| Message ID | 20200325113407.26996-3-ulf.hansson@linaro.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | amba/platform: Initialize dma_parms at the bus level | expand |
Le 3/25/20 à 12:34 PM, Ulf Hansson a écrit : > 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(). > tested with mmc: mmci_sdmmc fix Tested-by: Ludovic Barre <ludovic.barre@st.com> > 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> > --- > drivers/amba/bus.c | 2 ++ > include/linux/amba/bus.h | 1 + > 2 files changed, 3 insertions(+) > > diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c > index fe1523664816..5e61783ce92d 100644 > --- a/drivers/amba/bus.c > +++ b/drivers/amba/bus.c > @@ -374,6 +374,8 @@ static int amba_device_try_add(struct amba_device *dev, struct resource *parent) > WARN_ON(dev->irq[0] == (unsigned int)-1); > WARN_ON(dev->irq[1] == (unsigned int)-1); > > + dev->dev.dma_parms = &dev->dma_parms; > + > ret = request_resource(parent, &dev->res); > if (ret) > goto err_out; > 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; >
On Wed, Mar 25, 2020 at 12:34 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: Linus Walleij <linus.walleij@linaro.org> Yours, Linus Walleij
On Wed, Mar 25, 2020 at 12:34 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> Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index fe1523664816..5e61783ce92d 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -374,6 +374,8 @@ static int amba_device_try_add(struct amba_device *dev, struct resource *parent) WARN_ON(dev->irq[0] == (unsigned int)-1); WARN_ON(dev->irq[1] == (unsigned int)-1); + dev->dev.dma_parms = &dev->dma_parms; + ret = request_resource(parent, &dev->res); if (ret) goto err_out; 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> --- drivers/amba/bus.c | 2 ++ include/linux/amba/bus.h | 1 + 2 files changed, 3 insertions(+)