Re: [PATCH v2 09/14] device core: Add ability to handle multiple dma offsets

From: Andy Shevchenko
Date: Tue May 26 2020 - 16:55:11 EST

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In reply to: Jim Quinlan: "[PATCH v2 09/14] device core: Add ability to handle multiple dma offsets"
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On Tue, May 26, 2020 at 03:12:48PM -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 is
> similar to 'dma_pfn_offset' except that the offset chosen depends on the
> cpu or dma address involved.
>
> Signed-off-by: Jim Quinlan <james.quinlan@xxxxxxxxxxxx>
> ---
> drivers/of/address.c | 65 +++++++++++++++++++++++++++++++++++--
> drivers/usb/core/message.c | 3 ++
> drivers/usb/core/usb.c | 3 ++
> include/linux/device.h | 10 +++++-
> include/linux/dma-direct.h | 10 ++++--
> include/linux/dma-mapping.h | 46 ++++++++++++++++++++++++++
> kernel/dma/Kconfig | 13 ++++++++
> 7 files changed, 144 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 96d8cfb14a60..a01afffcde7d 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -918,6 +918,47 @@ void __iomem *of_io_request_and_map(struct device_node *np, int index,
> }
> EXPORT_SYMBOL(of_io_request_and_map);
>
> +#ifdef CONFIG_DMA_PFN_OFFSET_MAP
> +static int attach_dma_pfn_offset_map(struct device *dev,
> + struct device_node *node, int num_ranges)
> +{
> + struct of_range_parser parser;
> + struct of_range range;
> + size_t r_size = (num_ranges + 1)
> + * sizeof(struct dma_pfn_offset_region);
> + struct dma_pfn_offset_region *r;
> +

> + r = devm_kzalloc(dev, r_size, GFP_KERNEL);

devm_?!

Looking at r_size it should be rather kcalloc().

