/* * DMA memory management for framework level HCD code (hc_driver) * * This implementation plugs in through generic "usb_bus" level methods, * and should work with all USB controllers, regardless of bus type. * * Released under the GPLv2 only. * SPDX-License-Identifier: GPL-2.0 */ #include <linux/module.h>#include <linux/kernel.h>#include <linux/slab.h>#include <linux/device.h>#include <linux/mm.h>#include <linux/io.h>#include <linux/dma-mapping.h>#include <linux/dmapool.h>#include <linux/usb.h>#include <linux/usb/hcd.h>  /* * DMA-Coherent Buffers */ /* FIXME tune these based on pool statistics ... */static size_t pool_max[HCD_BUFFER_POOLS] = {	32, 128, 512, 2048,}; void __init usb_init_pool_max(void){	/*	 * The pool_max values must never be smaller than	 * ARCH_KMALLOC_MINALIGN.	 */	if (ARCH_KMALLOC_MINALIGN <= 32)		;			/* Original value is okay */	else if (ARCH_KMALLOC_MINALIGN <= 64)		pool_max[0] = 64;	else if (ARCH_KMALLOC_MINALIGN <= 128)		pool_max[0] = 0;	/* Don't use this pool */	else		BUILD_BUG();		/* We don't allow this */} /* SETUP primitives */ /** * hcd_buffer_create - initialize buffer pools * @hcd: the bus whose buffer pools are to be initialized * Context: !in_interrupt() * * Call this as part of initializing a host controller that uses the dma * memory allocators.  It initializes some pools of dma-coherent memory that * will be shared by all drivers using that controller. * * Call hcd_buffer_destroy() to clean up after using those pools. * * Return: 0 if successful. A negative errno value otherwise. */int hcd_buffer_create(struct usb_hcd *hcd){	char		name[16];	int		i, size; 	if (!IS_ENABLED(CONFIG_HAS_DMA) ||	    (!hcd->self.controller->dma_mask &&	     !(hcd->driver->flags & HCD_LOCAL_MEM)))		return 0; 	for (i = 0; i < HCD_BUFFER_POOLS; i++) {		size = pool_max[i];		if (!size)			continue;		snprintf(name, sizeof(name), "buffer-%d", size);		hcd->pool[i] = dma_pool_create(name, hcd->self.controller,				size, size, 0);		if (!hcd->pool[i]) {			hcd_buffer_destroy(hcd);			return -ENOMEM;		}	}	return 0;}  /** * hcd_buffer_destroy - deallocate buffer pools * @hcd: the bus whose buffer pools are to be destroyed * Context: !in_interrupt() * * This frees the buffer pools created by hcd_buffer_create(). */void hcd_buffer_destroy(struct usb_hcd *hcd){	int i; 	if (!IS_ENABLED(CONFIG_HAS_DMA))		return; 	for (i = 0; i < HCD_BUFFER_POOLS; i++) {		struct dma_pool *pool = hcd->pool[i]; 		if (pool) {			dma_pool_destroy(pool);			hcd->pool[i] = NULL;		}	}}  /* sometimes alloc/free could use kmalloc with GFP_DMA, for * better sharing and to leverage mm/slab.c intelligence. */ void *hcd_buffer_alloc(	struct usb_bus		*bus,	size_t			size,	gfp_t			mem_flags,	dma_addr_t		*dma){	struct usb_hcd		*hcd = bus_to_hcd(bus);	int			i; 	if (size == 0)		return NULL; 	/* some USB hosts just use PIO */	if (!IS_ENABLED(CONFIG_HAS_DMA) ||	    (!bus->controller->dma_mask &&	     !(hcd->driver->flags & HCD_LOCAL_MEM))) {		*dma = ~(dma_addr_t) 0;		return kmalloc(size, mem_flags);	} 	for (i = 0; i < HCD_BUFFER_POOLS; i++) {		if (size <= pool_max[i])			return dma_pool_alloc(hcd->pool[i], mem_flags, dma);	}	return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags);} void hcd_buffer_free(	struct usb_bus		*bus,	size_t			size,	void			*addr,	dma_addr_t		dma){	struct usb_hcd		*hcd = bus_to_hcd(bus);	int			i; 	if (!addr)		return; 	if (!IS_ENABLED(CONFIG_HAS_DMA) ||	    (!bus->controller->dma_mask &&	     !(hcd->driver->flags & HCD_LOCAL_MEM))) {		kfree(addr);		return;	} 	for (i = 0; i < HCD_BUFFER_POOLS; i++) {		if (size <= pool_max[i]) {			dma_pool_free(hcd->pool[i], addr, dma);			return;		}	}	dma_free_coherent(hcd->self.controller, size, addr, dma);}