| Message ID | 20171013160914.3220-2-niklas.cassel@axis.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
From: Behalf Of Niklas Cassel > Sent: 13 October 2017 17:09 > Since it is a PCIe endpoint device, rather than the CPU, that is supposed > to write to this location, the proper way to get the address to this this > location is really to use the DMA API, rather than virt_to_phys. > > Using virt_to_phys might work on some systems, but by using the DMA API, > we know that it will work on all systems. > > This is essentially the same thing as allocating a buffer in a driver, > to which the endpoint will write to. To do this, we use the DMA API. > > Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> > --- > drivers/pci/dwc/pcie-designware-host.c | 23 ++++++++++++++++------- > drivers/pci/dwc/pcie-designware.h | 3 ++- > 2 files changed, 18 insertions(+), 8 deletions(-) > > diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c > index 81e2157a7cfb..f6d152ea2a03 100644 > --- a/drivers/pci/dwc/pcie-designware-host.c > +++ b/drivers/pci/dwc/pcie-designware-host.c > @@ -83,16 +83,25 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp) > > void dw_pcie_msi_init(struct pcie_port *pp) > { > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + struct device *dev = pci->dev; > + struct page *page; > u64 msi_target; > > - pp->msi_data = __get_free_pages(GFP_KERNEL, 0); > - msi_target = virt_to_phys((void *)pp->msi_data); > + page = alloc_page(GFP_KERNEL | GFP_DMA32); > + pp->msi_data = dma_map_page(dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE); Where are the matching frees? David > + if (dma_mapping_error(dev, pp->msi_data)) { > + dev_err(dev, "failed to map msi data\n"); > + __free_page(page); > + return; > + } > + msi_target = (u64)pp->msi_data; > > /* program the msi_data */ > dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4, > - (u32)(msi_target & 0xffffffff)); > + lower_32_bits(msi_target)); > dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4, > - (u32)(msi_target >> 32 & 0xffffffff)); > + upper_32_bits(msi_target)); > } > > static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq) > @@ -187,10 +196,10 @@ static void dw_msi_setup_msg(struct pcie_port *pp, unsigned int irq, u32 pos) > if (pp->ops->get_msi_addr) > msi_target = pp->ops->get_msi_addr(pp); > else > - msi_target = virt_to_phys((void *)pp->msi_data); > + msi_target = (u64)pp->msi_data; > > - msg.address_lo = (u32)(msi_target & 0xffffffff); > - msg.address_hi = (u32)(msi_target >> 32 & 0xffffffff); > + msg.address_lo = lower_32_bits(msi_target); > + msg.address_hi = upper_32_bits(msi_target); > > if (pp->ops->get_msi_data) > msg.data = pp->ops->get_msi_data(pp, pos); > diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h > index e5d9d77b778e..547352a317f8 100644 > --- a/drivers/pci/dwc/pcie-designware.h > +++ b/drivers/pci/dwc/pcie-designware.h > @@ -17,6 +17,7 @@ > #include <linux/irq.h> > #include <linux/msi.h> > #include <linux/pci.h> > +#include <linux/dma-mapping.h> > > #include <linux/pci-epc.h> > #include <linux/pci-epf.h> > @@ -168,7 +169,7 @@ struct pcie_port { > const struct dw_pcie_host_ops *ops; > int msi_irq; > struct irq_domain *irq_domain; > - unsigned long msi_data; > + dma_addr_t msi_data; > DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS); > }; > > -- > 2.11.0
On Friday, October 13, 2017 12:09 PM, Niklas Cassel wrote: > > Since it is a PCIe endpoint device, rather than the CPU, that is supposed > to write to this location, the proper way to get the address to this this > location is really to use the DMA API, rather than virt_to_phys. > > Using virt_to_phys might work on some systems, but by using the DMA API, > we know that it will work on all systems. > > This is essentially the same thing as allocating a buffer in a driver, > to which the endpoint will write to. To do this, we use the DMA API. I have no objection. However, did you test your patch? In my opinion, your company does not handle DWC PCIe controller, right? If