> + 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_beg = range.cpu_addr;
> + r->cpu_end = r->cpu_beg + range.size;
> + r->dma_beg = range.bus_addr;
> + r->dma_end = r->dma_beg + range.size;
> + r->pfn_offset = PFN_DOWN(range.cpu_addr)
> + - PFN_DOWN(range.bus_addr);
> + r++;
> + }
> + return 0;
> +}
> +#else
> +static int attach_dma_pfn_offset_map(struct device *dev,
> + struct device_node *node, int num_ranges)
> +{
> + return 0;
> +}
> +#endif
> +
> /**
> * of_dma_get_range - Get DMA range info
> * @dev: device pointer; only needed for a corner case.
> @@ -947,6 +988,8 @@ int of_dma_get_range(struct device *dev, struct device_node *np, u64 *dma_addr,
> struct of_range_parser parser;
> struct of_range range;
> u64 dma_start = U64_MAX, dma_end = 0, dma_offset = 0;
> + bool dma_multi_pfn_offset = false;
> + int num_ranges = 0;
>
> while (node) {
> ranges = of_get_property(node, "dma-ranges", &len);
> @@ -977,10 +1020,19 @@ int of_dma_get_range(struct device *dev, struct device_node *np, u64 *dma_addr,
> pr_debug("dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",
> range.bus_addr, range.cpu_addr, range.size);
>
> + num_ranges++;
> if (dma_offset && range.cpu_addr - range.bus_addr != dma_offset) {
> - pr_warn("Can't handle multiple dma-ranges with different offsets on node(%pOF)\n", node);
> - /* Don't error out as we'd break some existing DTs */
> - continue;
> + if (!IS_ENABLED(CONFIG_DMA_PFN_OFFSET_MAP)) {
> + pr_warn("Can't handle multiple dma-ranges with different offsets on node(%pOF)\n", node);
> + pr_warn("Perhaps set DMA_PFN_OFFSET_MAP=y?\n");
> + /*
> + * Don't error out as we'd break some existing
> + * DTs that are using configs w/o
> + * CONFIG_DMA_PFN_OFFSET_MAP set.
> + */
> + continue;
> + }
> + dma_multi_pfn_offset = true;
> }
> dma_offset = range.cpu_addr - range.bus_addr;
>
> @@ -991,6 +1043,13 @@ int of_dma_get_range(struct device *dev, struct device_node *np, u64 *dma_addr,
> dma_end = range.bus_addr + range.size;
> }
>
> + if (dma_multi_pfn_offset) {
> + dma_offset = 0;
> + ret = attach_dma_pfn_offset_map(dev, node, num_ranges);
> + if (ret)
> + return ret;
> + }
> +
> if (dma_start >= dma_end) {
> ret = -EINVAL;
> pr_debug("Invalid DMA ranges configuration on node(%pOF)\n",
> diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
> index 6197938dcc2d..aaa3e58f5eb4 100644
> --- a/drivers/usb/core/message.c
> +++ b/drivers/usb/core/message.c
> @@ -1960,6 +1960,9 @@ int usb_set_configuration(struct usb_device *dev, int configuration)
> */
> intf->dev.dma_mask = dev->dev.dma_mask;
> intf->dev.dma_pfn_offset = dev->dev.dma_pfn_offset;
> +#ifdef CONFIG_DMA_PFN_OFFSET_MAP
> + intf->dev.dma_pfn_offset_map = dev->dev.dma_pfn_offset_map;
> +#endif
> INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
> intf->minor = -1;
> device_initialize(&intf->dev);
> diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
> index f16c26dc079d..d2ed4d90e56e 100644
> --- a/drivers/usb/core/usb.c
> +++ b/drivers/usb/core/usb.c
> @@ -612,6 +612,9 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
> */
> dev->dev.dma_mask = bus->sysdev->dma_mask;
> dev->dev.dma_pfn_offset = bus->sysdev->dma_pfn_offset;
> +#ifdef CONFIG_DMA_PFN_OFFSET_MAP
> + dev->dev.dma_pfn_offset_map = bus->sysdev->dma_pfn_offset_map;
> +#endif
> set_dev_node(&dev->dev, dev_to_node(bus->sysdev));
> dev->state = USB_STATE_ATTACHED;
> dev->lpm_disable_count = 1;
> diff --git a/include/linux/device.h b/include/linux/device.h
> index ac8e37cd716a..67a240ad4fc5 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -493,6 +493,8 @@ struct dev_links_info {
> * @bus_dma_limit: Limit of an upstream bridge or bus which imposes a smaller
> * DMA limit than the device itself supports.
> * @dma_pfn_offset: offset of DMA memory range relatively of RAM
> + * @dma_pfn_offset_map: Like dma_pfn_offset but used when there are multiple
> + * pfn offsets for multiple dma-ranges.
> * @dma_parms: A low level driver may set these to teach IOMMU code about
> * segment limitations.
> * @dma_pools: Dma pools (if dma'ble device).
> @@ -578,7 +580,13 @@ struct device {
> allocations such descriptors. */
> u64 bus_dma_limit; /* upstream dma constraint */
> unsigned long dma_pfn_offset;
> -
> +#ifdef CONFIG_DMA_PFN_OFFSET_MAP
> + const struct dma_pfn_offset_region *dma_pfn_offset_map;

> + /* Like dma_pfn_offset, but for
> + * the unlikely case of multiple
> + * offsets. If non-null, dma_pfn_offset
> + * will be set to 0. */

A bit harder to read comment indented too much and located after the declared variable.

