snd_dmaengine_pcm_register(dev, config, flags); + if (ret == 0) { + *ptr = dev; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return ret; +} +EXPORT_SYMBOL_GPL(devm_snd_dmaengine_pcm_register); + +#endif From a22f33b00346f26d29483cdacdbf26df7947ef23 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Sat, 30 Nov 2013 18:00:45 +0100 Subject: [PATCH 2/8] ASoC: generic-dmaengine-pcm: Set BATCH flag when residue reporting is not supported For dmaengine drivers which do not support transfer residue reporting we update the PCM pointer with period granularity. Set the SNDRV_PCM_INFO_BATCH flag in this case to let userspace know about this. Signed-off-by: Lars-Peter Clausen Signed-off-by: Mark Brown --- sound/soc/soc-generic-dmaengine-pcm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index cbc9c96ce1f4..87e86357124e 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -137,6 +137,9 @@ static int dmaengine_pcm_set_runtime_hwparams(struct snd_pcm_substream *substrea hw.buffer_bytes_max = SIZE_MAX; hw.fifo_size = dma_data->fifo_size; + if (pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE) + hw.info |= SNDRV_PCM_INFO_BATCH; + ret = dma_get_slave_caps(chan, &dma_caps); if (ret == 0) { if (dma_caps.cmd_pause) From 11b3a7add2841aa698aa0a32396b6db413c22eda Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Tue, 3 Dec 2013 14:26:32 -0700 Subject: [PATCH 3/8] ASoC: restructure dmaengine_pcm_request_chan_of() Restructure the internals of dmaengine_pcm_request_chan_of() as a loop over all channels to be allocated. This makes it easier to add logic that applies to all allocated channels, without having to duplicate that logic in each of the half-duplex/full-duplex paths. Signed-off-by: Stephen Warren Acked-by: Lars-Peter Clausen Signed-off-by: Mark Brown --- sound/soc/soc-generic-dmaengine-pcm.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index 87e86357124e..fbc28a799e06 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -291,21 +291,26 @@ static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, struct device *dev) { unsigned int i; + const char *name; if ((pcm->flags & (SND_DMAENGINE_PCM_FLAG_NO_DT | SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME)) || !dev->of_node) return; - if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) { - pcm->chan[0] = dma_request_slave_channel(dev, "rx-tx"); - pcm->chan[1] = pcm->chan[0]; - } else { - for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) { - pcm->chan[i] = dma_request_slave_channel(dev, - dmaengine_pcm_dma_channel_names[i]); - } + for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; + i++) { + if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) + name = "rx-tx"; + else + name = dmaengine_pcm_dma_channel_names[i]; + pcm->chan[i] = dma_request_slave_channel(dev, name); + if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) + break; } + + if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) + pcm->chan[1] = pcm->chan[0]; } /** From 194c7dea00c68c1b1f8ff26304fa937a006f66dd Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Tue, 3 Dec 2013 14:26:34 -0700 Subject: [PATCH 4/8] ASoC: dmaengine: add custom DMA config to snd_dmaengine_pcm_config Add fields to struct snd_dmaengine_pcm_config to allow custom: - DMA channel names. This is useful when the default "tx" and "rx" channel names don't apply, for example if a HW module supports multiple channels, each having different DMA channel names. This is the case with the FIFOs in Tegra's AHUB. This new facility can replace SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME. - DMA device This allows requesting DMA channels for a device other than the device which is registering the "PCM" driver. This is quite unusual, but is currently useful on Tegra. In much HW, and in Tegra20, each DAI HW module contains its own FIFOs which DMA writes to. However, in Tegra30, the DMA FIFOs were split out AHUB HW module, which then routes the data through a cross-bar, and into the DAI HW modules. However, the current ASoC driver structure does not expose this detail, and acts as if the FIFOs are still part of the DAI HW modules. Consequently, the "PCM" driver is registered with the DAI HW module, yet the DMA channels must be looked up in the AHUB HW module's device tree node. This new config field allows that to happen. Eventually, the Tegra drivers will be reworked to fully expose the AHUB, and this config field can be removed. Signed-off-by: Stephen Warren Acked-by: Lars-Peter Clausen Signed-off-by: Mark Brown --- include/sound/dmaengine_pcm.h | 6 ++++++ sound/soc/soc-generic-dmaengine-pcm.c | 18 ++++++++++++++++-- 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h index 4ef986cab182..eb73a3a39ec2 100644 --- a/include/sound/dmaengine_pcm.h +++ b/include/sound/dmaengine_pcm.h @@ -114,6 +114,10 @@ void snd_dmaengine_pcm_set_config_from_dai_data( * @compat_filter_fn: Will be used as the filter function when requesting a * channel for platforms which do not use devicetree. The filter parameter * will be the DAI's DMA data. + * @dma_dev: If set, request DMA channel on this device rather than the DAI + * device. + * @chan_names: If set, these custom DMA channel names will be requested at + * registration time. * @pcm_hardware: snd_pcm_hardware struct to be used for the PCM. * @prealloc_buffer_size: Size of the preallocated audio buffer. * @@ -130,6 +134,8 @@ struct snd_dmaengine_pcm_config { struct snd_soc_pcm_runtime *rtd, struct snd_pcm_substream *substream); dma_filter_fn compat_filter_fn; + struct device *dma_dev; + const char *chan_names[SNDRV_PCM_STREAM_LAST + 1]; const struct snd_pcm_hardware *pcm_hardware; unsigned int prealloc_buffer_size; diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index 1cb3494cf278..5b70c556fba3 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -288,7 +288,7 @@ static const char * const dmaengine_pcm_dma_channel_names[] = { }; static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, - struct device *dev) + struct device *dev, const struct snd_dmaengine_pcm_config *config) { unsigned int i; const char *name; @@ -298,12 +298,26 @@ static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, !dev->of_node) return; + if (config->dma_dev) { + /* + * If this warning is seen, it probably means that your Linux + * device structure does not match your HW device structure. + * It would be best to refactor the Linux device structure to + * correctly match the HW structure. + */ + dev_warn(dev, "DMA channels sourced from device %s", + dev_name(config->dma_dev)); + dev = config->dma_dev; + } + for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) { if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) name = "rx-tx"; else name = dmaengine_pcm_dma_channel_names[i]; + if (config->chan_names[i]) + name = config->chan_names[i]; pcm->chan[i] = dma_request_slave_channel(dev, name); if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) break; @@ -346,7 +360,7 @@ int snd_dmaengine_pcm_register(struct device *dev, pcm->config = config; pcm->flags = flags; - dmaengine_pcm_request_chan_of(pcm, dev); + dmaengine_pcm_request_chan_of(pcm, dev, config); if (flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE) ret = snd_soc_add_platform(dev, &pcm->platform, From 0ad7c00057dc1640647c1dc81ccbd009de17a767 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Tue, 26 Nov 2013 10:04:22 -0700 Subject: [PATCH 5/8] dma: add channel request API that supports deferred probe dma_request_slave_channel() simply returns NULL whenever DMA channel lookup fails. Lookup could fail for two distinct reasons: a) No DMA specification exists for the channel name. This includes situations where no DMA specifications exist at all, or other general lookup problems. b) A DMA specification does exist, yet the driver for that channel is not yet registered. Case (b) should trigger deferred probe in client drivers. However, since they have no way to differentiate the two situations, it cannot. Implement new function dma_request_slave_channel_reason(), which performs identically to dma_request_slave_channel(), except that it returns an error-pointer rather than NULL, which allows callers to detect when deferred probe should occur. Eventually, all drivers should be converted to this new API, the old API removed, and the new API renamed to the more desirable name. This patch doesn't convert the existing API and all drivers in one go, since some drivers call dma_request_slave_channel() then dma_request_channel() if that fails. That would require either modifying dma_request_channel() in the same way, or adding extra error-handling code to all affected drivers, and there are close to 100 drivers using the other API, rather than just the 15-20 or so that use dma_request_slave_channel(), which might be tenable in a single patch. acpi_dma_request_slave_chan_by_name() doesn't currently implement deferred probe. It should, but this will be addressed later. Acked-by: Dan Williams Signed-off-by: Stephen Warren Signed-off-by: Vinod Koul --- drivers/dma/dmaengine.c | 35 +++++++++++++++++++++++++++++++---- drivers/dma/of-dma.c | 15 +++++++++------ include/linux/dmaengine.h | 8 ++++++++ 3 files changed, 48 