On Thu, Jun 4, 2020 at 9:53 AM Nicolas Saenz Julienne
<nsaenzjulienne@xxxxxxx> wrote:
>
> Hi Jim,
>
> On Wed, 2020-06-03 at 15:20 -0400, Jim Quinlan wrote:
> > The new field in struct device 'dma_pfn_offset_map' is used to facilitate
> > the use of multiple pfn offsets between cpu addrs and dma addrs. It
> > subsumes the role of dev->dma_pfn_offset -- a uniform offset -- and
> > designates the single offset a special case.
> >
> > of_dma_configure() is the typical manner to set pfn offsets but there
> > are a number of ad hoc assignments to dev->dma_pfn_offset in the
> > kernel code. These cases now invoke the function
> > attach_uniform_dma_pfn_offset(dev, pfn_offset).
> >
> > Signed-off-by: Jim Quinlan <james.quinlan@xxxxxxxxxxxx>
> > ---
> > arch/arm/include/asm/dma-mapping.h | 9 +-
> > arch/arm/mach-keystone/keystone.c | 9 +-
> > arch/sh/drivers/pci/pcie-sh7786.c | 3 +-
> > arch/sh/kernel/dma-coherent.c | 17 ++--
> > arch/x86/pci/sta2x11-fixup.c | 7 +-
> > drivers/acpi/arm64/iort.c | 5 +-
> > drivers/gpu/drm/sun4i/sun4i_backend.c | 7 +-
> > drivers/iommu/io-pgtable-arm.c | 2 +-
> > .../platform/sunxi/sun4i-csi/sun4i_csi.c | 5 +-
> > .../platform/sunxi/sun6i-csi/sun6i_csi.c | 5 +-
> > drivers/of/address.c | 93 +++++++++++++++++--
> > drivers/of/device.c | 8 +-
> > drivers/remoteproc/remoteproc_core.c | 2 +-
> > .../staging/media/sunxi/cedrus/cedrus_hw.c | 7 +-
> > drivers/usb/core/message.c | 4 +-
> > drivers/usb/core/usb.c | 2 +-
> > include/linux/device.h | 4 +-
> > include/linux/dma-direct.h | 16 +++-
> > include/linux/dma-mapping.h | 45 +++++++++
> > kernel/dma/coherent.c | 11 ++-
> > 20 files changed, 210 insertions(+), 51 deletions(-)
> >
> > diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-
> > mapping.h
> > index bdd80ddbca34..f1e72f99468b 100644
> > --- a/arch/arm/include/asm/dma-mapping.h
> > +++ b/arch/arm/include/asm/dma-mapping.h
> > @@ -35,8 +35,9 @@ static inline const struct dma_map_ops
> > *get_arch_dma_ops(struct bus_type *bus)
> > #ifndef __arch_pfn_to_dma
> > static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn)
> > {
> > - if (dev)
> > - pfn -= dev->dma_pfn_offset;
> > + if (dev && dev->dma_pfn_offset_map)
>
> Would it make sense to move the dev->dma_pfn_offset_map check into
> dma_pfn_offset_from_phys_addr() and return 0 if not available? Same for the
> opposite variant of the function. I think it'd make the code a little simpler on
> some of the use cases, and overall less error prone if anyone starts using the
> function elsewhere.
Yes it makes sense and I was debating doing it but I just wanted to
make it explicit that there was not much cost for this change for the
fastpath -- no dma_pfn_offset whatsoever -- as the cost goes from a
"pfn += dev->dma_pfn_offset" to a "if (dev->dma_pfn_offset_map)". I
will do what you suggest.
