libsel4platsupport/src/io.c - 3p/sel4/sel4_libs - Git at Google

 /*
  * Copyright 2017, Data61
  * Commonwealth Scientific and Industrial Research Organisation (CSIRO)
  * ABN 41 687 119 230.
  *
  * This software may be distributed and modified according to the terms of
  * the BSD 2-Clause license. Note that NO WARRANTY is provided.
  * See "LICENSE_BSD2.txt" for details.
  *
  * @TAG(DATA61_BSD)
  */

 #include <autoconf.h>
 #include <sel4platsupport/gen_config.h>

 #include <sel4platsupport/io.h>
 #ifdef CONFIG_ARCH_ARM
 #include <platsupport/clock.h>
 #include <platsupport/mux.h>
 #endif
 #include <utils/util.h>
 #include <vspace/page.h>

 #include <vspace/vspace.h>
 #include <vka/capops.h>

 #include <stdint.h>
 #include <stdlib.h>

 typedef struct io_mapping {
     /* address we returned to the user */
     void *returned_addr;
     /* base address of the mapping with respect to the vspace */
     void *mapped_addr;
     size_t num_pages;
     size_t page_size;
     size_t page_size_bits;
     /* caps for the mappings (s) */
     seL4_CPtr *caps;
     /* allocation cookie for allocation(s) */
     seL4_Word *alloc_cookies;
     struct io_mapping *next, *prev;
 } io_mapping_t;

 typedef struct sel4platsupport_io_mapper_cookie {
     vspace_t *vspace;
     vka_t *vka;
     io_mapping_t *head;
 } sel4platsupport_io_mapper_cookie_t;

 static void free_node(io_mapping_t *node)
 {
     assert(node);
     if (node->caps) {
         free(node->caps);
     }
     if (node->alloc_cookies) {
         free(node->alloc_cookies);
     }
     free(node);
 }

 static io_mapping_t *new_node(size_t num_pages)
 {
     io_mapping_t *ret = calloc(1, sizeof(io_mapping_t));

     if (!ret) {
         return NULL;
     }

     ret->caps = calloc(num_pages, sizeof(seL4_CPtr));
     if (!ret->caps) {
         free_node(ret);
         return NULL;
     }

     ret->alloc_cookies = calloc(num_pages, sizeof(seL4_Word));
     if (!ret->alloc_cookies) {
         free_node(ret);
         return NULL;
     }

     ret->num_pages = num_pages;
     return ret;
 }

 static void destroy_node(vka_t *vka, io_mapping_t *mapping)
 {
     cspacepath_t path;
     for (size_t i = 0; i < mapping->num_pages; i++) {
         /* free the allocation */
         vka_utspace_free(vka, kobject_get_type(KOBJECT_FRAME, mapping->page_size_bits),
                          mapping->page_size_bits, mapping->alloc_cookies[i]);
         /* free the caps */
         vka_cspace_make_path(vka, mapping->caps[i], &path);
         vka_cnode_delete(&path);
         vka_cspace_free(vka, mapping->caps[i]);
     }
     free_node(mapping);
 }

 static void insert_node(sel4platsupport_io_mapper_cookie_t *io_mapper, io_mapping_t *node)
 {
     node->prev = NULL;
     node->next = io_mapper->head;
     if (io_mapper->head) {
         io_mapper->head->prev = node;
     }
     io_mapper->head = node;
 }

 static io_mapping_t *find_node(sel4platsupport_io_mapper_cookie_t *io_mapper, void *returned_addr)
 {
     io_mapping_t *current;
     for (current = io_mapper->head; current; current = current->next) {
         if (current->returned_addr == returned_addr) {
             return current;
         }
     }
     return NULL;
 }

 static void remove_node(sel4platsupport_io_mapper_cookie_t *io_mapper, io_mapping_t *node)
 {
     if (node->prev) {
         node->prev->next = node->next;
     } else {
         assert(io_mapper->head == node);
         io_mapper->head = node->next;
     }
     if (node->next) {
         node->next->prev = node->prev;
     }
 }

 static void *sel4platsupport_map_paddr_with_page_size(sel4platsupport_io_mapper_cookie_t *io_mapper, uintptr_t paddr,
                                                       size_t size, size_t page_size_bits, bool cached)
 {

     vka_t *vka = io_mapper->vka;
     vspace_t *vspace = io_mapper->vspace;