insertions(+), 10 deletions(-) diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index ea806bdc12ef..e17e9b22d85e 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -540,6 +540,8 @@ EXPORT_SYMBOL_GPL(dma_get_slave_channel); * @mask: capabilities that the channel must satisfy * @fn: optional callback to disposition available channels * @fn_param: opaque parameter to pass to dma_filter_fn + * + * Returns pointer to appropriate DMA channel on success or NULL. */ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param) @@ -591,18 +593,43 @@ EXPORT_SYMBOL_GPL(__dma_request_channel); * dma_request_slave_channel - try to allocate an exclusive slave channel * @dev: pointer to client device structure * @name: slave channel name + * + * Returns pointer to appropriate DMA channel on success or an error pointer. */ -struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name) +struct dma_chan *dma_request_slave_channel_reason(struct device *dev, + const char *name) { + struct dma_chan *chan; + /* If device-tree is present get slave info from here */ if (dev->of_node) return of_dma_request_slave_channel(dev->of_node, name); /* If device was enumerated by ACPI get slave info from here */ - if (ACPI_HANDLE(dev)) - return acpi_dma_request_slave_chan_by_name(dev, name); + if (ACPI_HANDLE(dev)) { + chan = acpi_dma_request_slave_chan_by_name(dev, name); + if (chan) + return chan; + } - return NULL; + return ERR_PTR(-ENODEV); +} +EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason); + +/** + * dma_request_slave_channel - try to allocate an exclusive slave channel + * @dev: pointer to client device structure + * @name: slave channel name + * + * Returns pointer to appropriate DMA channel on success or NULL. + */ +struct dma_chan *dma_request_slave_channel(struct device *dev, + const char *name) +{ + struct dma_chan *ch = dma_request_slave_channel_reason(dev, name); + if (IS_ERR(ch)) + return NULL; + return ch; } EXPORT_SYMBOL_GPL(dma_request_slave_channel); diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c index 0b88dd3d05f4..e8fe9dc455f4 100644 --- a/drivers/dma/of-dma.c +++ b/drivers/dma/of-dma.c @@ -143,7 +143,7 @@ static int of_dma_match_channel(struct device_node *np, const char *name, * @np: device node to get DMA request from * @name: name of desired channel * - * Returns pointer to appropriate dma channel on success or NULL on error. + * Returns pointer to appropriate DMA channel on success or an error pointer. */ struct dma_chan *of_dma_request_slave_channel(struct device_node *np, const char *name) @@ -152,17 +152,18 @@ struct dma_chan *of_dma_request_slave_channel(struct device_node *np, struct of_dma *ofdma; struct dma_chan *chan; int count, i; + int ret_no_channel = -ENODEV; if (!np || !name) { pr_err("%s: not enough information provided\n", __func__); - return NULL; + return ERR_PTR(-ENODEV); } count = of_property_count_strings(np, "dma-names"); if (count < 0) { pr_err("%s: dma-names property of node '%s' missing or empty\n", __func__, np->full_name); - return NULL; + return ERR_PTR(-ENODEV); } for (i = 0; i < count; i++) { @@ -172,10 +173,12 @@ struct dma_chan *of_dma_request_slave_channel(struct device_node *np, mutex_lock(&of_dma_lock); ofdma = of_dma_find_controller(&dma_spec); - if (ofdma) + if (ofdma) { chan = ofdma->of_dma_xlate(&dma_spec, ofdma); - else + } else { + ret_no_channel = -EPROBE_DEFER; chan = NULL; + } mutex_unlock(&of_dma_lock); @@ -185,7 +188,7 @@ struct dma_chan *of_dma_request_slave_channel(struct device_node *np, return chan; } - return NULL; + return ERR_PTR(ret_no_channel); } /** diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 41cf0c399288..ed92b30a02fd 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -22,6 +22,7 @@ #define LINUX_DMAENGINE_H #include +#include #include #include #include @@ -1040,6 +1041,8 @@ enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx); void dma_issue_pending_all(void); struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param); +struct dma_chan *dma_request_slave_channel_reason(struct device *dev, + const char *name); struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name); void dma_release_channel(struct dma_chan *chan); #else @@ -1063,6 +1066,11 @@ static inline struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask, { return NULL; } +static inline struct dma_chan *dma_request_slave_channel_reason( + struct device *dev, const char *name) +{ + return ERR_PTR(-ENODEV); +} static inline struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name) { From 5eda87b890f867b098e5566b5543642851e8b9c3 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Tue, 10 Dec 2013 11:11:02 -0700 Subject: [PATCH 6/8] ASoC: dmaengine: support deferred probe for DMA channels Enhance dmaengine_pcm_request_chan_of() to support deferred probe for DMA channels, by using the new dma_request_slave_channel_or_err() API. This prevents snd_dmaengine_pcm_register() from succeeding without acquiring DMA channels due to the relevant DMA controller not yet being registered. Signed-off-by: Stephen Warren Acked-by: Lars-Peter Clausen Signed-off-by: Mark Brown --- sound/soc/soc-generic-dmaengine-pcm.