>
> > + pfn -= dma_pfn_offset_from_phys_addr(dev, PFN_PHYS(pfn));
> > +
> > return (dma_addr_t)__pfn_to_bus(pfn);
> > }
> >
> > @@ -44,8 +45,8 @@ static inline unsigned long dma_to_pfn(struct device *dev,
> > dma_addr_t addr)
> > {
> > unsigned long pfn = __bus_to_pfn(addr);
> >
> > - if (dev)
> > - pfn += dev->dma_pfn_offset;
> > + if (dev && dev->dma_pfn_offset_map)
> > + pfn += dma_pfn_offset_from_dma_addr(dev, addr);
> >
> > return pfn;
> > }
> > diff --git a/arch/arm/mach-keystone/keystone.c b/arch/arm/mach-
> > keystone/keystone.c
> > index 638808c4e122..e7d3ee6e9cb5 100644
> > --- a/arch/arm/mach-keystone/keystone.c
> > +++ b/arch/arm/mach-keystone/keystone.c
> > @@ -8,6 +8,7 @@
> > */
> > #include <linux/io.h>
> > #include <linux/of.h>
> > +#include <linux/dma-mapping.h>
> > #include <linux/init.h>
> > #include <linux/of_platform.h>
> > #include <linux/of_address.h>
> > @@ -38,9 +39,11 @@ static int keystone_platform_notifier(struct notifier_block
> > *nb,
> > return NOTIFY_BAD;
> >
> > if (!dev->of_node) {
> > - dev->dma_pfn_offset = keystone_dma_pfn_offset;
> > - dev_err(dev, "set dma_pfn_offset%08lx\n",
> > - dev->dma_pfn_offset);
> > + int ret = attach_uniform_dma_pfn_offset
> > + (dev, keystone_dma_pfn_offset);
> > +
> > + dev_err(dev, "set dma_pfn_offset%08lx%s\n",
> > + dev->dma_pfn_offset, ret ? " failed" : "");
> > }
> > return NOTIFY_OK;
> > }
> > diff --git a/arch/sh/drivers/pci/pcie-sh7786.c b/arch/sh/drivers/pci/pcie-
> > sh7786.c
> > index e0b568aaa701..2e832a5c58c1 100644
> > --- a/arch/sh/drivers/pci/pcie-sh7786.c
> > +++ b/arch/sh/drivers/pci/pcie-sh7786.c
> > @@ -12,6 +12,7 @@
> > #include <linux/io.h>
> > #include <linux/async.h>
> > #include <linux/delay.h>
> > +#include <linux/dma-mapping.h>
> > #include <linux/slab.h>
> > #include <linux/clk.h>
> > #include <linux/sh_clk.h>
> > @@ -487,7 +488,7 @@ int pcibios_map_platform_irq(const struct pci_dev *pdev,
> > u8 slot, u8 pin)
> >
> > void pcibios_bus_add_device(struct pci_dev *pdev)
> > {
> > - pdev->dev.dma_pfn_offset = dma_pfn_offset;
> > + attach_uniform_dma_pfn_offset(&pdev->dev, dma_pfn_offset);
> > }
> >
> > static int __init sh7786_pcie_core_init(void)
> > diff --git a/arch/sh/kernel/dma-coherent.c b/arch/sh/kernel/dma-coherent.c
> > index d4811691b93c..5fc9e358b6c7 100644
> > --- a/arch/sh/kernel/dma-coherent.c
> > +++ b/arch/sh/kernel/dma-coherent.c
> > @@ -14,6 +14,8 @@ void *arch_dma_alloc(struct device *dev, size_t size,
> > dma_addr_t *dma_handle,
> > {
> > void *ret, *ret_nocache;
> > int order = get_order(size);
> > + unsigned long pfn;
> > + phys_addr_t phys;
> >
> > gfp |= __GFP_ZERO;
> >
> > @@ -34,11 +36,14 @@ void *arch_dma_alloc(struct device *dev, size_t size,
> > dma_addr_t *dma_handle,
> > return NULL;
> > }
> >
> > - split_page(pfn_to_page(virt_to_phys(ret) >> PAGE_SHIFT), order);
> > + phys = virt_to_phys(ret);
> > + pfn = phys >> PAGE_SHIFT;
>
> nit: not sure it really pays off to have a pfn variable here.
Did it for readability; the compiler's optimization should take care
of any extra variables. But I can switch if you insist.