     /* search at start of page */
     int page_size = BIT(page_size_bits);
     uintptr_t start = ROUND_DOWN(paddr, page_size);
     uintptr_t offset = paddr - start;
     size += offset;

     io_mapping_t *mapping = new_node(BYTES_TO_SIZE_BITS_PAGES(size, page_size_bits));
     assert(mapping->num_pages << page_size_bits >= size);
     if (!mapping) {
         ZF_LOGE("Failed to allocate node for %zu pages", mapping->num_pages);
         return NULL;
     }
     mapping->page_size_bits = page_size_bits;

     seL4_Word type = kobject_get_type(KOBJECT_FRAME, mapping->page_size_bits);
     /* allocate all of the physical frame caps */
     for (unsigned int i = 0; i < mapping->num_pages; i++) {
         /* allocate a cslot */
         int error = vka_cspace_alloc(vka, &mapping->caps[i]);
         if (error) {
             ZF_LOGE("cspace alloc failed");
             assert(error == 0);
             /* we don't clean up as everything has gone to hell */
             return NULL;
         }

         /* create a path */
         cspacepath_t path;
         vka_cspace_make_path(vka, mapping->caps[i], &path);

         /* allocate the frame */
         error = vka_utspace_alloc_at(vka, &path, type, page_size_bits, start + (i * page_size),
                                      &mapping->alloc_cookies[i]);
         if (error) {
             /* free this slot, and then do general cleanup of the rest of the slots.
              * this avoids a needless seL4_CNode_Delete of this slot, as there is no
              * cap in it */
             vka_cspace_free(vka, mapping->caps[i]);
             mapping->num_pages = i;
             goto error;
         }
     }

     /* Now map the frames in */
     mapping->mapped_addr = vspace_map_pages(vspace, mapping->caps, mapping->alloc_cookies, seL4_AllRights,
                                             mapping->num_pages,
                                             mapping->page_size_bits, cached);
     if (mapping->mapped_addr != NULL) {
         /* fill out and insert node */
         mapping->returned_addr = mapping->mapped_addr + offset;
         insert_node(io_mapper, mapping);
         return mapping->returned_addr;
     }
 error:
     destroy_node(vka, mapping);
     return NULL;
 }

 static void *sel4platsupport_map_paddr(void *cookie, uintptr_t paddr, size_t size, int cached,
                                        UNUSED ps_mem_flags_t flags)
 {
     if (!cookie) {
         ZF_LOGE("cookie is NULL");
         return NULL;
     }

     sel4platsupport_io_mapper_cookie_t *io_mapper = (sel4platsupport_io_mapper_cookie_t *)cookie;
     int frame_size_index = 0;
     /* find the largest reasonable frame size */
     while (frame_size_index + 1 < SEL4_NUM_PAGE_SIZES) {
         if (size >> sel4_page_sizes[frame_size_index + 1] == 0) {
             break;
         }
         frame_size_index++;
     }

     /* try mapping in this and all smaller frame sizes until something works */
     for (int i = frame_size_index; i >= 0; i--) {
         void *result = sel4platsupport_map_paddr_with_page_size(io_mapper, paddr, size, sel4_page_sizes[i], cached);
         if (result) {
             return result;
         }
     }

     /* shit out of luck */
     ZF_LOGE("Failed to find a way to map address %p", (void *)paddr);
     return NULL;
 }

 static void sel4platsupport_unmap_vaddr(void *cookie, void *vaddr, UNUSED size_t size)
 {
     if (!cookie) {
         ZF_LOGE("cookie is NULL");
     }

     sel4platsupport_io_mapper_cookie_t *io_mapper = cookie;

     vspace_t *vspace = io_mapper->vspace;
     vka_t *vka = io_mapper->vka;
     io_mapping_t *mapping = find_node(io_mapper, vaddr);

     if (!mapping) {
         ZF_LOGF("Tried to unmap vaddr %p, which was never mapped in", vaddr);
         return;
     }