so, you need to get tested-by from other people. Best regards, Jingoo Han > > Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> > --- > drivers/pci/dwc/pcie-designware-host.c | 23 ++++++++++++++++------- > drivers/pci/dwc/pcie-designware.h | 3 ++- > 2 files changed, 18 insertions(+), 8 deletions(-) > > diff --git a/drivers/pci/dwc/pcie-designware-host.c > b/drivers/pci/dwc/pcie-designware-host.c > index 81e2157a7cfb..f6d152ea2a03 100644 > --- a/drivers/pci/dwc/pcie-designware-host.c > +++ b/drivers/pci/dwc/pcie-designware-host.c > @@ -83,16 +83,25 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp) > > void dw_pcie_msi_init(struct pcie_port *pp) > { > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + struct device *dev = pci->dev; > + struct page *page; > u64 msi_target; > > - pp->msi_data = __get_free_pages(GFP_KERNEL, 0); > - msi_target = virt_to_phys((void *)pp->msi_data); > + page = alloc_page(GFP_KERNEL | GFP_DMA32); > + pp->msi_data = dma_map_page(dev, page, 0, PAGE_SIZE, > DMA_FROM_DEVICE); > + if (dma_mapping_error(dev, pp->msi_data)) { > + dev_err(dev, "failed to map msi data\n"); > + __free_page(page); > + return; > + } > + msi_target = (u64)pp->msi_data; > > /* program the msi_data */ > dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4, > - (u32)(msi_target & 0xffffffff)); > + lower_32_bits(msi_target)); > dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4, > - (u32)(msi_target >> 32 & 0xffffffff)); > + upper_32_bits(msi_target)); > } > > static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq) > @@ -187,10 +196,10 @@ static void dw_msi_setup_msg(struct pcie_port *pp, > unsigned int irq, u32 pos) > if (pp->ops->get_msi_addr) > msi_target = pp->ops->get_msi_addr(pp); > else > - msi_target = virt_to_phys((void *)pp->msi_data); > + msi_target = (u64)pp->msi_data; > > - msg.address_lo = (u32)(msi_target & 0xffffffff); > - msg.address_hi = (u32)(msi_target >> 32 & 0xffffffff); > + msg.address_lo = lower_32_bits(msi_target); > + msg.address_hi = upper_32_bits(msi_target); > > if (pp->ops->get_msi_data) > msg.data = pp->ops->get_msi_data(pp, pos); > diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie- > designware.h > index e5d9d77b778e..547352a317f8 100644 > --- a/drivers/pci/dwc/pcie-designware.h > +++ b/drivers/pci/dwc/pcie-designware.h > @@ -17,6 +17,7 @@ > #include <linux/irq.h> > #include <linux/msi.h> > #include <linux/pci.h> > +#include <linux/dma-mapping.h> > > #include <linux/pci-epc.h> > #include <linux/pci-epf.h> > @@ -168,7 +169,7 @@ struct pcie_port { > const struct dw_pcie_host_ops *ops; > int msi_irq; > struct irq_domain *irq_domain; > - unsigned long msi_data; > + dma_addr_t msi_data; > DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS); > }; > > -- > 2.11.0
On Friday, October 13, 2017 12:09 PM, Niklas Cassel wrote: > > Since it is a PCIe endpoint device, rather than the CPU, that is supposed > to write to this location, the proper way to get the address to this this > location is really to use the DMA API, rather than virt_to_phys. > > Using virt_to_phys might work on some systems, but by using the DMA API, > we know that it will work on all systems. > > This is essentially the same thing as allocating a buffer in a driver, > to which the endpoint will write to. To do this, we use the DMA API. > > Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> > --- > drivers/pci/dwc/pcie-designware-host.c | 23 ++++++++++++++++------- > drivers/pci/dwc/pcie-designware.h | 3 ++- > 2 files changed, 18 insertions(+), 8 deletions(-) > > diff --git a/drivers/pci/dwc/pcie-designware-host.c > b/drivers/pci/dwc/pcie-designware-host.c > index 81e2157a7cfb..f6d152ea2a03 100644 > --- a/drivers/pci/dwc/pcie-designware-host.c > +++ b/drivers/pci/dwc/pcie-designware-host.c > @@ -83,16 +83,25 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp) > > void dw_pcie_msi_init(struct pcie_port *pp) > { > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + struct device *dev = pci->dev; > + struct page *page; > u64 