| Message ID | 20200331183844.30488-3-ulf.hansson@linaro.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | f458488425f1cc9a396aa1d09bb00c48783936da |
| Headers | show |
| Series | amba/platform: Initialize dma_parms at the bus level | expand |
On Tue, Mar 31, 2020 at 8:38 PM Ulf Hansson <ulf.hansson@linaro.org> wrote: > > It's currently the amba driver's responsibility to initialize the pointer, > dma_parms, for its corresponding struct device. The benefit with this > approach allows us to avoid the initialization and to not waste memory for > the struct device_dma_parameters, as this can be decided on a case by case > basis. > > However, it has turned out that this approach is not very practical. Not > only does it lead to open coding, but also to real errors. In principle > callers of dma_set_max_seg_size() doesn't check the error code, but just > assumes it succeeds. > > For these reasons, let's do the initialization from the common amba bus at > the device registration point. This also follows the way the PCI devices > are being managed, see pci_device_add(). > > Suggested-by: Christoph Hellwig <hch@lst.de> > Cc: Russell King <linux@armlinux.org.uk> > Cc: <stable@vger.kernel.org> > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> > --- Reviewed-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index fe1523664816..8558b629880b 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -645,6 +645,7 @@ static void amba_device_initialize(struct amba_device *dev, const char *name) dev->dev.release = amba_device_release; dev->dev.bus = &amba_bustype; dev->dev.dma_mask = &dev->dev.coherent_dma_mask; + dev->dev.dma_parms = &dev->dma_parms; dev->res.name = dev_name(&dev->dev); } diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h index 26f0ecf401ea..0bbfd647f5c6 100644 --- a/include/linux/amba/bus.h +++ b/include/linux/amba/bus.h @@ -65,6 +65,7 @@ struct amba_device { struct device dev; struct resource res; struct clk *pclk; + struct device_dma_parameters dma_parms; unsigned int periphid; unsigned int cid; struct amba_cs_uci_id uci;
It's currently the amba driver's responsibility to initialize the pointer, dma_parms, for its corresponding struct device. The benefit with this approach allows us to avoid the initialization and to not waste memory for the struct device_dma_parameters, as this can be decided on a case by case basis. However, it has turned out that this approach is not very practical. Not only does it lead to open coding, but also to real errors. In principle callers of dma_set_max_seg_size() doesn't check the error code, but just assumes it succeeds. For these reasons, let's do the initialization from the common amba bus at the device registration point. This also follows the way the PCI devices are being managed, see pci_device_add(). Suggested-by: Christoph Hellwig <hch@lst.de> Cc: Russell King <linux@armlinux.org.uk> Cc: <stable@vger.kernel.org> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> --- Changes in v2: - Move initialization to amba_device_initialize() to be more consistent with how we manage platform devices. --- drivers/amba/bus.c | 1 + include/linux/amba/bus.h | 1 + 2 files changed, 2 insertions(+)