     /* unmap the pages */
     vspace_unmap_pages(vspace, mapping->mapped_addr, mapping->num_pages, mapping->page_size_bits,
                        VSPACE_PRESERVE);

     /* clean up the node */
     remove_node(io_mapper, mapping);
     destroy_node(vka, mapping);
 }

 int sel4platsupport_new_io_mapper(vspace_t *vspace, vka_t *vka, ps_io_mapper_t *io_mapper)
 {
     sel4platsupport_io_mapper_cookie_t *cookie = calloc(1, sizeof(sel4platsupport_io_mapper_cookie_t));
     if (!cookie) {
         ZF_LOGE("Failed to allocate %zu bytes", sizeof(sel4platsupport_io_mapper_cookie_t));
         return -1;
     }

     cookie->vspace = vspace;
     cookie->vka = vka;
     io_mapper->cookie = cookie;
     io_mapper->io_map_fn = sel4platsupport_map_paddr;
     io_mapper->io_unmap_fn = sel4platsupport_unmap_vaddr;

     return 0;
 }

 int sel4platsupport_new_malloc_ops(ps_malloc_ops_t *ops)
 {
     ps_new_stdlib_malloc_ops(ops);
     return 0;
 }

 static char *sel4platsupport_io_fdt_get(void *cookie)
 {
     return cookie != NULL ? (char *) cookie : NULL;
 }

 int sel4platsupport_new_fdt_ops(ps_io_fdt_t *io_fdt, simple_t *simple, ps_malloc_ops_t *malloc_ops)
 {
     if (!io_fdt || !simple || !malloc_ops) {
         ZF_LOGE("arguments are NULL");
         return -1;
     }

     ssize_t block_size = simple_get_extended_bootinfo_length(simple, SEL4_BOOTINFO_HEADER_FDT);
     if (block_size > 0) {
         int error = ps_calloc(malloc_ops, 1, block_size, &io_fdt->cookie);
         if (error) {
             ZF_LOGE("Failed to allocate %zu bytes for the FDT", block_size);
             return -1;
         }

         /* Copy the FDT from the extended bootinfo */
         ssize_t copied_size = simple_get_extended_bootinfo(simple, SEL4_BOOTINFO_HEADER_FDT,
                                                            io_fdt->cookie, block_size);
         if (copied_size != block_size) {
             ZF_LOGE("Failed to copy the FDT");
             ZF_LOGF_IF(ps_free(malloc_ops, block_size, io_fdt->cookie),
                        "Failed to clean-up after a failed operation!");
             return -1;
         }

         /* Cut off the bootinfo header from the start of the buffer */
         ssize_t fdt_size = block_size - sizeof(seL4_BootInfoHeader);
         void *fdt_start = io_fdt->cookie + sizeof(seL4_BootInfoHeader);
         memmove(io_fdt->cookie, fdt_start, fdt_size);

         /* Trim off the extra bytes at the end of the FDT */
         void *fdt_end = io_fdt->cookie + fdt_size;
         memset(fdt_end, 0, sizeof(seL4_BootInfoHeader));
     } else {
         /* No FDT is available so just set the cookie to NULL */
         io_fdt->cookie = NULL;
     }

     /* Set the function pointer inside the io_fdt interface */
     io_fdt->get_fn = sel4platsupport_io_fdt_get;

     return 0;
 }

 #ifdef CONFIG_PLAT_TK1
 #include <platsupport/gpio.h>

 gpio_sys_t gpio_sys;
 #endif

 void *get_mux_dependencies(void)
 {
 #ifdef CONFIG_PLAT_TK1
     /* The TK1's mux depends on an instance of the GPIO driver. */
     return &gpio_sys;
 #else
     /* The other platforms don't have any such dependency issues. */
     return NULL;
 #endif
 }

 int sel4platsupport_new_io_ops(vspace_t *vspace, vka_t *vka, simple_t *simple, ps_io_ops_t *io_ops)
 {
     memset(io_ops, 0, sizeof(ps_io_ops_t));

     int error = 0;

