u-boot/arch/sandbox/cpu/mem.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (c) 2011 The Chromium OS Authors.
 * Copyright 2025 Simon Glass <sjg@chromium.org>
 */

#define LOG_CATEGORY	LOGC_SANDBOX

#include <alist.h>
#include <errno.h>
#include <log.h>
#include <malloc.h>
#include <os.h>
#include <asm/global_data.h>
#include <asm/io.h>
#include <asm/sandbox_pci.h>
#include <asm/state.h>
#include <linux/list.h>

DECLARE_GLOBAL_DATA_PTR;

/* Enable access to PCI memory with map_sysmem() */
static bool enable_pci_map;

#ifdef CONFIG_PCI
/* Last device that was mapped into memory, and length of mapping */
static struct udevice *map_dev;
unsigned long map_len;
#endif

/**
 * is_in_sandbox_mem() - Checks if a pointer is within sandbox's emulated DRAM
 *
 * This provides a way to check if a pointer is owned by sandbox (and is within
 * its RAM) or not. Sometimes pointers come from a test which conceptually runs
 * output sandbox, potentially with direct access to the C-library malloc()
 * function, or the sandbox stack (which is not actually within the emulated
 * DRAM.
 *
 * Such pointers obviously cannot be mapped into sandbox's DRAM, so we must
 * detect them an process them separately, by recording a mapping to a tag,
 * which we can use to map back to the pointer later.
 *
 * @ptr: Pointer to check
 * Return: true if this is within sandbox emulated DRAM, false if not
 */
static bool is_in_sandbox_mem(const void *ptr)
{
	return (const uint8_t *)ptr >= gd->arch.ram_buf &&
		(const uint8_t *)ptr < gd->arch.ram_buf + gd->ram_size;
}

/**
 * phys_to_virt() - Converts a sandbox RAM address to a pointer
 *
 * Sandbox uses U-Boot addresses from 0 to the size of DRAM. These index into
 * the emulated DRAM buffer used by sandbox. This function converts such an
 * address to a pointer into this buffer, which can be used to access the
 * memory.
 *
 * If the address is outside this range, it is assumed to be a tag
 */
void *phys_to_virt(phys_addr_t paddr)
{
	struct sandbox_mapmem_entry *mentry;
	struct sandbox_state *state;

	/* If the address is within emulated DRAM, calculate the value */
	if (paddr < gd->ram_size)
		return (void *)(gd->arch.ram_buf + paddr);

	/*
	 * Otherwise search out list of tags for the correct pointer previously
	 * created by map_to_sysmem()
	 */
	state = state_get_current();
	list_for_each_entry(mentry, &state->mapmem_head, sibling_node) {
		if (mentry->tag == paddr) {
			log_debug("Used map from %lx to %p\n", (ulong)paddr,
				  mentry->ptr);
			mentry->refcnt++;
			return mentry->ptr;
		}
	}

	printf("%s: Cannot map sandbox address %lx (SDRAM from 0 to %lx)\n",
	       __func__, (ulong)paddr, (ulong)gd->ram_size);
	os_abort();

	/* Not reached */
	return NULL;
}

struct sandbox_mapmem_entry *find_tag(const void *ptr)
{
	struct sandbox_mapmem_entry *mentry;
	struct sandbox_state *state = state_get_current();

	list_for_each_entry(mentry, &state->mapmem_head, sibling_node) {
		if (mentry->ptr == ptr) {
			log_debug("Used map from %p to %lx\n", ptr,
				  mentry->tag);
			return mentry;
		}
	}

	return NULL;
}

phys_addr_t virt_to_phys(void *ptr)
{
	struct sandbox_mapmem_entry *mentry;

	/*
	 * If it is in emulated RAM, don't bother looking for a tag. Just
	 * calculate the pointer using the provides offset into the RAM buffer.
	 */
	if (is_in_sandbox_mem(ptr))
		return (phys_addr_t)((uint8_t *)ptr - gd->arch.ram_buf);

	mentry = find_tag(ptr);
	if (!mentry) {
		/* Abort so that gdb can be used here */
		printf("%s: Cannot map sandbox address %p (SDRAM from 0 to %lx)\n",
		       __func__, ptr, (ulong)gd->ram_size);
		os_abort();
	}
	log_debug("Used map from %p to %lx\n", ptr, mentry->tag);

	return mentry->tag;
}

void *map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
{
#if defined(CONFIG_PCI) && !defined(CONFIG_XPL_BUILD)
	unsigned long plen = len;
	void *ptr;

	map_dev = NULL;
	if (enable_pci_map && !pci_map_physmem(paddr, &len, &map_dev, &ptr)) {
		if (plen != len) {
			/*
			 * This may actually be harmless, but since this feature
			 * is only used in tests, it is better to fix the text
			 * to request the correct size. Aborting here enables
			 * use of gdb to figure out what went wrong. It may mask
			 * a very hard-to-debug problem, if sandbox's RAM is
			 * inadvertently mapped in.
			 */
			printf("%s: Fatal: partial map at %x, wanted %lx, got %lx\n",
			       __func__, (uint)paddr, plen, len);
			os_abort();
		}
		map_len = len;
		log_debug("pci map %lx -> %p\n", (ulong)paddr, ptr);
		return ptr;
	}
#endif

	return phys_to_virt(paddr);
}

void unmap_physmem(const void *ptr, unsigned long flags)
{
	struct sandbox_mapmem_entry *mentry;

