sandbox: Allow use of real I/O with readl(), etc.

At present these functions are stubbed out. For more comprehensive testing
with PCI devices it is useful to be able to fully emulate I/O access. Add
simple implementations for these.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: change to use 'const void *' in sandbox_write();
        cast 'addr' in read/write macros in arch/sandbox/include/asm/io.h;
        remove the unnecessary cast in readq/writeq in nvme.h]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

arch/sandbox/cpu/cpu.c

@@ -225,6 +225,58 @@ phys_addr_t map_to_sysmem(const void *ptr)
 	return mentry->tag;
 }
 
+unsigned int sandbox_read(const void *addr, enum sandboxio_size_t size)
+{
+	struct sandbox_state *state = state_get_current();
+
+	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(const void *addr, unsigned int val,
+		   enum sandboxio_size_t size)
+{
+	struct sandbox_state *state = state_get_current();
+
+	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;

arch/sandbox/include/asm/io.h

@@ -6,6 +6,13 @@
 #ifndef __SANDBOX_ASM_IO_H
 #define __SANDBOX_ASM_IO_H
 
+enum sandboxio_size_t {
+	SB_SIZE_8,
+	SB_SIZE_16,
+	SB_SIZE_32,
+	SB_SIZE_64,
+};
+
 void *phys_to_virt(phys_addr_t paddr);
 #define phys_to_virt phys_to_virt
 
@@ -38,18 +45,21 @@ static inline void unmap_sysmem(const void *vaddr)
 /* Map from a pointer to our RAM buffer */
 phys_addr_t map_to_sysmem(const void *ptr);
 
-/* Define nops for sandbox I/O access */
-#define readb(addr) ((void)addr, 0)
-#define readw(addr) ((void)addr, 0)
-#define readl(addr) ((void)addr, 0)
+unsigned int sandbox_read(const void *addr, enum sandboxio_size_t size);
+void sandbox_write(const void *addr, unsigned int val,
+		   enum sandboxio_size_t size);
+
+#define readb(addr) sandbox_read((const void *)addr, SB_SIZE_8)
+#define readw(addr) sandbox_read((const void *)addr, SB_SIZE_16)
+#define readl(addr) sandbox_read((const void *)addr, SB_SIZE_32)
 #ifdef CONFIG_SANDBOX64
-#define readq(addr) ((void)addr, 0)
+#define readq(addr) sandbox_read((const void *)addr, SB_SIZE_64)
 #endif
-#define writeb(v, addr) ((void)addr)
-#define writew(v, addr) ((void)addr)
-#define writel(v, addr) ((void)addr)
+#define writeb(v, addr) sandbox_write((const void *)addr, v, SB_SIZE_8)
+#define writew(v, addr) sandbox_write((const void *)addr, v, SB_SIZE_16)
+#define writel(v, addr) sandbox_write((const void *)addr, v, SB_SIZE_32)
 #ifdef CONFIG_SANDBOX64
-#define writeq(v, addr) ((void)addr)
+#define writeq(v, addr) sandbox_write((const void *)addr, v, SB_SIZE_64)
 #endif
 
 /*

arch/sandbox/include/asm/state.h

@@ -102,6 +102,7 @@ struct sandbox_state {
 	ulong next_tag;			/* Next address tag to allocate */
 	struct list_head mapmem_head;	/* struct sandbox_mapmem_entry */
 	bool hwspinlock;		/* Hardware Spinlock status */
+	bool allow_memio;		/* Allow readl() etc. to work */
 
 	/*
 	 * This struct is getting large.