     /* Initialise the interfaces which do not require memory allocation/need to be initialised first */
     error = sel4platsupport_new_malloc_ops(&io_ops->malloc_ops)
 #ifdef ARCH_ARM
             || clock_sys_init(io_ops, &io_ops->clock_sys)
 #ifdef CONFIG_PLAT_TK1
             || gpio_sys_init(io_ops, &gpio_sys)
 #endif
             || mux_sys_init(io_ops, get_mux_dependencies(), &io_ops->mux_sys)
 #endif
             ;
     if (error) {
         return error;
     }

     /* Now allocate the IO-specific interfaces (the ones that can be found in this file) */
     error = sel4platsupport_new_io_mapper(vspace, vka, &io_ops->io_mapper);
     if (error) {
         return error;
     }

     error = sel4platsupport_new_fdt_ops(&io_ops->io_fdt, simple, &io_ops->malloc_ops);
     if (error) {
         free(io_ops->io_mapper.cookie);
         io_ops->io_mapper.cookie = NULL;
         return error;
     }

     error = sel4platsupport_new_irq_ops(&io_ops->irq_ops, vka, simple, DEFAULT_IRQ_INTERFACE_CONFIG,
                                         &io_ops->malloc_ops);
     if (error) {
         free(io_ops->io_mapper.cookie);
         io_ops->io_mapper.cookie = NULL;
         ssize_t fdt_size = simple_get_extended_bootinfo_length(simple, SEL4_BOOTINFO_HEADER_FDT);
         if (fdt_size > 0) {
             /* The FDT is available on this platform and we actually copied it, so we free it */
             ps_free(&io_ops->malloc_ops, fdt_size, &io_ops->io_fdt.cookie);
         }
         return error;
     }

     return 0;
 }
	/*
	* Copyright 2017, Data61
	* Commonwealth Scientific and Industrial Research Organisation (CSIRO)
	* ABN 41 687 119 230.
	*
	* This software may be distributed and modified according to the terms of
	* the BSD 2-Clause license. Note that NO WARRANTY is provided.
	* See "LICENSE_BSD2.txt" for details.
	*
	* @TAG(DATA61_BSD)
	*/

	#include <autoconf.h>
	#include <sel4platsupport/gen_config.h>

	#include <sel4platsupport/io.h>
	#ifdef CONFIG_ARCH_ARM
	#include <platsupport/clock.h>
	#include <platsupport/mux.h>
	#endif
	#include <utils/util.h>
	#include <vspace/page.h>

	#include <vspace/vspace.h>
	#include <vka/capops.h>

	#include <stdint.h>
	#include <stdlib.h>

	typedef struct io_mapping {
	/* address we returned to the user */
	void *returned_addr;
	/* base address of the mapping with respect to the vspace */
	void *mapped_addr;
	size_t num_pages;
	size_t page_size;
	size_t page_size_bits;
	/* caps for the mappings (s) */
	seL4_CPtr *caps;
	/* allocation cookie for allocation(s) */
	seL4_Word *alloc_cookies;
	struct io_mapping next, prev;
	} io_mapping_t;

	typedef struct sel4platsupport_io_mapper_cookie {
	vspace_t *vspace;
	vka_t *vka;
	io_mapping_t *head;
	} sel4platsupport_io_mapper_cookie_t;

	static void free_node(io_mapping_t *node)
	{
	assert(node);
	if (node->caps) {
	free(node->caps);
	}
	if (node->alloc_cookies) {
	free(node->alloc_cookies);
	}
	free(node);
	}

	static io_mapping_t *new_node(size_t num_pages)
	{
	io_mapping_t *ret = calloc(1, sizeof(io_mapping_t));

