[PATCH v3 0/3] prerequisites for device reserved local mem rework

[PATCH v3 0/3] prerequisites for device reserved local mem rework

[laurentiu.tudor]

From: Laurentiu Tudor <laurentiu.tudor@nxp.com>

For HCs that have local memory, replace the current DMA API usage
with a genalloc generic allocator to manage the mappings for these
devices.
This is in preparation for dropping the existing "coherent" dma
mem declaration APIs. Current implementation was relying on a short
circuit in the DMA API that in the end, was acting as an allocator
for these type of devices.

Only compiled tested, so any volunteers willing to test are most welcome.

Thank you!

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

Changes in v3:
 - rearranged calls into genalloc simplifying the code a bit (Christoph)
 - dropped RFC prefix

Changes in v2:
 - use genalloc also in core usb (based on comment from Robin)
 - moved genpool decl to usb_hcd to be accesible from core usb

Laurentiu Tudor (3):
  USB: use genalloc for USB HCs with local memory
  usb: host: ohci-sm501: init genalloc for local memory
  usb: host: ohci-tmio: init genalloc for local memory

 drivers/usb/core/buffer.c     | 16 +++++++---
 drivers/usb/host/ohci-hcd.c   | 23 +++++++++++---
 drivers/usb/host/ohci-sm501.c | 60 +++++++++++++++++++----------------
 drivers/usb/host/ohci-tmio.c  | 23 +++++++++-----
 include/linux/usb/hcd.h       |  3 ++
 5 files changed, 81 insertions(+), 44 deletions(-)

-- 
2.17.1

[PATCH v3 1/3] USB: use genalloc for USB HCs with local memory

[laurentiu.tudor]

From: Laurentiu Tudor <laurentiu.tudor@nxp.com>

For HCs that have local memory, replace the current DMA API usage
with a genalloc generic allocator to manage the mappings for these
devices.
This is in preparation for dropping the existing "coherent" dma
mem declaration APIs. Current implementation was relying on a short
circuit in the DMA API that in the end, was acting as an allocator
for these type of devices.

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

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
---
 drivers/usb/core/buffer.c   | 16 ++++++++++++----
 drivers/usb/host/ohci-hcd.c | 23 ++++++++++++++++++-----
 include/linux/usb/hcd.h     |  3 +++
 3 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c
index f641342cdec0..09669208b032 100644
--- a/drivers/usb/core/buffer.c
+++ b/drivers/usb/core/buffer.c
@@ -16,6 +16,7 @@
 #include <linux/io.h>
 #include <linux/dma-mapping.h>
 #include <linux/dmapool.h>
+#include <linux/genalloc.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
 
@@ -124,10 +125,12 @@ void *hcd_buffer_alloc(
 	if (size == 0)
 		return NULL;
 
+	if (hcd->driver->flags & HCD_LOCAL_MEM)
+		return gen_pool_dma_alloc(hcd->localmem_pool, size, dma);
+
 	/* some USB hosts just use PIO */
 	if (!IS_ENABLED(CONFIG_HAS_DMA) ||
-	    (!is_device_dma_capable(bus->sysdev) &&
-	     !(hcd->driver->flags & HCD_LOCAL_MEM))) {
+	    !is_device_dma_capable(bus->sysdev)) {
 		*dma = ~(dma_addr_t) 0;
 		return kmalloc(size, mem_flags);
 	}
@@ -152,9 +155,14 @@ void hcd_buffer_free(
 	if (!addr)
 		return;
 
+	if (hcd->driver->flags & HCD_LOCAL_MEM) {
+		gen_pool_free(hcd->localmem_pool, (unsigned long)addr,
+			      size);
+		return;
+	}
+
 	if (!IS_ENABLED(CONFIG_HAS_DMA) ||
-	    (!is_device_dma_capable(bus->sysdev) &&
-	     !(hcd->driver->flags & HCD_LOCAL_MEM))) {
+	    !is_device_dma_capable(bus->sysdev)) {
 		kfree(addr);
 		return;
 	}
diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 210181fd98d2..f9462c372943 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -40,6 +40,7 @@
 #include <linux/dmapool.h>
 #include <linux/workqueue.h>
 #include <linux/debugfs.h>
+#include <linux/genalloc.h>
 
 #include <asm/io.h>
 #include <asm/irq.h>
@@ -505,8 +506,15 @@ static int ohci_init (struct ohci_hcd *ohci)
 	timer_setup(&ohci->io_watchdog, io_watchdog_func, 0);
 	ohci->prev_frame_no = IO_WATCHDOG_OFF;
 