msi_target; > > - pp->msi_data = __get_free_pages(GFP_KERNEL, 0); > - msi_target = virt_to_phys((void *)pp->msi_data); > + page = alloc_page(GFP_KERNEL | GFP_DMA32); > + pp->msi_data = dma_map_page(dev, page, 0, PAGE_SIZE, > DMA_FROM_DEVICE); > + if (dma_mapping_error(dev, pp->msi_data)) { > + dev_err(dev, "failed to map msi data\n"); > + __free_page(page); > + return; > + } > + msi_target = (u64)pp->msi_data; > > /* program the msi_data */ > dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4, > - (u32)(msi_target & 0xffffffff)); > + lower_32_bits(msi_target)); > dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4, > - (u32)(msi_target >> 32 & 0xffffffff)); > + upper_32_bits(msi_target)); > } > > static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq) > @@ -187,10 +196,10 @@ static void dw_msi_setup_msg(struct pcie_port *pp, > unsigned int irq, u32 pos) > if (pp->ops->get_msi_addr) > msi_target = pp->ops->get_msi_addr(pp); > else > - msi_target = virt_to_phys((void *)pp->msi_data); > + msi_target = (u64)pp->msi_data; > > - msg.address_lo = (u32)(msi_target & 0xffffffff); > - msg.address_hi = (u32)(msi_target >> 32 & 0xffffffff); > + msg.address_lo = lower_32_bits(msi_target); > + msg.address_hi = upper_32_bits(msi_target); > > if (pp->ops->get_msi_data) > msg.data = pp->ops->get_msi_data(pp, pos); > diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie- > designware.h > index e5d9d77b778e..547352a317f8 100644 > --- a/drivers/pci/dwc/pcie-designware.h > +++ b/drivers/pci/dwc/pcie-designware.h > @@ -17,6 +17,7 @@ > #include <linux/irq.h> > #include <linux/msi.h> > #include <linux/pci.h> > +#include <linux/dma-mapping.h> If possible, please add this header in alphabetical order. Best regards, Jingoo Han > > #include <linux/pci-epc.h> > #include <linux/pci-epf.h> > @@ -168,7 +169,7 @@ struct pcie_port { > const struct dw_pcie_host_ops *ops; > int msi_irq; > struct irq_domain *irq_domain; > - unsigned long msi_data; > + dma_addr_t msi_data; > DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS); > }; > > -- > 2.11.0
On 10/13/2017 06:42 PM, David Laight wrote: > From: Behalf Of Niklas Cassel >> Sent: 13 October 2017 17:09 >> Since it is a PCIe endpoint device, rather than the CPU, that is supposed >> to write to this location, the proper way to get the address to this this >> location is really to use the DMA API, rather than virt_to_phys. >> >> Using virt_to_phys might work on some systems, but by using the DMA API, >> we know that it will work on all systems. >> >> This is essentially the same thing as allocating a buffer in a driver, >> to which the endpoint will write to. To do this, we use the DMA API. >> >> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> >> --- >> drivers/pci/dwc/pcie-designware-host.c | 23 ++++++++++++++++------- >> drivers/pci/dwc/pcie-designware.h | 3 ++- >> 2 files changed, 18 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c >> index 81e2157a7cfb..f6d152ea2a03 100644 >> --- a/drivers/pci/dwc/pcie-designware-host.c >> +++ b/drivers/pci/dwc/pcie-designware-host.c >> @@ -83,16 +83,25 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp) >> >> void dw_pcie_msi_init(struct pcie_port *pp) >> { >> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); >> + struct device *dev = pci->dev; >> + struct page *page; >> u64 msi_target; >> >> - pp->msi_data = __get_free_pages(GFP_KERNEL, 0); >> - msi_target = virt_to_phys((void *)pp->msi_data); >> + page = alloc_page(GFP_KERNEL | GFP_DMA32); >> + pp->msi_data = dma_map_page(dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE); > > Where are the matching frees? Hello David. I couldn't find any matching free_pages call to the __get_free_pages() allocation, so following the same design, I did not add a dma_unmap_page. The current design of most (all?) DWC PCI drivers is that they can only be built-in (i.e. not built as a module), and that they cannot be unbinded (suppress_bind_attrs = true in the platform_driver struct). I will be happy to add a dma_unmap_page (and free_pages), if the maintainer suggests somewhere where I should put it. Regards, Niklas > > David > >> + if (dma_mapping_error(dev, pp->msi_data)) { >> + dev_err(dev, "failed to map msi data\n"); >> + __free_page(page); >> + return; >> + } >> + msi_target = (u64)pp->msi_data; >> >> /* program the msi_data */ >> dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4, >> - (u32)(msi_target & 0xffffffff)); >> + lower_32_bits(msi_target)); >> dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4, >> - (u32)(msi_target >> 32 & 0xffffffff)); >> + upper_32_bits(msi_target)); >> } >> >> static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq) >> @@ -187,10 +196,10 @@ static void dw_msi_setup_msg(struct pcie_port *pp, unsigned int irq, u32 pos) >> if (pp->ops->get_msi_addr) >> msi_target = pp->ops->get_msi_addr(pp); >> else >> - msi_target = virt_to_phys((void *)pp->msi_data); >> + msi_target = (u64)pp->msi_data; >> >> - msg.address_lo = (u32)(msi_target & 0xffffffff); >> - msg.address_hi = (u32)(msi_target >> 32 & 0xffffffff); >> + msg.address_lo = lower_32_bits(msi_target); >> + msg.address_hi = upper_32_bits(msi_target); >> >> if (pp->ops->get_msi_data) >> msg.data = pp->ops->get_msi_data(pp, pos); >> diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h >> index e5d9d77b778e..547352a317f8 100644 >> --- a/drivers/pci/dwc/pcie-designware.h >> +++ b/drivers/pci/dwc/pcie-designware.h >> @@ -17,6 +17,7 @@ >> #include <linux/irq.h> >> #include <linux/msi.h> >> #include <linux/pci.h> >> +#include <linux/dma-mapping.h> >> >> #include <linux/pci-epc.h> >> #include <linux/pci-epf.h> >> @@ -168,7 +169,7 @@ struct pcie_port { >> const struct dw_pcie_host_ops *ops; >> int msi_irq; >> struct irq_domain *irq_domain; >> - unsigned long msi_data; >> + dma_addr_t msi_data; >> DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS); >> }; >> >> -- >> 2.11.0 >
On 10/13/2017 06:43 PM, Jingoo Han wrote: > On Friday, October 13, 2017 12:09 PM, Niklas Cassel wrote: >> >> Since it is a PCIe endpoint device, rather than the CPU, that is supposed >> to write to this location, the proper way to get the address to this this >> location is really to use the DMA API, rather than virt_to_phys. >> >> Using virt_to_phys might work on some systems, but by using the DMA API, >> we know that it will work on all systems. >> >> This is essentially the same thing as allocating a buffer in a driver, >> to which the endpoint will write to. To do this, we use the DMA API. > Hello Jingoo. > I have no objection. However, did you test your patch? I've tested the patch on the ARTPEC-6 and the ARTPEC-7 SoC, one which has a 64-bit dma_addr_t, one which has a 32-bit dma_addr_t. However, since device drivers use dma_map_page all the time, for this exact purpose, I don't think there should be a problem. (Famous last words..) > In my opinion, your company does not handle DWC PCIe controller, right? Right, we are not Synopsys ;) > If so, you need to get tested-by from other people. I agree, a couple of Tested-by would be a good idea. Joao and Kishon, if you have the time, could you please help me out and see MSI still works on your platform with this patch? Regards, Niklas > > Best regards, > Jingoo Han > >> >> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> >> --- >> drivers/pci/dwc/pcie-designware-host.c | 23 ++++++++++++++++------- >> drivers/pci/dwc/pcie-designware.h | 3 ++- >> 2 files changed, 18 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/pci/dwc/pcie-designware-host.c >> b/drivers/pci/dwc/pcie-designware-host.c >> index 81e2157a7cfb..f6d152ea2a03 100644 >> --- a/drivers/pci/dwc/pcie-designware-host.c >> +++ b/drivers/pci/dwc/pcie-designware-host.c >> @@ -83,16 +83,25 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp) >> >> void dw_pcie_msi_init(struct pcie_port *pp) >> { >> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); >> + struct device *dev = pci->dev; >> + struct page *page; >> u64 msi_target; >> >> - pp->msi_data = __get_free_pages(GFP_KERNEL, 