On Fri, Aug 09, 2019 at 07:34:48PM +0200, marek.vasut@xxxxxxxxx wrote:
> From: Oza Pawandeep <oza.oza@xxxxxxxxxxxx>
>
> The patch exports interface to PCIe RC drivers so that,
> Drivers can get their inbound memory configuration.
>
> It provides basis for IOVA reservations for inbound memory
> holes, if RC is not capable of addressing all the host memory,
> Specifically when IOMMU is enabled and on ARMv8 where 64bit IOVA
> could be allocated.
>
> It handles multiple inbound windows, and returns resources,
> and is left to the caller, how it wants to use them.
>
> Signed-off-by: Oza Pawandeep <oza.oza@xxxxxxxxxxxx>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Cc: Robin Murphy <robin.murphy@xxxxxxx>
> Cc: Simon Horman <horms+renesas@xxxxxxxxxxxx>
> Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx>
> Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
> To: linux-pci@xxxxxxxxxxxxxxx
> ---
> drivers/pci/of.c | 96 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/of_pci.h | 7 +++
> 2 files changed, 103 insertions(+)
>
> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> index bc7b27a28795..4018f1a26f6f 100644
> --- a/drivers/pci/of.c
> +++ b/drivers/pci/of.c
> @@ -347,6 +347,102 @@ int devm_of_pci_get_host_bridge_resources(struct device *dev,
> return err;
> }
> EXPORT_SYMBOL_GPL(devm_of_pci_get_host_bridge_resources);
> +
> +/**
> + * of_pci_get_dma_ranges - Parse PCI host bridge inbound resources from DT
> + * @np: device node of the host bridge having the dma-ranges property
> + * @resources: list where the range of resources will be added after DT parsing
> + *
> + * It is the caller's job to free the @resources list.
> + *
> + * This function will parse the "dma-ranges" property of a
> + * PCI host bridge device node and setup the resource mapping based
> + * on its content.
> + *
> + * It returns zero if the range parsing has been successful or a standard error
> + * value if it failed.
> + */
> +
> +int of_pci_get_dma_ranges(struct device_node *dn, struct list_head *resources)
> +{
> + struct device_node *node = of_node_get(dn);
> + int rlen;
> + int pna = of_n_addr_cells(node);
> + const int na = 3, ns = 2;
> + int np = pna + na + ns;
> + int ret = 0;
> + struct resource *res;
> + const u32 *dma_ranges;
It seems that const __be32 * would be a more appropriate type
for dma_ranges as that seems to be the expected type in
all uses below.
> + struct of_pci_range range;
> +
> + if (!node)
> + return -EINVAL;
> +
> + while (1) {
> + dma_ranges = of_get_property(node, "dma-ranges", &rlen);
> +
> + /* Ignore empty ranges, they imply no translation required. */
> + if (dma_ranges && rlen > 0)
> + break;
> +
> + /* no dma-ranges, they imply no translation required. */
> + if (!dma_ranges)
> + break;
> +
> + node = of_get_next_parent(node);
> +
> + if (!node)
> + break;
> + }
> +
> + if (!dma_ranges) {
> + pr_debug("pcie device has no dma-ranges defined for node(%s)\n",
> + dn->full_name);
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + while ((rlen -= np * 4) >= 0) {
> + range.pci_space = be32_to_cpup((const __be32 *) &dma_ranges[0]);
Can &dma_ranges[0] be more succinctly written as dma_ranges ?
> + range.pci_addr = of_read_number(dma_ranges + 1, ns);
> + range.cpu_addr = of_translate_dma_address(node,
> + dma_ranges + na);
> + range.size = of_read_number(dma_ranges + pna + na, ns);
> + range.flags = IORESOURCE_MEM;
> +
> + dma_ranges += np;
> +
> + /*
> + * If we failed translation or got a zero-sized region
> + * then skip this range.
> + */
> + if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
> + continue;
> +
> + res = kzalloc(sizeof(struct resource), GFP_KERNEL);
> + if (!res) {
> + ret = -ENOMEM;
> + goto parse_failed;
> + }
> +
> + ret = of_pci_range_to_resource(&range, dn, res);
> + if (ret) {
> + kfree(res);
> + continue;
> + }
> +
> + pci_add_resource_offset(resources, res,
> + res->start - range.pci_addr);
> + }
> + return ret;
> +
> +parse_failed:
> + pci_free_resource_list(resources);
> +out:
> + of_node_put(node);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(of_pci_get_dma_ranges);
> #endif /* CONFIG_OF_ADDRESS */
>
> #if IS_ENABLED(CONFIG_OF_IRQ)
> diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
> index 21a89c4880fa..02bff0587dd2 100644
> --- a/include/linux/of_pci.h
> +++ b/include/linux/of_pci.h
> @@ -13,6 +13,7 @@ struct device_node;
> struct device_node *of_pci_find_child_device(struct device_node *parent,
> unsigned int devfn);
> int of_pci_get_devfn(struct device_node *np);
> +int of_pci_get_dma_ranges(struct device_node *np, struct list_head *resources);
> void of_pci_check_probe_only(void);
> #else
> static inline struct device_node *of_pci_find_child_device(struct device_node *parent,
> @@ -26,6 +27,12 @@ static inline int of_pci_get_devfn(struct device_node *np)
> return -EINVAL;
> }
>
> +static inline int of_pci_get_dma_ranges(struct device_node *np,
> + struct list_head *resources)
> +{
> + return -EINVAL;
> +}
> +
> static inline void of_pci_check_probe_only(void) { }
> #endif
>
> --
> 2.20.1
>
