diff mbox series

[v4,2/3] usb: host: ohci-sm501: init genalloc for local memory

Message ID 20190516114721.27694-3-laurentiu.tudor@nxp.com (mailing list archive)
State Superseded
Headers show
Series prerequisites for device reserved local mem rework | expand

Commit Message

Laurentiu Tudor May 16, 2019, 11:47 a.m. UTC 
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(-)

Comments

Christoph Hellwig May 21, 2019, 10:39 a.m. UTC | #1 
On Thu, May 16, 2019 at 02:47:20PM +0300, laurentiu.tudor@nxp.com wrote:
> +	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));

I wonder if having a helper for these operations would be useful,
explaining what we do here.  That is create a pool for a resource,
where the virtual address is the ioremap of said resource.  We
could also make that a managed API so that you can get rid of the
cleanup path.
Laurentiu Tudor May 21, 2019, 11:08 a.m. UTC | #2 
On 21.05.2019 13:39, Christoph Hellwig wrote:
> On Thu, May 16, 2019 at 02:47:20PM +0300, laurentiu.tudor@nxp.com wrote:
>> +	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));
> 
> I wonder if having a helper for these operations would be useful,
> explaining what we do here.  That is create a pool for a resource,
> where the virtual address is the ioremap of said resource.  We
> could also make that a managed API so that you can get rid of the
> cleanup path.

This is close to what I've already prepared in the next spin. It's a new 
usb hcd api so it's not as abstract as your idea. I think we can discuss 
on it after I'll send it.

---
Best Regards, Laurentiu
diff mbox series

Patch

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));