[PATCH 5/8] drivers: platform: Configure dma operations at probe time
From: laurent.pinchart@ideasonboard.com (Laurent Pinchart)
Date: 2016-08-16 09:25:02
Also in:
linux-iommu
Hi Sricharan, Thank you for the patch. On Tuesday 09 Aug 2016 04:19:07 Sricharan R wrote:
quoted hunk ↗ jump to hunk
Configuring DMA ops at probe time will allow deferring device probe when the IOMMU isn't available yet. Signed-off-by: Sricharan R <redacted> --- drivers/base/dd.c | 11 +++++++++++ drivers/base/dma-mapping.c | 11 +++++++++++ include/linux/dma-mapping.h | 3 +++ 3 files changed, 25 insertions(+)diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 16688f5..b9978af 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c@@ -19,6 +19,7 @@ #include <linux/device.h> #include <linux/delay.h> +#include <linux/dma-mapping.h> #include <linux/module.h> #include <linux/kthread.h> #include <linux/wait.h>@@ -353,6 +354,10 @@ static int really_probe(struct device *dev, structdevice_driver *drv) if (ret) goto pinctrl_bind_failed; + ret = dma_configure_ops(dev);
Your patch doesn't remove the of_dma_configure_ops() from
of_platform_device_create_pdata(). Unless I'm mistaken, you will then end up
configuring the DMA ops twice, which at least on ARM will be a no-op the
second time:
(arch_setup_dma_ops)
/*
* Don't override the dma_ops if they have already been set. Ideally
* this should be the only location where dma_ops are set, remove this
* check when all other callers of set_dma_ops will have disappeared.
*/
if (dev->archdata.dma_ops)
return;
For the same reason I'm wondering whether you shouldn't also remove the
of_dma_configure_ops() call from of_amba_device_create() (I don't remember why
I left it there in my original patch series).
quoted hunk ↗ jump to hunk
+ if (ret) + goto dma_failed; + if (driver_sysfs_add(dev)) { printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", __func__, dev_name(dev));@@ -394,7 +399,10 @@ static int really_probe(struct device *dev, structdevice_driver *drv) drv->bus->name, __func__, dev_name(dev), drv->name); goto done; + probe_failed: + dma_deconfigure(dev); +dma_failed: if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_DRIVER_NOT_BOUND,
dev);
quoted hunk ↗ jump to hunk
@@ -780,6 +788,9 @@ static void __device_release_driver(struct device *dev) dev->bus->remove(dev); else if (drv->remove) drv->remove(dev); + + dma_deconfigure(dev); + devres_release_all(dev); dev->driver = NULL; dev_set_drvdata(dev, NULL);diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c index d799662..ccc1c6e 100644 --- a/drivers/base/dma-mapping.c +++ b/drivers/base/dma-mapping.c@@ -10,6 +10,7 @@ #include <linux/dma-mapping.h> #include <linux/export.h> #include <linux/gfp.h> +#include <linux/of_device.h> #include <linux/slab.h> #include <linux/vmalloc.h>@@ -166,6 +167,16 @@ void dmam_free_noncoherent(struct device *dev, size_tsize, void *vaddr, } EXPORT_SYMBOL(dmam_free_noncoherent); +int dma_configure_ops(struct device *dev) +{ + return of_dma_configure_ops(dev, dev->of_node); +} + +void dma_deconfigure(struct device *dev) +{ + of_dma_deconfigure(dev); +} + #ifdef CONFIG_HAVE_GENERIC_DMA_COHERENT static void dmam_coherent_decl_release(struct device *dev, void *res)diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 71c1b21..a49aac9 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h@@ -613,6 +613,9 @@ dma_mark_declared_memory_occupied(struct device *dev, } #endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */ +int dma_configure_ops(struct device *dev); +void dma_deconfigure(struct device *dev); + /* * Managed DMA API */
-- Regards, Laurent Pinchart