USB: use genalloc for USB HCs with local memory

For HCs that have local memory, replace the current DMA API usage with
a genalloc generic allocator to manage the mappings for these devices.
To help users, introduce a new HCD API, usb_hcd_setup_local_mem() that
will setup up the genalloc backing up the device local memory. It will
be used in subsequent patches.  This is in preparation for dropping
the existing "coherent" dma mem declaration APIs.  The 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.

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Tested-by: Fredrik Noring <noring@nocrew.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

7 files changed, 102 insertions, 9 deletions

diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index e4b27413f528..389c57d8eba7 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -45,6 +45,7 @@ config USB_ARCH_HAS_HCD
 config USB
         tristate "Support for Host-side USB"
         depends on USB_ARCH_HAS_HCD
+        select GENERIC_ALLOCATOR
         select USB_COMMON
         select NLS  # for UTF-8 strings
         ---help---
diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c
index f641342cdec0..d2064ad7ad14 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>
 
@@ -124,6 +125,9 @@ void *hcd_buffer_alloc(
         if (size == 0)
                 return NULL;
 
+        if (hcd->localmem_pool)
+                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) &&
@@ -152,6 +156,11 @@ void hcd_buffer_free(
         if (!addr)
                 return;
 
+        if (hcd->localmem_pool) {
+                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))) {
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 94d22551fc1b..29b96e5e8621 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -29,6 +29,8 @@
 #include <linux/workqueue.h>
 #include <linux/pm_runtime.h>
 #include <linux/types.h>
+#include <linux/genalloc.h>
+#include <linux/io.h>
 
 #include <linux/phy/phy.h>
 #include <linux/usb.h>
@@ -3039,6 +3041,40 @@ usb_hcd_platform_shutdown(struct platform_device *dev)
 }
 EXPORT_SYMBOL_GPL(usb_hcd_platform_shutdown);
 
+int usb_hcd_setup_local_mem(struct usb_hcd *hcd, phys_addr_t phys_addr,
+                            dma_addr_t dma, size_t size)
+{
+        int err;
+        void *local_mem;
+
+        hcd->localmem_pool = devm_gen_pool_create(hcd->self.sysdev, PAGE_SHIFT,
+                                                  dev_to_node(hcd->self.sysdev),
+                                                  dev_name(hcd->self.sysdev));
+        if (IS_ERR(hcd->localmem_pool))
+                return PTR_ERR(hcd->localmem_pool);
+
+        local_mem = devm_memremap(hcd->self.sysdev, phys_addr,
+                                  size, MEMREMAP_WC);
+        if (!local_mem)
+                return -ENOMEM;
+
+        /*
+         * Here we pass a dma_addr_t but the arg type is a phys_addr_t.
+         * It's not backed by system memory and thus there's no kernel mapping
+         * for it.
+         */
+        err = gen_pool_add_virt(hcd->localmem_pool, (unsigned long)local_mem,
+                                dma, size, dev_to_node(hcd->self.sysdev));
+        if (err < 0) {
+                dev_err(hcd->self.sysdev, "gen_pool_add_virt failed with %d\n",
+                        err);
+                return err;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_setup_local_mem);
+
 /*-------------------------------------------------------------------------*/
 
 #if IS_ENABLED(CONFIG_USB_MON)
diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 210181fd98d2..b200b19b44fa 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->localmem_pool)
+                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->localmem_pool)
+                        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/drivers/usb/host/ohci-mem.c b/drivers/usb/host/ohci-mem.c
index 3965ac0341eb..4afe27cc7e46 100644
--- a/drivers/usb/host/ohci-mem.c
+++ b/drivers/usb/host/ohci-mem.c
@@ -36,6 +36,13 @@ static void ohci_hcd_init (struct ohci_hcd *ohci)
 
 static int ohci_mem_init (struct ohci_hcd *ohci)
 {
+        /*
+         * HCs with local memory allocate from localmem_pool so there's
+         * no need to create the below dma pools.
+         */
+        if (ohci_to_hcd(ohci)->localmem_pool)
+                return 0;
+
         ohci->td_cache = dma_pool_create ("ohci_td",
                 ohci_to_hcd(ohci)->self.controller,
                 sizeof (struct td),
@@ -84,8 +91,12 @@ td_alloc (struct ohci_hcd *hc, gfp_t mem_flags)
 {
         dma_addr_t      dma;
         struct td       *td;
+        struct usb_hcd  *hcd = ohci_to_hcd(hc);
 