#ifdef CONFIG_PCI
	if (map_dev) {
		pci_unmap_physmem(ptr, map_len, map_dev);
		map_dev = NULL;
	}
#endif

	/* If it is in emulated RAM, we didn't create a tag, so nothing to do */
	if (is_in_sandbox_mem(ptr))
		return;

	mentry = find_tag(ptr);
	if (mentry) {
		if (!--mentry->refcnt) {
			list_del(&mentry->sibling_node);
			log_debug("Removed map from %p to %lx\n", ptr,
				  (ulong)mentry->tag);
			free(mentry);
		}
	} else {
		log_warning("Address not mapped: %p\n", ptr);
	}
}

phys_addr_t map_to_sysmem(const void *ptr)
{
	struct sandbox_mapmem_entry *mentry;

	/*
	 * If it is in emulated RAM, don't bother creating a tag. Just return
	 * the offset into the RAM buffer.
	 */
	if (is_in_sandbox_mem(ptr))
		return (u8 *)ptr - gd->arch.ram_buf;

	/*
	 * See if there is an existing tag with this pointer. If not, set up a
	 * new one.
	 */
	mentry = find_tag(ptr);
	if (!mentry) {
		struct sandbox_state *state = state_get_current();

		mentry = malloc(sizeof(*mentry));
		if (!mentry) {
			printf("%s: Error: Out of memory\n", __func__);
			os_exit(ENOMEM);
		}
		mentry->tag = state->next_tag++;
		mentry->ptr = (void *)ptr;
		mentry->refcnt = 0;
		list_add_tail(&mentry->sibling_node, &state->mapmem_head);
		log_debug("Added map from %p to %lx\n", ptr,
			  (ulong)mentry->tag);
	}

	mentry->refcnt++;

	/*
	 * Return the tag as the address to use. A later call to map_sysmem()
	 * will return ptr
	 */
	return mentry->tag;
}

void sandbox_map_list(void)
{
	struct sandbox_mapmem_entry *mentry;
	struct sandbox_state *state = state_get_current();

	printf("Sandbox memory-mapping\n");
	printf("%8s  %16s  %6s\n", "Addr", "Mapping", "Refcnt");
	list_for_each_entry(mentry, &state->mapmem_head, sibling_node) {
		printf("%8lx  %p  %6d\n", mentry->tag, mentry->ptr,
		       mentry->refcnt);
	}
}

static bool in_range(const struct sandbox_mmio *mmio, const void *addr)
{
	return addr >= mmio->base && addr < mmio->base + mmio->size;
}

unsigned long sandbox_read(const void *addr, enum sandboxio_size_t size)
{
	struct sandbox_state *state = state_get_current();
	const struct sandbox_mmio *mmio;

	alist_for_each(mmio, &state->mmio) {
		if (in_range(mmio, addr))
			return mmio->h_read(mmio->ctx, addr, size);
	}

	if (!state->allow_memio)
		return 0;

	switch (size) {
	case SB_SIZE_8:
		return *(u8 *)addr;
	case SB_SIZE_16:
		return *(u16 *)addr;
	case SB_SIZE_32:
		return *(u32 *)addr;
	case SB_SIZE_64:
		return *(u64 *)addr;
	}

	return 0;
}

void sandbox_write(void *addr, unsigned int val, enum sandboxio_size_t size)
{
	struct sandbox_state *state = state_get_current();
	const struct sandbox_mmio *mmio;

	alist_for_each(mmio, &state->mmio) {
		if (in_range(mmio, addr)) {
			mmio->h_write(mmio->ctx, addr, val, size);
			return;
		}
	}

	if (!state->allow_memio)
		return;

	switch (size) {
	case SB_SIZE_8:
		*(u8 *)addr = val;
		break;
	case SB_SIZE_16:
		*(u16 *)addr = val;
		break;
	case SB_SIZE_32:
		*(u32 *)addr = val;
		break;
	case SB_SIZE_64:
		*(u64 *)addr = val;
		break;
	}
}

void sandbox_set_enable_memio(bool enable)
{
	struct sandbox_state *state = state_get_current();

	state->allow_memio = enable;
}

void sandbox_set_enable_pci_map(int enable)
{
	enable_pci_map = enable;
}

int sandbox_mmio_add(void *base, ulong size, sandbox_mmio_read_func h_read,
		     sandbox_mmio_write_func h_write, void *ctx)
{
	struct sandbox_state *state = state_get_current();
	struct sandbox_mmio mmio;

	mmio.base = base;
	mmio.size = size;
	mmio.h_read = h_read;
	mmio.h_write = h_write;
	mmio.ctx = ctx;
	if (!alist_add(&state->mmio, mmio))
		return -ENOMEM;

	return 0;
}

void sandbox_mmio_remove(void *ctx)
{
	struct sandbox_state *state = state_get_current();
	struct sandbox_mmio *from, *to;

	alist_for_each_filter(from, to, &state->mmio) {
		if (from->ctx != ctx)
			*to++ = *from;
	}
	alist_update_end(&state->mmio, to);
}