>
> > + split_page(pfn_to_page(pfn), order);
> >
> > - *dma_handle = virt_to_phys(ret);
> > - if (!WARN_ON(!dev))
> > - *dma_handle -= PFN_PHYS(dev->dma_pfn_offset);
> > + *dma_handle = (dma_addr_t)phys;
> > + if (!WARN_ON(!dev) && dev->dma_pfn_offset_map)
> > + *dma_handle -= PFN_PHYS(
> > + dma_pfn_offset_from_phys_addr(dev, phys));
>
> >
> > return ret_nocache;
> > }
> > @@ -50,8 +55,8 @@ void arch_dma_free(struct device *dev, size_t size, void
> > *vaddr,
> > unsigned long pfn = (dma_handle >> PAGE_SHIFT);
> > int k;
> >
> > - if (!WARN_ON(!dev))
> > - pfn += dev->dma_pfn_offset;
> > + if (!WARN_ON(!dev) && dev->dma_pfn_offset_map)
> > + pfn += dma_pfn_offset_from_dma_addr(dev, dma_handle);
> >
> > for (k = 0; k < (1 << order); k++)
> > __free_pages(pfn_to_page(pfn + k), 0);
> > diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
> > index c313d784efab..4cdeca9f69b6 100644
> > --- a/arch/x86/pci/sta2x11-fixup.c
> > +++ b/arch/x86/pci/sta2x11-fixup.c
> > @@ -12,6 +12,7 @@
> > #include <linux/export.h>
> > #include <linux/list.h>
> > #include <linux/dma-direct.h>
> > +#include <linux/dma-mapping.h>
> > #include <asm/iommu.h>
> >
> > #define STA2X11_SWIOTLB_SIZE (4*1024*1024)
> > @@ -133,7 +134,7 @@ static void sta2x11_map_ep(struct pci_dev *pdev)
> > struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
> > struct device *dev = &pdev->dev;
> > u32 amba_base, max_amba_addr;
> > - int i;
> > + int i, ret;
> >
> > if (!instance)
> > return;
> > @@ -141,7 +142,9 @@ static void sta2x11_map_ep(struct pci_dev *pdev)
> > pci_read_config_dword(pdev, AHB_BASE(0), &amba_base);
> > max_amba_addr = amba_base + STA2X11_AMBA_SIZE - 1;
> >
> > - dev->dma_pfn_offset = PFN_DOWN(-amba_base);
> > + ret = attach_uniform_dma_pfn_offset(dev, PFN_DOWN(-amba_base));
> > + if (ret)
> > + dev_err(dev, "sta2x11: could not set PFN offset\n");
> >
> > dev->bus_dma_limit = max_amba_addr;
> > pci_set_consistent_dma_mask(pdev, max_amba_addr);
> > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> > index 28a6b387e80e..153661ddc74b 100644
> > --- a/drivers/acpi/arm64/iort.c
> > +++ b/drivers/acpi/arm64/iort.c
> > @@ -1142,8 +1142,9 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr,
> > u64 *dma_size)
> > *dma_addr = dmaaddr;
> > *dma_size = size;
> >
> > - dev->dma_pfn_offset = PFN_DOWN(offset);
> > - dev_dbg(dev, "dma_pfn_offset(%#08llx)\n", offset);
> > + ret = attach_uniform_dma_pfn_offset(dev, PFN_DOWN(offset));
> > + dev_dbg(dev, "dma_pfn_offset(%#08llx)%s\n",
> > + offset, ret ? " failed!" : "");
> > }
> >
> > static void __init acpi_iort_register_irq(int hwirq, const char *name,
> > diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c
> > b/drivers/gpu/drm/sun4i/sun4i_backend.c
> > index 072ea113e6be..3d41dfc7d178 100644
> > --- a/drivers/gpu/drm/sun4i/sun4i_backend.c
> > +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
> > @@ -11,6 +11,7 @@
> > #include <linux/module.h>
> > #include <linux/of_device.h>
> > #include <linux/of_graph.h>
> > +#include <linux/dma-mapping.h>
> > #include <linux/platform_device.h>
> > #include <linux/reset.h>
> >
> > @@ -786,7 +787,7 @@ static int sun4i_backend_bind(struct device *dev, struct
> > device *master,
> > const struct sun4i_backend_quirks *quirks;
> > struct resource *res;
> > void __iomem *regs;
> > - int i, ret;
> > + int i, ret = 0;
> >
> > backend = devm_kzalloc(dev, sizeof(*backend), GFP_KERNEL);
> > if (!backend)
> > @@ -812,7 +813,9 @@ static int sun4i_backend_bind(struct device *dev, struct
> > device *master,
> > * on our device since the RAM mapping is at 0 for the DMA bus,
> > * unlike the CPU.
