Hi Magnus,
On 2016-09-20 20:54:33 +0900, Magnus Damm wrote:
> From: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
>
> Here's some prototype code that works around the lack of software
> support for mapping I/O devices to the SYS-DMAC hardware via the
> DMA Engine framework when using IOMMU.
>
> The code itself is one big layering violation that goes through
> the DT and unconditionally maps I/O devices using DMACs via the
> IPMMU device instance into iova space with a 1:1 mapping.
>
> This very short term prototype will for instance automatically make
> the SCIF serial port function with the IPMMU hardware in case the
> SYS-DMAC is hooked up to the IPMMU device.
>
> Not to be confused with the more long term solution to allow the
> DMA Engine framework to map I/O device memory dynamically.
Good news, Vinod queued the dma_{map,unmap}_resource API and rcar-dmac
usage of it yesterday \o/.
>
> Not-Yet-Signed-off-by: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
> ---
>
> Applies on top of: renesas-drivers-2016-09-13-v4.8-rc6
>
> drivers/iommu/ipmmu-vmsa.c | 75 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 75 insertions(+)
>
> --- 0001/drivers/iommu/ipmmu-vmsa.c
> +++ work/drivers/iommu/ipmmu-vmsa.c 2016-09-20 20:03:37.620607110 +0900
> @@ -19,6 +19,7 @@
> #include <linux/iommu.h>
> #include <linux/module.h>
> #include <linux/of.h>
> +#include <linux/of_address.h>
> #include <linux/of_iommu.h>
> #include <linux/platform_device.h>
> #include <linux/sizes.h>
> @@ -625,6 +626,78 @@ static void ipmmu_domain_free(struct iom
> kfree(domain);
> }
>
> +static void ipmmu_workaround_map(struct iommu_domain *io_domain,
> + struct device *dma_dev, struct resource *res)
> +{
> + phys_addr_t phys_addr;
> +
> + dev_info(dma_dev, "map %pr\n", res);
> +
> + phys_addr = iommu_iova_to_phys(io_domain, res->start);
> + if (phys_addr)
> + return;
> +
> + iommu_map(io_domain, res->start, res->start,
> + ALIGN(resource_size(res), SZ_4K),
> + IOMMU_READ | IOMMU_WRITE);
> +}
> +
> +static void ipmmu_workaround_dt(struct iommu_domain *io_domain,
> + struct device *dev,
> + void (*match)(struct iommu_domain *io_domain,
> + struct device *dma_dev,
> + struct resource *res))
> +{
> + struct device_node *np = NULL;
> + struct of_phandle_args dma_spec;
> + struct resource r;
> + int i, cnt;
> + bool found;
> +
> + /* Locate I/O devices using the DMAC and map their registers */
> + while ((np = of_find_all_nodes(np))) {
> + if (!of_find_property(np, "dmas", NULL))
> + continue;
> +
> + cnt = of_property_count_strings(np, "dma-names");
> + if (cnt < 0)
> + continue;
> +
> + found = false;
> + for (i = 0; i < cnt; i++) {
> + if (of_parse_phandle_with_args(np, "dmas",
> + "#dma-cells", i,
> + &dma_spec))
> + continue;
> +
> + if (dma_spec.np == dev->of_node)
> + found = true;
> +
> + of_node_put(dma_spec.np);
> + }
> +
> + if (!found)
> + continue;
> +
> + i = 0;
> + while (!of_address_to_resource(np, i, &r)) {
> + match(io_domain, dev, &r);
> + i++;
> + }
> + }
> +}
> +
> +static void ipmmu_workaround(struct iommu_domain *io_domain,
> + struct device *dev)
> +{
> + /* only apply workaround for DMA controllers */
> + if (!strstr(dev_name(dev), "dma-controller"))
> + return;
> +
> + dev_info(dev, "Adding iommu workaround to map I/O devices for DMACs\n");
> + ipmmu_workaround_dt(io_domain, dev, ipmmu_workaround_map);
> +}
> +
> static int ipmmu_attach_device(struct iommu_domain *io_domain,
> struct device *dev)
> {
> @@ -678,6 +751,8 @@ static int ipmmu_attach_device(struct io
> if (ret < 0)
> return ret;
>
> + ipmmu_workaround(io_domain, dev);
> +
> for (i = 0; i < archdata->num_utlbs; ++i)
> ipmmu_utlb_enable(domain, archdata->utlbs[i]);
>
--
Regards,
Niklas Söderlund
