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    SubjectRe: [RFC PATCH v2 0/3] prerequisites for device reserved local mem rework
    Hi Lauretniu,

    > I think that any recent kernel will do, so I'd say your current branch
    > should be fine.

    The kernel oopses with "unable to handle kernel paging request at virtual
    address 000aba0b" in hcd_alloc_coherent via usb_hcd_map_urb_for_dma. This
    relates to patch 2/3 that I didn't quite understand, where

    - retval = dma_declare_coherent_memory(dev, mem->start,
    - mem->start - mem->parent->start,
    - resource_size(mem));

    becomes

    + retval = gen_pool_add_virt(hcd->localmem_pool,
    + (unsigned long)mem->start -
    + mem->parent->start,
    + mem->start, resource_size(mem),

    so that arguments two and three switch places. Given

    int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
    dma_addr_t device_addr, size_t size);

    and

    int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phys
    size_t size, int nid)

    it seems that the device address (dma_addr_t device_addr) now becomes a
    virtual address (unsigned long virt). Is that intended?

    My corresponding patch is below for reference. I applied your 1/3 patch
    to test it.

    Fredrik

    diff --git a/drivers/usb/host/ohci-ps2.c b/drivers/usb/host/ohci-ps2.c
    --- a/drivers/usb/host/ohci-ps2.c
    +++ b/drivers/usb/host/ohci-ps2.c
    @@ -7,6 +7,7 @@
    */

    #include <linux/dma-mapping.h>
    +#include <linux/genalloc.h>
    #include <linux/module.h>
    #include <linux/platform_device.h>
    #include <linux/usb.h>
    @@ -92,12 +93,12 @@ static irqreturn_t ohci_ps2_irq(struct usb_hcd *hcd)
    return ohci_irq(hcd); /* Call normal IRQ handler. */
    }

    -static int iopheap_alloc_coherent(struct platform_device *pdev,
    - size_t size, int flags)
    +static int iopheap_alloc_coherent(struct platform_device *pdev, size_t size)
    {
    struct device *dev = &pdev->dev;
    struct usb_hcd *hcd = platform_get_drvdata(pdev);
    struct ps2_hcd *ps2priv = hcd_to_priv(hcd);
    + int err;

    if (ps2priv->iop_dma_addr != 0)
    return 0;
    @@ -112,28 +113,37 @@ static int iopheap_alloc_coherent(struct platform_device *pdev,
    return -ENOMEM;
    }

    - if (dma_declare_coherent_memory(dev,
    - iop_bus_to_phys(ps2priv->iop_dma_addr),
    - ps2priv->iop_dma_addr, size, flags)) {
    - dev_err(dev, "dma_declare_coherent_memory failed\n");
    - iop_free(ps2priv->iop_dma_addr);
    - ps2priv->iop_dma_addr = 0;
    - return -ENOMEM;
    + hcd->localmem_pool = devm_gen_pool_create(dev,
    + PAGE_SHIFT, dev_to_node(dev), DRV_NAME);
    + if (IS_ERR(hcd->localmem_pool)) {
    + err = PTR_ERR(hcd->localmem_pool);
    + goto out_err;
    + }
    +
    + err = gen_pool_add_virt(hcd->localmem_pool, ps2priv->iop_dma_addr,
    + iop_bus_to_phys(ps2priv->iop_dma_addr), size, dev_to_node(dev));
    + if (err < 0) {
    + dev_err(dev, "gen_pool_add_virt failed with %d\n", err);
    + goto out_err;
    }

    return 0;
    +
    +out_err:
    + iop_free(ps2priv->iop_dma_addr);
    + ps2priv->iop_dma_addr = 0;
    +
    + return err;
    }

    static void iopheap_free_coherent(struct platform_device *pdev)
    {
    - struct device *dev = &pdev->dev;
    struct usb_hcd *hcd = platform_get_drvdata(pdev);
    struct ps2_hcd *ps2priv = hcd_to_priv(hcd);

    if (ps2priv->iop_dma_addr == 0)
    return;

    - dma_release_declared_memory(dev);
    iop_free(ps2priv->iop_dma_addr);
    ps2priv->iop_dma_addr = 0;
    }
    @@ -177,8 +187,7 @@ static int ohci_hcd_ps2_probe(struct platform_device *pdev)
    goto err;
    }

    - ret = iopheap_alloc_coherent(pdev,
    - DMA_BUFFER_SIZE, DMA_MEMORY_EXCLUSIVE);
    + ret = iopheap_alloc_coherent(pdev, DMA_BUFFER_SIZE);
    if (ret != 0)
    goto err_alloc_coherent;

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