-	ohci->hcca = dma_alloc_coherent (hcd->self.controller,
-			sizeof(*ohci->hcca), &ohci->hcca_dma, GFP_KERNEL);
+	if (hcd->driver->flags & HCD_LOCAL_MEM)
+		ohci->hcca = gen_pool_dma_alloc(hcd->localmem_pool,
+						sizeof(*ohci->hcca),
+						&ohci->hcca_dma);
+	else
+		ohci->hcca = dma_alloc_coherent(hcd->self.controller,
+						sizeof(*ohci->hcca),
+						&ohci->hcca_dma,
+						GFP_KERNEL);
 	if (!ohci->hcca)
 		return -ENOMEM;
 
@@ -990,9 +998,14 @@ static void ohci_stop (struct usb_hcd *hcd)
 	remove_debug_files (ohci);
 	ohci_mem_cleanup (ohci);
 	if (ohci->hcca) {
-		dma_free_coherent (hcd->self.controller,
-				sizeof *ohci->hcca,
-				ohci->hcca, ohci->hcca_dma);
+		if (hcd->driver->flags & HCD_LOCAL_MEM)
+			gen_pool_free(hcd->localmem_pool,
+				      (unsigned long)ohci->hcca,
+				      sizeof(*ohci->hcca));
+		else
+			dma_free_coherent(hcd->self.controller,
+					  sizeof(*ohci->hcca),
+					  ohci->hcca, ohci->hcca_dma);
 		ohci->hcca = NULL;
 		ohci->hcca_dma = 0;
 	}
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 695931b03684..0fee81ef5d52 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -215,6 +215,9 @@ struct usb_hcd {
 #define	HC_IS_RUNNING(state) ((state) & __ACTIVE)
 #define	HC_IS_SUSPENDED(state) ((state) & __SUSPEND)
 
+	/* allocator for HCs having local memory */
+	struct gen_pool         *localmem_pool;
+
 	/* more shared queuing code would be good; it should support
 	 * smarter scheduling, handle transaction translators, etc;
 	 * input size of periodic table to an interrupt scheduler.
-- 
2.17.1

[PATCH v3 2/3] usb: host: ohci-sm501: init genalloc for local memory

[laurentiu.tudor]

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

[PATCH v3 3/3] usb: host: ohci-tmio: init genalloc for local memory

[laurentiu.tudor]

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-tmio.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/host/ohci-tmio.c b/drivers/usb/host/ohci-tmio.c
index f88a0370659f..34869382618f 100644
--- a/drivers/usb/host/ohci-tmio.c
+++ b/drivers/usb/host/ohci-tmio.c
@@ -30,6 +30,7 @@
 #include <linux/mfd/core.h>
 #include <linux/mfd/tmio.h>
 #include <linux/dma-mapping.h>
+#include <linux/genalloc.h>
 
 /*-------------------------------------------------------------------------*/
 
@@ -224,11 +225,6 @@ static int ohci_hcd_tmio_drv_probe(struct platform_device *dev)
 		goto err_ioremap_regs;
 	}
 
-	ret = dma_declare_coherent_memory(&dev->dev, sram->start, sram->start,
-				resource_size(sram));
-	if (ret)
-		goto err_dma_declare;
-
 	if (cell->enable) {
 		ret = cell->enable(dev);
 		if (ret)
@@ -239,6 +235,20 @@ static int ohci_hcd_tmio_drv_probe(struct platform_device *dev)
 	ohci = hcd_to_ohci(hcd);
 	ohci_hcd_init(ohci);
 
+	hcd->localmem_pool = devm_gen_pool_create(&dev->dev, PAGE_SHIFT,
+						  dev_to_node(&dev->dev),
+						  "ohci-sm501");
+	if (IS_ERR(hcd->localmem_pool)) {
+		ret = PTR_ERR(hcd->localmem_pool);
+		goto err_enable;
+	}
+	ret = gen_pool_add_virt(hcd->localmem_pool, sram->start, sram->start,
+				resource_size(sram), dev_to_node(&dev->dev));
+	if (ret < 0) {
+		dev_err(&dev->dev, "failed to add to pool: %d\n", ret);
+		goto err_enable;
+	}
+
 	ret = usb_add_hcd(hcd, irq, 0);
 	if (ret)
 		goto err_add_hcd;
@@ -254,8 +264,6 @@ static int ohci_hcd_tmio_drv_probe(struct platform_device *dev)
 	if (cell->disable)
 		cell->disable(dev);
 err_enable:
-	dma_release_declared_memory(&dev->dev);
-err_dma_declare:
 	iounmap(hcd->regs);
 err_ioremap_regs:
 	iounmap(tmio->ccr);
@@ -276,7 +284,6 @@ static int ohci_hcd_tmio_drv_remove(struct platform_device *dev)
 	tmio_stop_hc(dev);
 	if (cell->disable)
 		cell->disable(dev);
-	dma_release_declared_memory(&dev->dev);
 	iounmap(hcd->regs);
 	iounmap(tmio->ccr);
 	usb_put_hcd(hcd);
-- 
2.17.1