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index 5b70c556fba3..585eaa69e8c3 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -287,16 +287,17 @@ static const char * const dmaengine_pcm_dma_channel_names[] = { [SNDRV_PCM_STREAM_CAPTURE] = "rx", }; -static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, +static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, struct device *dev, const struct snd_dmaengine_pcm_config *config) { unsigned int i; const char *name; + struct dma_chan *chan; if ((pcm->flags & (SND_DMAENGINE_PCM_FLAG_NO_DT | SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME)) || !dev->of_node) - return; + return 0; if (config->dma_dev) { /* @@ -318,13 +319,22 @@ static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, name = dmaengine_pcm_dma_channel_names[i]; if (config->chan_names[i]) name = config->chan_names[i]; - pcm->chan[i] = dma_request_slave_channel(dev, name); + chan = dma_request_slave_channel_reason(dev, name); + if (IS_ERR(chan)) { + if (PTR_ERR(pcm->chan[i]) == -EPROBE_DEFER) + return -EPROBE_DEFER; + pcm->chan[i] = NULL; + } else { + pcm->chan[i] = chan; + } if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) break; } if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) pcm->chan[1] = pcm->chan[0]; + + return 0; } static void dmaengine_pcm_release_chan(struct dmaengine_pcm *pcm) @@ -360,7 +370,9 @@ int snd_dmaengine_pcm_register(struct device *dev, pcm->config = config; pcm->flags = flags; - dmaengine_pcm_request_chan_of(pcm, dev, config); + ret = dmaengine_pcm_request_chan_of(pcm, dev, config); + if (ret) + goto err_free_dma; if (flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE) ret = snd_soc_add_platform(dev, &pcm->platform, From e9036c2a60f368b8ddc349fbbcde918ed32ab597 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Wed, 11 Dec 2013 11:20:50 -0700 Subject: [PATCH 7/8] ASoC: dmaengine: fix deferred probe detection Check the return value of dma_request_slave_channel_reason() to see if deferred probe happens, not the variable the return value will be assigned to later. Reported-by: kbuild test robot Fixes: 5eda87b890f8 ("ASoC: dmaengine: support deferred probe for DMA channels") Signed-off-by: Stephen Warren Signed-off-by: Mark Brown --- sound/soc/soc-generic-dmaengine-pcm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index 585eaa69e8c3..7483922f6ee3 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -321,7 +321,7 @@ static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, name = config->chan_names[i]; chan = dma_request_slave_channel_reason(dev, name); if (IS_ERR(chan)) { - if (PTR_ERR(pcm->chan[i]) == -EPROBE_DEFER) + if (PTR_ERR(chan) == -EPROBE_DEFER) return -EPROBE_DEFER; pcm->chan[i] = NULL; } else { From 2b67f8ba41ac7acf01c8d5c742c713ead8b589cd Mon Sep 17 00:00:00 2001 From: Xiubo Li Date: Tue, 17 Dec 2013 15:16:40 +0800 Subject: [PATCH 8/8] ASoC: dmaengine: Add config parameter NULL check. Because the "ASoC: dmaengine-pcm: Provide default config" has provided us one defualt config of DMA. When using this, the config parameter of devm_snd_dmaengine_pcm_register() will be NULL, so here we need to have a check before using it. Signed-off-by: Xiubo Li Acked-by: Lars-Peter Clausen Signed-off-by: Mark Brown --- sound/soc/soc-generic-dmaengine-pcm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index 7483922f6ee3..2a6c569d991f 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -299,7 +299,7 @@ static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, !dev->of_node) return 0; - if (config->dma_dev) { + if (config && config->dma_dev) { /* * If this warning is seen, it probably means that your Linux * device structure does not match your HW device structure. @@ -317,7 +317,7 @@ static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, name = "rx-tx"; else name = dmaengine_pcm_dma_channel_names[i]; - if (config->chan_names[i]) + if (config && config->chan_names[i]) name = config->chan_names[i]; chan = dma_request_slave_channel_reason(dev, name); if (IS_ERR(chan)) {