0); >> - msi_target = virt_to_phys((void *)pp->msi_data); >> + page = alloc_page(GFP_KERNEL | GFP_DMA32); >> + pp->msi_data = dma_map_page(dev, page, 0, PAGE_SIZE, >> DMA_FROM_DEVICE); >> + if (dma_mapping_error(dev, pp->msi_data)) { >> + dev_err(dev, "failed to map msi data\n"); >> + __free_page(page); >> + return; >> + } >> + msi_target = (u64)pp->msi_data; >> >> /* program the msi_data */ >> dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4, >> - (u32)(msi_target & 0xffffffff)); >> + lower_32_bits(msi_target)); >> dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4, >> - (u32)(msi_target >> 32 & 0xffffffff)); >> + upper_32_bits(msi_target)); >> } >> >> static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq) >> @@ -187,10 +196,10 @@ static void dw_msi_setup_msg(struct pcie_port *pp, >> unsigned int irq, u32 pos) >> if (pp->ops->get_msi_addr) >> msi_target = pp->ops->get_msi_addr(pp); >> else >> - msi_target = virt_to_phys((void *)pp->msi_data); >> + msi_target = (u64)pp->msi_data; >> >> - msg.address_lo = (u32)(msi_target & 0xffffffff); >> - msg.address_hi = (u32)(msi_target >> 32 & 0xffffffff); >> + msg.address_lo = lower_32_bits(msi_target); >> + msg.address_hi = upper_32_bits(msi_target); >> >> if (pp->ops->get_msi_data) >> msg.data = pp->ops->get_msi_data(pp, pos); >> diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie- >> designware.h >> index e5d9d77b778e..547352a317f8 100644 >> --- a/drivers/pci/dwc/pcie-designware.h >> +++ b/drivers/pci/dwc/pcie-designware.h >> @@ -17,6 +17,7 @@ >> #include <linux/irq.h> >> #include <linux/msi.h> >> #include <linux/pci.h> >> +#include <linux/dma-mapping.h> >> >> #include <linux/pci-epc.h> >> #include <linux/pci-epf.h> >> @@ -168,7 +169,7 @@ struct pcie_port { >> const struct dw_pcie_host_ops *ops; >> int msi_irq; >> struct irq_domain *irq_domain; >> - unsigned long msi_data; >> + dma_addr_t msi_data; >> DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS); >> }; >> >> -- >> 2.11.0 > >
On 10/13/2017 06:47 PM, Jingoo Han wrote: > On Friday, October 13, 2017 12:09 PM, Niklas Cassel wrote: >> >> Since it is a PCIe endpoint device, rather than the CPU, that is supposed >> to write to this location, the proper way to get the address to this this >> location is really to use the DMA API, rather than virt_to_phys. >> >> Using virt_to_phys might work on some systems, but by using the DMA API, >> we know that it will work on all systems. >> >> This is essentially the same thing as allocating a buffer in a driver, >> to which the endpoint will write to. To do this, we use the DMA API. >> >> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> >> --- >> drivers/pci/dwc/pcie-designware-host.c | 23 ++++++++++++++++------- >> drivers/pci/dwc/pcie-designware.h | 3 ++- >> 2 files changed, 18 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/pci/dwc/pcie-designware-host.c >> b/drivers/pci/dwc/pcie-designware-host.c >> index 81e2157a7cfb..f6d152ea2a03 100644 >> --- a/drivers/pci/dwc/pcie-designware-host.c >> +++ b/drivers/pci/dwc/pcie-designware-host.c >> @@ -83,16 +83,25 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp) >> >> void dw_pcie_msi_init(struct pcie_port *pp) >> { >> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); >> + struct device *dev = pci->dev; >> + struct page *page; >> u64 msi_target; >> >> - pp->msi_data = __get_free_pages(GFP_KERNEL, 0); >> - msi_target = virt_to_phys((void *)pp->msi_data); >> + page = alloc_page(GFP_KERNEL | GFP_DMA32); >> + pp->msi_data = dma_map_page(dev, page, 0, PAGE_SIZE, >> DMA_FROM_DEVICE); >> + if (dma_mapping_error(dev, pp->msi_data)) { >> + dev_err(dev, "failed to map msi data\n"); >> + __free_page(page); >> + return; >> + } >> + msi_target = (u64)pp->msi_data; >> >> /* program the msi_data */ >> dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4, >> - (u32)(msi_target & 0xffffffff)); >> + lower_32_bits(msi_target)); >> dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4, >> - (u32)(msi_target >> 32 & 