	if (!ret) {
	return NULL;
	}

	ret->caps = calloc(num_pages, sizeof(seL4_CPtr));
	if (!ret->caps) {
	free_node(ret);
	return NULL;
	}

	ret->alloc_cookies = calloc(num_pages, sizeof(seL4_Word));
	if (!ret->alloc_cookies) {
	free_node(ret);
	return NULL;
	}

	ret->num_pages = num_pages;
	return ret;
	}

	static void destroy_node(vka_t vka, io_mapping_t mapping)
	{
	cspacepath_t path;
	for (size_t i = 0; i < mapping->num_pages; i++) {
	/* free the allocation */
	vka_utspace_free(vka, kobject_get_type(KOBJECT_FRAME, mapping->page_size_bits),
	mapping->page_size_bits, mapping->alloc_cookies[i]);
	/* free the caps */
	vka_cspace_make_path(vka, mapping->caps[i], &path);
	vka_cnode_delete(&path);
	vka_cspace_free(vka, mapping->caps[i]);
	}
	free_node(mapping);
	}

	static void insert_node(sel4platsupport_io_mapper_cookie_t io_mapper, io_mapping_t node)
	{
	node->prev = NULL;
	node->next = io_mapper->head;
	if (io_mapper->head) {
	io_mapper->head->prev = node;
	}
	io_mapper->head = node;
	}

	static io_mapping_t find_node(sel4platsupport_io_mapper_cookie_t io_mapper, void *returned_addr)
	{
	io_mapping_t *current;
	for (current = io_mapper->head; current; current = current->next) {
	if (current->returned_addr == returned_addr) {
	return current;
	}
	}
	return NULL;
	}

	static void remove_node(sel4platsupport_io_mapper_cookie_t io_mapper, io_mapping_t node)
	{
	if (node->prev) {
	node->prev->next = node->next;
	} else {
	assert(io_mapper->head == node);
	io_mapper->head = node->next;
	}
	if (node->next) {
	node->next->prev = node->prev;
	}
	}

	static void sel4platsupport_map_paddr_with_page_size(sel4platsupport_io_mapper_cookie_t io_mapper, uintptr_t paddr,
	size_t size, size_t page_size_bits, bool cached)
	{

	vka_t *vka = io_mapper->vka;
	vspace_t *vspace = io_mapper->vspace;

	/* search at start of page */
	int page_size = BIT(page_size_bits);
	uintptr_t start = ROUND_DOWN(paddr, page_size);
	uintptr_t offset = paddr - start;
	size += offset;

	io_mapping_t *mapping = new_node(BYTES_TO_SIZE_BITS_PAGES(size, page_size_bits));
	assert(mapping->num_pages << page_size_bits >= size);
	if (!mapping) {
	ZF_LOGE("Failed to allocate node for %zu pages", mapping->num_pages);
	return NULL;
	}
	mapping->page_size_bits = page_size_bits;

	seL4_Word type = kobject_get_type(KOBJECT_FRAME, mapping->page_size_bits);
	/* allocate all of the physical frame caps */
	for (unsigned int i = 0; i < mapping->num_pages; i++) {
	/* allocate a cslot */
	int error = vka_cspace_alloc(vka, &mapping->caps[i]);
	if (error) {
	ZF_LOGE("cspace alloc failed");
	assert(error == 0);
	/* we don't clean up as everything has gone to hell */
	return NULL;
	}

	/* create a path */
	cspacepath_t path;
	vka_cspace_make_path(vka, mapping->caps[i], &path);

	/* allocate the frame */
	error = vka_utspace_alloc_at(vka, &path, type, page_size_bits, start + (i * page_size),
	&mapping->alloc_cookies[i]);
	if (error) {
	/* free this slot, and then do general cleanup of the rest of the slots.
	* this avoids a needless seL4_CNode_Delete of this slot, as there is no
	* cap in it */
	vka_cspace_free(vka, mapping->caps[i]);
	mapping->num_pages = i;
	goto error;
	}
	}