> > */
> > - drm->dev->dma_pfn_offset = PHYS_PFN_OFFSET;
> > + ret = attach_uniform_dma_pfn_offset(dev, PHYS_PFN_OFFSET);
> > + if (ret)
> > + return ret;
> > }
> >
> > backend->engine.node = dev->of_node;
> > diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> > index 04fbd4bf0ff9..e9cc1c2d47cd 100644
> > --- a/drivers/iommu/io-pgtable-arm.c
> > +++ b/drivers/iommu/io-pgtable-arm.c
> > @@ -754,7 +754,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
> > if (cfg->oas > ARM_LPAE_MAX_ADDR_BITS)
> > return NULL;
> >
> > - if (!selftest_running && cfg->iommu_dev->dma_pfn_offset) {
> > + if (!selftest_running && cfg->iommu_dev->dma_pfn_offset_map) {
> > dev_err(cfg->iommu_dev, "Cannot accommodate DMA offset for IOMMU
> > page tables\n");
> > return NULL;
> > }
> > diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> > b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> > index eff34ded6305..7212da5e1076 100644
> > --- a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> > +++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> > @@ -7,6 +7,7 @@
> > */
> >
> > #include <linux/clk.h>
> > +#include <linux/dma-mapping.h>
> > #include <linux/interrupt.h>
> > #include <linux/module.h>
> > #include <linux/mutex.h>
> > @@ -183,7 +184,9 @@ static int sun4i_csi_probe(struct platform_device *pdev)
> > return ret;
> > } else {
> > #ifdef PHYS_PFN_OFFSET
> > - csi->dev->dma_pfn_offset = PHYS_PFN_OFFSET;
> > + ret = attach_uniform_dma_pfn_offset(dev, PHYS_PFN_OFFSET);
> > + if (ret)
> > + return ret;
> > #endif
> > }
> >
> > diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> > b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> > index 055eb0b8e396..2d66d415b6c3 100644
> > --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> > +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> > @@ -898,7 +898,10 @@ static int sun6i_csi_probe(struct platform_device *pdev)
> >
> > sdev->dev = &pdev->dev;
> > /* The DMA bus has the memory mapped at 0 */
> > - sdev->dev->dma_pfn_offset = PHYS_OFFSET >> PAGE_SHIFT;
> > + ret = attach_uniform_dma_pfn_offset(sdev->dev,
> > + PHYS_OFFSET >> PAGE_SHIFT);
> > + if (ret)
> > + return ret;
> >
> > ret = sun6i_csi_resource_request(sdev, pdev);
> > if (ret)
> > diff --git a/drivers/of/address.c b/drivers/of/address.c
> > index 96d8cfb14a60..c89333b0a5fb 100644
> > --- a/drivers/of/address.c
> > +++ b/drivers/of/address.c
> > @@ -918,6 +918,70 @@ void __iomem *of_io_request_and_map(struct device_node
> > *np, int index,
> > }
> > EXPORT_SYMBOL(of_io_request_and_map);
> >
> > +static int attach_dma_pfn_offset_map(struct device *dev,
> > + struct device_node *node, int num_ranges)
>
> As with the previous review, please take this comment with a grain of salt.
>
> I think there should be a clear split between what belongs to OF and what
> belongs to the core device infrastructure.
>
> OF's job should be to parse DT and provide a list/array of ranges, whereas the
> core device infrastructure should provide an API to assign a list of
> ranges/offset to a device.
>
> As a concrete example, you're forcing devices like the sta2x11 to build with OF
> support, which, being an Intel device, it's pretty odd. But I'm also thinking
> of how will all this fit once an ACPI device wants to use it.
To fix this I only have to move attach_uniform_dma_pfn_offset() from
of/address.c to say include/linux/dma-mapping.h. It has no
dependencies on OF. Do you agree?
>
> Expanding on this idea, once you have a split between the OF's and device core
> roles, it transpires that of_dma_get_range()'s job should only be to provide
> the ranges in a device understandable structure and of_dma_configre()'s to
> actually assign the device's parameters. This would obsolete patch #7.
I think you mean patch #8. I agree with you. The reason I needed a
"struct device *" in the call is because I wanted to make sure the
memory that is alloc'd belongs to the device that needs it. If I do a
regular kzalloc(), this memory will become a leak once someone starts
unbinding/binding their device. Also, in all uses of of_dma_rtange()
-- there is only one -- a dev is required as one can't attach an
offset map to NULL.