-        td = dma_pool_zalloc (hc->td_cache, mem_flags, &dma);
+        if (hcd->localmem_pool)
+                td = gen_pool_dma_zalloc(hcd->localmem_pool, sizeof(*td), &dma);
+        else
+                td = dma_pool_zalloc(hc->td_cache, mem_flags, &dma);
         if (td) {
                 /* in case hc fetches it, make it look dead */
                 td->hwNextTD = cpu_to_hc32 (hc, dma);
@@ -99,6 +110,7 @@ static void
 td_free (struct ohci_hcd *hc, struct td *td)
 {
         struct td       **prev = &hc->td_hash [TD_HASH_FUNC (td->td_dma)];
+        struct usb_hcd  *hcd = ohci_to_hcd(hc);
 
         while (*prev && *prev != td)
                 prev = &(*prev)->td_hash;
@@ -106,7 +118,12 @@ td_free (struct ohci_hcd *hc, struct td *td)
                 *prev = td->td_hash;
         else if ((td->hwINFO & cpu_to_hc32(hc, TD_DONE)) != 0)
                 ohci_dbg (hc, "no hash for td %p\n", td);
-        dma_pool_free (hc->td_cache, td, td->td_dma);
+
+        if (hcd->localmem_pool)
+                gen_pool_free(hcd->localmem_pool, (unsigned long)td,
+                              sizeof(*td));
+        else
+                dma_pool_free(hc->td_cache, td, td->td_dma);
 }
 
 /*-------------------------------------------------------------------------*/
@@ -117,8 +134,12 @@ ed_alloc (struct ohci_hcd *hc, gfp_t mem_flags)
 {
         dma_addr_t      dma;
         struct ed       *ed;
+        struct usb_hcd  *hcd = ohci_to_hcd(hc);
 
-        ed = dma_pool_zalloc (hc->ed_cache, mem_flags, &dma);
+        if (hcd->localmem_pool)
+                ed = gen_pool_dma_zalloc(hcd->localmem_pool, sizeof(*ed), &dma);
+        else
+                ed = dma_pool_zalloc(hc->ed_cache, mem_flags, &dma);
         if (ed) {
                 INIT_LIST_HEAD (&ed->td_list);
                 ed->dma = dma;
@@ -129,6 +150,12 @@ ed_alloc (struct ohci_hcd *hc, gfp_t mem_flags)
 static void
 ed_free (struct ohci_hcd *hc, struct ed *ed)
 {
-        dma_pool_free (hc->ed_cache, ed, ed->dma);
+        struct usb_hcd  *hcd = ohci_to_hcd(hc);
+
+        if (hcd->localmem_pool)
+                gen_pool_free(hcd->localmem_pool, (unsigned long)ed,
+                              sizeof(*ed));
+        else
+                dma_pool_free(hc->ed_cache, ed, ed->dma);
 }
 
diff --git a/drivers/usb/host/ohci.h b/drivers/usb/host/ohci.h
index ef4813bfc5bf..b015b00774b2 100644
--- a/drivers/usb/host/ohci.h
+++ b/drivers/usb/host/ohci.h
@@ -385,6 +385,8 @@ struct ohci_hcd {
 
         /*
          * memory management for queue data structures
+         *
+         * @td_cache and @ed_cache are %NULL if &usb_hcd.localmem_pool is used.
          */
         struct dma_pool         *td_cache;
         struct dma_pool         *ed_cache;
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index bb57b5af4700..127560a4bfa0 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -216,6 +216,9 @@ struct usb_hcd {
 #define HC_IS_RUNNING(state) ((state) & __ACTIVE)
 #define HC_IS_SUSPENDED(state) ((state) & __SUSPEND)
 
+        /* memory pool for HCs having local memory, or %NULL */
+        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.
@@ -461,6 +464,8 @@ extern int usb_add_hcd(struct usb_hcd *hcd,
                 unsigned int irqnum, unsigned long irqflags);
 extern void usb_remove_hcd(struct usb_hcd *hcd);
 extern int usb_hcd_find_raw_port_number(struct usb_hcd *hcd, int port1);
+int usb_hcd_setup_local_mem(struct usb_hcd *hcd, phys_addr_t phys_addr,
+                            dma_addr_t dma, size_t size);
 
 struct platform_device;
 extern void usb_hcd_platform_shutdown(struct platform_device *dev);