> +#endif
> struct device_dma_parameters *dma_parms;
>
> struct list_head dma_pools; /* dma pools (if dma'ble) */
> diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
> index 24b8684aa21d..03110a57eabc 100644
> --- a/include/linux/dma-direct.h
> +++ b/include/linux/dma-direct.h
> @@ -14,15 +14,21 @@ extern unsigned int zone_dma_bits;
> static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> {
> dma_addr_t dev_addr = (dma_addr_t)paddr;
> + /* The compiler should remove the 2nd term if !DMA_PFN_OFFSET_MAP */
> + unsigned long dma_pfn_offset = dev->dma_pfn_offset
> + + dma_pfn_offset_from_phys_addr(dev, paddr);
>
> - return dev_addr - ((dma_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
> + return dev_addr - ((dma_addr_t)dma_pfn_offset << PAGE_SHIFT);
> }
>
> static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dev_addr)
> {
> phys_addr_t paddr = (phys_addr_t)dev_addr;
> + /* The compiler should remove the 2nd term if !DMA_PFN_OFFSET_MAP */
> + unsigned long dma_pfn_offset = dev->dma_pfn_offset
> + + dma_pfn_offset_from_dma_addr(dev, paddr);
>
> - return paddr + ((phys_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
> + return paddr + ((phys_addr_t)dma_pfn_offset << PAGE_SHIFT);
> }
> #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */
>
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 330ad58fbf4d..91940bba2229 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -256,6 +256,52 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
> size_t dma_direct_max_mapping_size(struct device *dev);
>
> #ifdef CONFIG_HAS_DMA
> +#ifdef CONFIG_DMA_PFN_OFFSET_MAP
> +struct dma_pfn_offset_region {

> + phys_addr_t cpu_beg;
> + phys_addr_t cpu_end;
> + dma_addr_t dma_beg;
> + dma_addr_t dma_end;

Perhaps
s,beg,start,
in above names

> + unsigned long pfn_offset;
> +};
> +
> +static inline unsigned long dma_pfn_offset_from_dma_addr(struct device *dev,
> + dma_addr_t dma_addr)
> +{
> + const struct dma_pfn_offset_region *m = dev->dma_pfn_offset_map;

> + if (m)
> + for (; m->cpu_end; m++)

Why not simple

while (m) {
...
}

?

> + if (dma_addr >= m->dma_beg && dma_addr < m->dma_end)
> + return m->pfn_offset;
> + return 0;
> +}
> +
> +static inline unsigned long dma_pfn_offset_from_phys_addr(struct device *dev,
> + phys_addr_t paddr)
> +{
> + const struct dma_pfn_offset_region *m = dev->dma_pfn_offset_map;
> +

> + if (m)
> + for (; m->cpu_end; m++)

Ditto.

> + if (paddr >= m->cpu_beg && paddr < m->cpu_end)
> + return m->pfn_offset;
> + return 0;
> +}
> +#else /* CONFIG_DMA_PFN_OFFSET_MAP */
> +static inline unsigned long dma_pfn_offset_from_dma_addr(struct device *dev,
> + dma_addr_t dma_addr)
> +{
> + return 0;
> +}
> +
> +static inline unsigned long dma_pfn_offset_from_phys_addr(struct device *dev,
> + phys_addr_t paddr)
> +{
> + return 0;
> +}
> +#endif /* CONFIG_DMA_PFN_OFFSET_MAP */
> +
> #include <asm/dma-mapping.h>
>
> static inline const struct dma_map_ops *get_dma_ops(struct device *dev)
> diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
> index 4c103a24e380..ceb7e5e8f501 100644
> --- a/kernel/dma/Kconfig
> +++ b/kernel/dma/Kconfig
> @@ -195,3 +195,16 @@ config DMA_API_DEBUG_SG
> is technically out-of-spec.
>
> If unsure, say N.
> +
> +config DMA_PFN_OFFSET_MAP
> + bool "Uses a DMA range map to calculate PFN offset"
> + depends on PCIE_BRCMSTB

> + default n

Redundant.

> + help
> + Some devices have a dma-range that gets converted to
> + a dev->dma_pfn_offset value. This option is for the
> + atypical case of there being multiple dma-ranges requiring
> + multiple pfn offsets, which are selected from when
> + converting to phys to dma and vice versa.
> +
> + If unsure, say N.
> --
> 2.17.1
>

--
With Best Regards,
Andy Shevchenko

Next message: Nathan Chancellor: "[PATCH v2] powerpc/wii: Fix declaration made after definition"
Previous message: MickaÃl SalaÃn: "[PATCH v18 03/12] landlock: Set up the security framework and manage credentials"
In reply to: Jim Quinlan: "[PATCH v2 09/14] device core: Add ability to handle multiple dma offsets"
Next in thread: Jim Quinlan: "Re: [PATCH v2 09/14] device core: Add ability to handle multiple dma offsets"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]