0xffffffff)); >> + upper_32_bits(msi_target)); >> } >> >> static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq) >> @@ -187,10 +196,10 @@ static void dw_msi_setup_msg(struct pcie_port *pp, >> unsigned int irq, u32 pos) >> if (pp->ops->get_msi_addr) >> msi_target = pp->ops->get_msi_addr(pp); >> else >> - msi_target = virt_to_phys((void *)pp->msi_data); >> + msi_target = (u64)pp->msi_data; >> >> - msg.address_lo = (u32)(msi_target & 0xffffffff); >> - msg.address_hi = (u32)(msi_target >> 32 & 0xffffffff); >> + msg.address_lo = lower_32_bits(msi_target); >> + msg.address_hi = upper_32_bits(msi_target); >> >> if (pp->ops->get_msi_data) >> msg.data = pp->ops->get_msi_data(pp, pos); >> diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie- >> designware.h >> index e5d9d77b778e..547352a317f8 100644 >> --- a/drivers/pci/dwc/pcie-designware.h >> +++ b/drivers/pci/dwc/pcie-designware.h >> @@ -17,6 +17,7 @@ >> #include <linux/irq.h> >> #include <linux/msi.h> >> #include <linux/pci.h> >> +#include <linux/dma-mapping.h> > > If possible, please add this header in alphabetical order. Absolutely, I will send a V2 series as soon as I get some review comments on any of the other patches in the series. Regards, Niklas > > Best regards, > Jingoo Han > >> >> #include <linux/pci-epc.h> >> #include <linux/pci-epf.h> >> @@ -168,7 +169,7 @@ struct pcie_port { >> const struct dw_pcie_host_ops *ops; >> int msi_irq; >> struct irq_domain *irq_domain; >> - unsigned long msi_data; >> + dma_addr_t msi_data; >> DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS); >> }; >> >> -- >> 2.11.0 > >
On Fri, Oct 13, 2017 at 06:09:04PM +0200, Niklas Cassel wrote: > Since it is a PCIe endpoint device, rather than the CPU, that is supposed > to write to this location, the proper way to get the address to this this > location is really to use the DMA API, rather than virt_to_phys. > > Using virt_to_phys might work on some systems, but by using the DMA API, > we know that it will work on all systems. virt_to_phys() is definitely deprecated for this case. > This is essentially the same thing as allocating a buffer in a driver, > to which the endpoint will write to. To do this, we use the DMA API. > > Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> > --- > drivers/pci/dwc/pcie-designware-host.c | 23 ++++++++++++++++------- > drivers/pci/dwc/pcie-designware.h | 3 ++- > 2 files changed, 18 insertions(+), 8 deletions(-) > > diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c > index 81e2157a7cfb..f6d152ea2a03 100644 > --- a/drivers/pci/dwc/pcie-designware-host.c > +++ b/drivers/pci/dwc/pcie-designware-host.c > @@ -83,16 +83,25 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp) > > void dw_pcie_msi_init(struct pcie_port *pp) > { > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > + struct device *dev = pci->dev; > + struct page *page; > u64 msi_target; > > - pp->msi_data = __get_free_pages(GFP_KERNEL, 0); > - msi_target = virt_to_phys((void *)pp->msi_data); > + page = alloc_page(GFP_KERNEL | GFP_DMA32); > + pp->msi_data = dma_map_page(dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE); > + if (dma_mapping_error(dev, pp->msi_data)) { > + dev_err(dev, "failed to map msi data\n"); s/msi/MSI/ since it's English text. > + __free_page(page); > + return; > + } > + msi_target = (u64)pp->msi_data; > > /* program the msi_data */ > dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4, > - (u32)(msi_target & 0xffffffff)); > + lower_32_bits(msi_target)); > dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4, > - (u32)(msi_target >> 32 & 0xffffffff)); > + upper_32_bits(msi_target)); These are cleanups unrelated to the DMA change, right? I think they're fine, but should be in a different patch. It looks like there are a few more occurrences of this pattern in drivers/pci that could be changed. > } > > static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq) > @@ -187,10 +196,10 @@ static void dw_msi_setup_msg(struct pcie_port *pp, unsigned int irq, u32 pos) > if (pp->ops->get_msi_addr) > msi_target = pp->ops->get_msi_addr(pp); > else > - msi_target = virt_to_phys((void *)pp->msi_data); > + msi_target = (u64)pp->msi_data; > > - msg.address_lo = (u32)(msi_target & 0xffffffff); > - msg.address_hi = (u32)(msi_target >> 32 & 0xffffffff); > + msg.address_lo = lower_32_bits(msi_target); > + msg.address_hi = upper_32_bits(msi_target); > > if (pp->ops->get_msi_data) > msg.data = pp->ops->get_msi_data(pp, pos); > diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h > index e5d9d77b778e..547352a317f8 100644 > --- a/drivers/pci/dwc/pcie-designware.h > +++ b/drivers/pci/dwc/pcie-designware.h > @@ -17,6 +17,7 @@ > #include <linux/irq.h> > #include <linux/msi.h> > #include <linux/pci.h> > +#include <linux/dma-mapping.h> > > #include <linux/pci-epc.h> > #include <linux/pci-epf.h> > @@ -168,7 +169,7 @@ struct pcie_port { > const struct dw_pcie_host_ops *ops; > int msi_irq; > struct irq_domain *irq_domain; > - unsigned long msi_data; > + dma_addr_t msi_data; > DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS); > }; > > -- > 2.11.0 >
diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c index 81e2157a7cfb..f6d152ea2a03 100644 --- a/drivers/pci/dwc/pcie-designware-host.c +++ b/drivers/pci/dwc/pcie-designware-host.c @@ -83,16 +83,25 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp) void dw_pcie_msi_init(struct pcie_port *pp) { + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); + struct device *dev = pci->dev; + struct page *page; u64 msi_target; - pp->msi_data = __get_free_pages(GFP_KERNEL, 0); - msi_target = virt_to_phys((void *)pp->msi_data); + page = alloc_page(GFP_KERNEL | GFP_DMA32); + pp->msi_data = dma_map_page(dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE); + if (dma_mapping_error(dev, pp->msi_data)) { + dev_err(dev, "failed to map msi data\n"); + __free_page(page); + return; + } + msi_target = (u64)pp->msi_data; /* program the msi_data */ dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4, - (u32)(msi_target & 0xffffffff)); + lower_32_bits(msi_target)); dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4, - (u32)(msi_target >> 32 & 0xffffffff)); + upper_32_bits(msi_target)); } static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq) @@ -187,10 +196,10 @@ static void dw_msi_setup_msg(struct pcie_port *pp, unsigned int irq, u32 pos) if (pp->ops->get_msi_addr) msi_target = pp->ops->get_msi_addr(pp); else - msi_target = virt_to_phys((void *)pp->msi_data); + msi_target = (u64)pp->msi_data; - msg.address_lo = (u32)(msi_target & 0xffffffff); - msg.address_hi = (u32)(msi_target >> 32 & 0xffffffff); + msg.address_lo = lower_32_bits(msi_target); + msg.address_hi = upper_32_bits(msi_target); if (pp->ops->get_msi_data) msg.data = pp->ops->get_msi_data(pp, pos); diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h index e5d9d77b778e..547352a317f8 100644 --- a/drivers/pci/dwc/pcie-designware.h +++ b/drivers/pci/dwc/pcie-designware.h @@ -17,6 +17,7 @@ #include <linux/irq.h> #include <linux/msi.h> #include <linux/pci.h> +#include <linux/dma-mapping.h> #include <linux/pci-epc.h> #include <linux/pci-epf.h> @@ -168,7 +169,7 @@ struct pcie_port { const struct dw_pcie_host_ops *ops; int msi_irq; struct irq_domain *irq_domain; - unsigned long msi_data; + dma_addr_t msi_data; DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS); };
Since it is a PCIe endpoint device, rather than the CPU, that is supposed to write to this location, the proper way to get the address to this this location is really to use the DMA API, rather than virt_to_phys. Using virt_to_phys might work on some systems, but by using the DMA API, we know that it will work on all systems. This is essentially the same thing as allocating a buffer in a driver, to which the endpoint will write to. To do this, we use the DMA API. Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> --- drivers/pci/dwc/pcie-designware-host.c | 23 ++++++++++++++++------- drivers/pci/dwc/pcie-designware.h | 3 ++- 2 files changed, 18 insertions(+), 8 deletions(-)