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    Subject[PATCH v4 2/3] usb: host: ohci-sm501: init genalloc for local memory
    Date
    From: Laurentiu Tudor <laurentiu.tudor@nxp.com>

    In preparation for dropping the existing "coherent" dma mem declaration
    APIs, replace the current dma_declare_coherent_memory() based mechanism
    with the creation of a genalloc pool that will be used in the OHCI
    subsystem as replacement for the DMA APIs.

    For context, see thread here: https://lkml.org/lkml/2019/4/22/357

    Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
    ---
    drivers/usb/host/ohci-sm501.c | 68 +++++++++++++++++++++--------------
    1 file changed, 41 insertions(+), 27 deletions(-)

    diff --git a/drivers/usb/host/ohci-sm501.c b/drivers/usb/host/ohci-sm501.c
    index c26228c25f99..1a25f5396e3e 100644
    --- a/drivers/usb/host/ohci-sm501.c
    +++ b/drivers/usb/host/ohci-sm501.c
    @@ -16,6 +16,7 @@
    #include <linux/jiffies.h>
    #include <linux/platform_device.h>
    #include <linux/dma-mapping.h>
    +#include <linux/genalloc.h>
    #include <linux/sm501.h>
    #include <linux/sm501-regs.h>

    @@ -92,6 +93,7 @@ static int ohci_hcd_sm501_drv_probe(struct platform_device *pdev)
    struct resource *res, *mem;
    int retval, irq;
    struct usb_hcd *hcd = NULL;
    + void __iomem *local_mem;

    irq = retval = platform_get_irq(pdev, 0);
    if (retval < 0)
    @@ -110,40 +112,18 @@ static int ohci_hcd_sm501_drv_probe(struct platform_device *pdev)
    goto err0;
    }

    - /* The sm501 chip is equipped with local memory that may be used
    - * by on-chip devices such as the video controller and the usb host.
    - * This driver uses dma_declare_coherent_memory() to make sure
    - * usb allocations with dma_alloc_coherent() allocate from
    - * this local memory. The dma_handle returned by dma_alloc_coherent()
    - * will be an offset starting from 0 for the first local memory byte.
    - *
    - * So as long as data is allocated using dma_alloc_coherent() all is
    - * fine. This is however not always the case - buffers may be allocated
    - * using kmalloc() - so the usb core needs to be told that it must copy
    - * data into our local memory if the buffers happen to be placed in
    - * regular memory. The HCD_LOCAL_MEM flag does just that.
    - */
    -
    - retval = dma_declare_coherent_memory(dev, mem->start,
    - mem->start - mem->parent->start,
    - resource_size(mem));
    - if (retval) {
    - dev_err(dev, "cannot declare coherent memory\n");
    - goto err1;
    - }
    -
    /* allocate, reserve and remap resources for registers */
    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (res == NULL) {
    dev_err(dev, "no resource definition for registers\n");
    retval = -ENOENT;
    - goto err2;
    + goto err1;
    }

    hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev));
    if (!hcd) {
    retval = -ENOMEM;
    - goto err2;
    + goto err1;
    }

    hcd->rsrc_start = res->start;
    @@ -164,6 +144,43 @@ static int ohci_hcd_sm501_drv_probe(struct platform_device *pdev)

    ohci_hcd_init(hcd_to_ohci(hcd));

    + /* The sm501 chip is equipped with local memory that may be used
    + * by on-chip devices such as the video controller and the usb host.
    + * This driver uses genalloc so that usb allocations with
    + * gen_pool_dma_alloc() allocate from this local memory. The dma_handle
    + * returned by gen_pool_dma_alloc() will be an offset starting from 0
    + * for the first local memory byte.
    + *
    + * So as long as data is allocated using gen_pool_dma_alloc() all is
    + * fine. This is however not always the case - buffers may be allocated
    + * using kmalloc() - so the usb core needs to be told that it must copy
    + * data into our local memory if the buffers happen to be placed in
    + * regular memory. The HCD_LOCAL_MEM flag does just that.
    + */
    +
    + hcd->localmem_pool = devm_gen_pool_create(dev, PAGE_SHIFT,
    + dev_to_node(dev),
    + "ohci-sm501");
    + if (IS_ERR(hcd->localmem_pool)) {
    + retval = PTR_ERR(hcd->localmem_pool);
    + goto err5;
    + }
    +
    + local_mem = devm_ioremap(dev, mem->start, resource_size(mem));
    + if (!local_mem) {
    + retval = -ENOMEM;
    + goto err5;
    + }
    +
    + retval = gen_pool_add_virt(hcd->localmem_pool,
    + (unsigned long)local_mem,
    + mem->start - mem->parent->start,
    + resource_size(mem),
    + dev_to_node(dev));
    + if (retval < 0) {
    + dev_err(dev, "failed to add to pool: %d\n", retval);
    + goto err5;
    + }
    retval = usb_add_hcd(hcd, irq, IRQF_SHARED);
    if (retval)
    goto err5;
    @@ -181,8 +198,6 @@ static int ohci_hcd_sm501_drv_probe(struct platform_device *pdev)
    release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
    err3:
    usb_put_hcd(hcd);
    -err2:
    - dma_release_declared_memory(dev);
    err1:
    release_mem_region(mem->start, resource_size(mem));
    err0:
    @@ -197,7 +212,6 @@ static int ohci_hcd_sm501_drv_remove(struct platform_device *pdev)
    usb_remove_hcd(hcd);
    release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
    usb_put_hcd(hcd);
    - dma_release_declared_memory(&pdev->dev);
    mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
    if (mem)
    release_mem_region(mem->start, resource_size(mem));
    --
    2.17.1
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