	/* Now map the frames in */
	mapping->mapped_addr = vspace_map_pages(vspace, mapping->caps, mapping->alloc_cookies, seL4_AllRights,
	mapping->num_pages,
	mapping->page_size_bits, cached);
	if (mapping->mapped_addr != NULL) {
	/* fill out and insert node */
	mapping->returned_addr = mapping->mapped_addr + offset;
	insert_node(io_mapper, mapping);
	return mapping->returned_addr;
	}
	error:
	destroy_node(vka, mapping);
	return NULL;
	}

	static void sel4platsupport_map_paddr(void cookie, uintptr_t paddr, size_t size, int cached,
	UNUSED ps_mem_flags_t flags)
	{
	if (!cookie) {
	ZF_LOGE("cookie is NULL");
	return NULL;
	}

	sel4platsupport_io_mapper_cookie_t io_mapper = (sel4platsupport_io_mapper_cookie_t )cookie;
	int frame_size_index = 0;
	/* find the largest reasonable frame size */
	while (frame_size_index + 1 < SEL4_NUM_PAGE_SIZES) {
	if (size >> sel4_page_sizes[frame_size_index + 1] == 0) {
	break;
	}
	frame_size_index++;
	}

	/* try mapping in this and all smaller frame sizes until something works */
	for (int i = frame_size_index; i >= 0; i--) {
	void *result = sel4platsupport_map_paddr_with_page_size(io_mapper, paddr, size, sel4_page_sizes[i], cached);
	if (result) {
	return result;
	}
	}

	/* shit out of luck */
	ZF_LOGE("Failed to find a way to map address %p", (void *)paddr);
	return NULL;
	}

	static void sel4platsupport_unmap_vaddr(void cookie, void vaddr, UNUSED size_t size)
	{
	if (!cookie) {
	ZF_LOGE("cookie is NULL");
	}

	sel4platsupport_io_mapper_cookie_t *io_mapper = cookie;

	vspace_t *vspace = io_mapper->vspace;
	vka_t *vka = io_mapper->vka;
	io_mapping_t *mapping = find_node(io_mapper, vaddr);

	if (!mapping) {
	ZF_LOGF("Tried to unmap vaddr %p, which was never mapped in", vaddr);
	return;
	}

	/* unmap the pages */
	vspace_unmap_pages(vspace, mapping->mapped_addr, mapping->num_pages, mapping->page_size_bits,
	VSPACE_PRESERVE);

	/* clean up the node */
	remove_node(io_mapper, mapping);
	destroy_node(vka, mapping);
	}

	int sel4platsupport_new_io_mapper(vspace_t vspace, vka_t vka, ps_io_mapper_t *io_mapper)
	{
	sel4platsupport_io_mapper_cookie_t *cookie = calloc(1, sizeof(sel4platsupport_io_mapper_cookie_t));
	if (!cookie) {
	ZF_LOGE("Failed to allocate %zu bytes", sizeof(sel4platsupport_io_mapper_cookie_t));
	return -1;
	}

	cookie->vspace = vspace;
	cookie->vka = vka;
	io_mapper->cookie = cookie;
	io_mapper->io_map_fn = sel4platsupport_map_paddr;
	io_mapper->io_unmap_fn = sel4platsupport_unmap_vaddr;

	return 0;
	}

	int sel4platsupport_new_malloc_ops(ps_malloc_ops_t *ops)
	{
	ps_new_stdlib_malloc_ops(ops);
	return 0;
	}

	static char sel4platsupport_io_fdt_get(void cookie)
	{
	return cookie != NULL ? (char *) cookie : NULL;
	}

	int sel4platsupport_new_fdt_ops(ps_io_fdt_t io_fdt, simple_t simple, ps_malloc_ops_t *malloc_ops)
	{
	if (!io_fdt \|\| !simple \|\| !malloc_ops) {
	ZF_LOGE("arguments are NULL");
	return -1;
	}

	ssize_t block_size = simple_get_extended_bootinfo_length(simple, SEL4_BOOTINFO_HEADER_FDT);
	if (block_size > 0) {
	int error = ps_calloc(malloc_ops, 1, block_size, &io_fdt->cookie);
	if (error) {
	ZF_LOGE("Failed to allocate %zu bytes for the FDT", block_size);
	return -1;
	}

