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Subject[PATCH v3 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 | 60 +++++++++++++++++++----------------
1 file changed, 33 insertions(+), 27 deletions(-)

diff --git a/drivers/usb/host/ohci-sm501.c b/drivers/usb/host/ohci-sm501.c
index c26228c25f99..8b829eca04ab 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>

@@ -110,40 +111,18 @@ 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 +143,36 @@ 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;
+ }
+ retval = gen_pool_add_virt(hcd->localmem_pool,
+ (unsigned long)mem->start -
+ mem->parent->start,
+ mem->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 +190,6 @@ 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 +204,6 @@ 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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