Re: [PATCH 5/7 v5] bus: fsl-mc: support dma configure for devices on fsl-mc bus

From: Robin Murphy
Date: Tue Jul 03 2018 - 12:14:16 EST


On 20/05/18 14:49, Nipun Gupta wrote:
This patch adds support of dma configuration for devices on fsl-mc
bus using 'dma_configure' callback for busses. Also, directly calling
arch_setup_dma_ops is removed from the fsl-mc bus.

Looks like this is the final arch_setup_dma_ops offender, yay!

Signed-off-by: Nipun Gupta <nipun.gupta@xxxxxxx>
Reviewed-by: Laurentiu Tudor <laurentiu.tudor@xxxxxxx>
---
drivers/bus/fsl-mc/fsl-mc-bus.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
index 5d8266c..fa43c7d 100644
--- a/drivers/bus/fsl-mc/fsl-mc-bus.c
+++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
@@ -127,6 +127,16 @@ static int fsl_mc_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
return 0;
}
+static int fsl_mc_dma_configure(struct device *dev)
+{
+ struct device *dma_dev = dev;
+
+ while (dev_is_fsl_mc(dma_dev))
+ dma_dev = dma_dev->parent;
+
+ return of_dma_configure(dev, dma_dev->of_node, 0);
+}
+
static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
@@ -148,6 +158,7 @@ struct bus_type fsl_mc_bus_type = {
.name = "fsl-mc",
.match = fsl_mc_bus_match,
.uevent = fsl_mc_bus_uevent,
+ .dma_configure = fsl_mc_dma_configure,
.dev_groups = fsl_mc_dev_groups,
};
EXPORT_SYMBOL_GPL(fsl_mc_bus_type);
@@ -633,10 +644,6 @@ int fsl_mc_device_add(struct fsl_mc_obj_desc *obj_desc,
goto error_cleanup_dev;
}
- /* Objects are coherent, unless 'no shareability' flag set. */
- if (!(obj_desc->flags & FSL_MC_OBJ_FLAG_NO_MEM_SHAREABILITY))

Although it seems we do end up without any handling of this "non-coherent object behind coherent MC" case, and I'm not sure how easily that could be accommodated by generic code... :/ How important is the quirk?

Robin.

- arch_setup_dma_ops(&mc_dev->dev, 0, 0, NULL, true);
-
/*
* The device-specific probe callback will get invoked by device_add()
*/