	/* Copy the FDT from the extended bootinfo */
	ssize_t copied_size = simple_get_extended_bootinfo(simple, SEL4_BOOTINFO_HEADER_FDT,
	io_fdt->cookie, block_size);
	if (copied_size != block_size) {
	ZF_LOGE("Failed to copy the FDT");
	ZF_LOGF_IF(ps_free(malloc_ops, block_size, io_fdt->cookie),
	"Failed to clean-up after a failed operation!");
	return -1;
	}

	/* Cut off the bootinfo header from the start of the buffer */
	ssize_t fdt_size = block_size - sizeof(seL4_BootInfoHeader);
	void *fdt_start = io_fdt->cookie + sizeof(seL4_BootInfoHeader);
	memmove(io_fdt->cookie, fdt_start, fdt_size);

	/* Trim off the extra bytes at the end of the FDT */
	void *fdt_end = io_fdt->cookie + fdt_size;
	memset(fdt_end, 0, sizeof(seL4_BootInfoHeader));
	} else {
	/* No FDT is available so just set the cookie to NULL */
	io_fdt->cookie = NULL;
	}

	/* Set the function pointer inside the io_fdt interface */
	io_fdt->get_fn = sel4platsupport_io_fdt_get;

	return 0;
	}

	#ifdef CONFIG_PLAT_TK1
	#include <platsupport/gpio.h>

	gpio_sys_t gpio_sys;
	#endif

	void *get_mux_dependencies(void)
	{
	#ifdef CONFIG_PLAT_TK1
	/* The TK1's mux depends on an instance of the GPIO driver. */
	return &gpio_sys;
	#else
	/* The other platforms don't have any such dependency issues. */
	return NULL;
	#endif
	}

	int sel4platsupport_new_io_ops(vspace_t vspace, vka_t vka, simple_t simple, ps_io_ops_t io_ops)
	{
	memset(io_ops, 0, sizeof(ps_io_ops_t));

	int error = 0;

	/* Initialise the interfaces which do not require memory allocation/need to be initialised first */
	error = sel4platsupport_new_malloc_ops(&io_ops->malloc_ops)
	#ifdef ARCH_ARM
	\|\| clock_sys_init(io_ops, &io_ops->clock_sys)
	#ifdef CONFIG_PLAT_TK1
	\|\| gpio_sys_init(io_ops, &gpio_sys)
	#endif
	\|\| mux_sys_init(io_ops, get_mux_dependencies(), &io_ops->mux_sys)
	#endif
	;
	if (error) {
	return error;
	}

	/* Now allocate the IO-specific interfaces (the ones that can be found in this file) */
	error = sel4platsupport_new_io_mapper(vspace, vka, &io_ops->io_mapper);
	if (error) {
	return error;
	}

	error = sel4platsupport_new_fdt_ops(&io_ops->io_fdt, simple, &io_ops->malloc_ops);
	if (error) {
	free(io_ops->io_mapper.cookie);
	io_ops->io_mapper.cookie = NULL;
	return error;
	}

	error = sel4platsupport_new_irq_ops(&io_ops->irq_ops, vka, simple, DEFAULT_IRQ_INTERFACE_CONFIG,
	&io_ops->malloc_ops);
	if (error) {
	free(io_ops->io_mapper.cookie);
	io_ops->io_mapper.cookie = NULL;
	ssize_t fdt_size = simple_get_extended_bootinfo_length(simple, SEL4_BOOTINFO_HEADER_FDT);
	if (fdt_size > 0) {
	/* The FDT is available on this platform and we actually copied it, so we free it */
	ps_free(&io_ops->malloc_ops, fdt_size, &io_ops->io_fdt.cookie);
	}
	return error;
	}

	return 0;
	}