I do see that there are a number of functions in drivers/of/*.c that
take 'struct device *dev' as an argument so there is precedent for
something like this. Regardless, I need an owner to the memory I
alloc().
>
> > +{
> > + struct of_range_parser parser;
> > + struct of_range range;
> > + struct dma_pfn_offset_region *r;
> > +
> > + r = devm_kcalloc(dev, num_ranges + 1,
> > + sizeof(struct dma_pfn_offset_region), GFP_KERNEL);
> > + if (!r)
> > + return -ENOMEM;
> > + dev->dma_pfn_offset_map = r;
> > + of_dma_range_parser_init(&parser, node);
> > +
> > + /*
> > + * Record all info for DMA ranges array. We could
> > + * just use the of_range struct, but if we did that it
> > + * would require more calculations for phys_to_dma and
> > + * dma_to_phys conversions.
> > + */
> > + for_each_of_range(&parser, &range) {
> > + r->cpu_start = range.cpu_addr;
> > + r->cpu_end = r->cpu_start + range.size - 1;
> > + r->dma_start = range.bus_addr;
> > + r->dma_end = r->dma_start + range.size - 1;
> > + r->pfn_offset = PFN_DOWN(range.cpu_addr)
> > + - PFN_DOWN(range.bus_addr);
> > + r++;
> > + }
> > + return 0;
> > +}
> > +
> > +
> > +
> > +/**
> > + * attach_dma_pfn_offset - Assign scalar offset for all addresses.
> > + * @dev: device pointer; only needed for a corner case.
>
> That's a huge corner :P
Good point; I'm not really sure what percent of Linux configurations
require a dma_pfn_offset. I'll drop the "corner".
>
> > + * @dma_pfn_offset: offset to apply when converting from phys addr
> > + * to dma addr and vice versa.
> > + *
> > + * It returns -ENOMEM if out of memory, otherwise 0.
> > + */
> > +int attach_uniform_dma_pfn_offset(struct device *dev, unsigned long
> > pfn_offset)
>
> As I say above, does this really belong to of/address.c?
No it does not. Will fix.
>
> > +{
> > + struct dma_pfn_offset_region *r;
> > +
> > + if (!dev)
> > + return -ENODEV;
> > +
> > + if (!pfn_offset)
> > + return 0;
> > +
> > + r = devm_kcalloc(dev, 1, sizeof(struct dma_pfn_offset_region),
> > + GFP_KERNEL);
> > + if (!r)
> > + return -ENOMEM;
>
> I think you're missing this:
>
> dev->dma_pfn_offset_map = r;
>
That's a showstopper! DanC also pointed it out but I still didn't see
it. Thanks!
> > +
> > + r->uniform_offset = true;
> > + r->pfn_offset = pfn_offset;
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(attach_uniform_dma_pfn_offset);
> > +
> > /**
> > * of_dma_get_range - Get DMA range info
> > * @dev: device pointer; only needed for a corner case.
> > @@ -933,7 +997,7 @@ EXPORT_SYMBOL(of_io_request_and_map);
> > * CPU addr (phys_addr_t) : pna cells
> > * size : nsize cells
> > *
> > - * It returns -ENODEV if "dma-ranges" property was not found
> > + * It returns -ENODEV if !dev or "dma-ranges" property was not found
> > * for this device in DT.
> > */
> > int of_dma_get_range(struct device *dev, struct device_node *np, u64
> > *dma_addr,
> > @@ -946,7 +1010,13 @@ int of_dma_get_range(struct device *dev, struct
> > device_node *np, u64 *dma_addr,
> > bool found_dma_ranges = false;
> > struct of_range_parser parser;
> > struct of_range range;
> > + phys_addr_t cpu_start = ~(phys_addr_t)0;
> > u64 dma_start = U64_MAX, dma_end = 0, dma_offset = 0;
> > + bool dma_multi_pfn_offset = false;
> > + int num_ranges = 0;
> > +
> > + if (!dev)
> > + return -ENODEV;
>
> Shouldn't this be part of patch #7?
Do you mean #8? Do you mean the test for !dev? It is not required
for #8 so I thought I'd keep these two changes separate. I could
squash them.
>
> Regards,
> Nicolas
>
Many thanks!
Jim Quinlan
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