sandbox: Add PCI driver and test for p2sb

Add a sandbox driver and PCI-device emulator for p2sb. Also add a test
which uses a simple 'adder' driver to test the p2sb functionality.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/misc/p2sb_emul.c b/drivers/misc/p2sb_emul.c
new file mode 100644
index 0000000..c3795c5
--- /dev/null
+++ b/drivers/misc/p2sb_emul.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * PCI emulation device for an x86 Primary-to-Sideband bus
+ *
+ * Copyright 2019 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#define LOG_CATEGORY UCLASS_MISC
+#define LOG_DEBUG
+
+#include <common.h>
+#include <axi.h>
+#include <dm.h>
+#include <pci.h>
+#include <asm/test.h>
+#include <p2sb.h>
+
+/**
+ * struct p2sb_emul_platdata - platform data for this device
+ *
+ * @command:	Current PCI command value
+ * @bar:	Current base address values
+ */
+struct p2sb_emul_platdata {
+	u16 command;
+	u32 bar[6];
+};
+
+enum {
+	/* This emulator supports 16 different devices */
+	MEMMAP_SIZE	= 16 << PCR_PORTID_SHIFT,
+};
+
+static struct pci_bar {
+	int type;
+	u32 size;
+} barinfo[] = {
+	{ PCI_BASE_ADDRESS_MEM_TYPE_32, MEMMAP_SIZE },
+	{ 0, 0 },
+	{ 0, 0 },
+	{ 0, 0 },
+	{ 0, 0 },
+	{ 0, 0 },
+};
+
+struct p2sb_emul_priv {
+	u8 regs[16];
+};
+
+static int sandbox_p2sb_emul_read_config(struct udevice *emul, uint offset,
+					 ulong *valuep, enum pci_size_t size)
+{
+	struct p2sb_emul_platdata *plat = dev_get_platdata(emul);
+
+	switch (offset) {
+	case PCI_COMMAND:
+		*valuep = plat->command;
+		break;
+	case PCI_HEADER_TYPE:
+		*valuep = PCI_HEADER_TYPE_NORMAL;
+		break;
+	case PCI_VENDOR_ID:
+		*valuep = SANDBOX_PCI_VENDOR_ID;
+		break;
+	case PCI_DEVICE_ID:
+		*valuep = SANDBOX_PCI_P2SB_EMUL_ID;
+		break;
+	case PCI_CLASS_DEVICE:
+		if (size == PCI_SIZE_8) {
+			*valuep = SANDBOX_PCI_CLASS_SUB_CODE;
+		} else {
+			*valuep = (SANDBOX_PCI_CLASS_CODE << 8) |
+					SANDBOX_PCI_CLASS_SUB_CODE;
+		}
+		break;
+	case PCI_CLASS_CODE:
+		*valuep = SANDBOX_PCI_CLASS_CODE;
+		break;
+	case PCI_BASE_ADDRESS_0:
+	case PCI_BASE_ADDRESS_1:
+	case PCI_BASE_ADDRESS_2:
+	case PCI_BASE_ADDRESS_3:
+	case PCI_BASE_ADDRESS_4:
+	case PCI_BASE_ADDRESS_5: {
+		int barnum;
+		u32 *bar;
+
+		barnum = pci_offset_to_barnum(offset);
+		bar = &plat->bar[barnum];
+
+		*valuep = sandbox_pci_read_bar(*bar, barinfo[barnum].type,
+					       barinfo[barnum].size);
+		break;
+	}
+	case PCI_CAPABILITY_LIST:
+		*valuep = PCI_CAP_ID_PM_OFFSET;
+		break;
+	}
+
+	return 0;
+}
+
+static int sandbox_p2sb_emul_write_config(struct udevice *emul, uint offset,
+					  ulong value, enum pci_size_t size)
+{
+	struct p2sb_emul_platdata *plat = dev_get_platdata(emul);
+
+	switch (offset) {
+	case PCI_COMMAND:
+		plat->command = value;
+		break;
+	case PCI_BASE_ADDRESS_0:
+	case PCI_BASE_ADDRESS_1: {
+		int barnum;
+		u32 *bar;
+
+		barnum = pci_offset_to_barnum(offset);
+		bar = &plat->bar[barnum];
+
+		log_debug("w bar %d=%lx\n", barnum, value);
+		*bar = value;
+		/* space indicator (bit#0) is read-only */
+		*bar |= barinfo[barnum].type;
+		break;
+	}
+	}
+
+	return 0;
+}
+
+static int sandbox_p2sb_emul_find_bar(struct udevice *emul, unsigned int addr,
+				      int *barnump, unsigned int *offsetp)
+{
+	struct p2sb_emul_platdata *plat = dev_get_platdata(emul);
+	int barnum;
+
+	for (barnum = 0; barnum < ARRAY_SIZE(barinfo); barnum++) {
+		unsigned int size = barinfo[barnum].size;
+		u32 base = plat->bar[barnum] & ~PCI_BASE_ADDRESS_SPACE;
+
+		if (addr >= base && addr < base + size) {
+			*barnump = barnum;
+			*offsetp = addr - base;
+			return 0;
+		}
+	}
+	*barnump = -1;
+
+	return -ENOENT;
+}
+
+static int sandbox_p2sb_emul_read_io(struct udevice *dev, unsigned int addr,
+				     ulong *valuep, enum pci_size_t size)
+{
+	unsigned int offset;
+	int barnum;
+	int ret;
+
+	ret = sandbox_p2sb_emul_find_bar(dev, addr, &barnum, &offset);
+	if (ret)
+		return ret;
+
+	if (barnum == 4)
+		*valuep = offset;
+	else if (barnum == 0)
+		*valuep = offset;
+
+	return 0;
+}
+
+static int sandbox_p2sb_emul_write_io(struct udevice *dev, unsigned int addr,
+				      ulong value, enum pci_size_t size)
+{
+	unsigned int offset;
+	int barnum;
+	int ret;
+
+	ret = sandbox_p2sb_emul_find_bar(dev, addr, &barnum, &offset);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int find_p2sb_channel(struct udevice *emul, uint offset,
+			     struct udevice **devp)
+{
+	uint pid = offset >> PCR_PORTID_SHIFT;
+	struct udevice *p2sb, *dev;
+	int ret;
+
+	ret = sandbox_pci_get_client(emul, &p2sb);
+	if (ret)
+		return log_msg_ret("No client", ret);
+
+	device_foreach_child(dev, p2sb) {
+		struct p2sb_child_platdata *pplat =
+			 dev_get_parent_platdata(dev);
+
+		log_debug("   - child %s, pid %d, want %d\n", dev->name,
+			  pplat->pid, pid);
+		if (pid == pplat->pid) {
+			*devp = dev;
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+static int sandbox_p2sb_emul_map_physmem(struct udevice *dev,
+					 phys_addr_t addr, unsigned long *lenp,
+					 void **ptrp)
+{
+	struct p2sb_emul_priv *priv = dev_get_priv(dev);
+	struct udevice *child;
+	unsigned int offset;
+	int barnum;
+	int ret;
+
+	log_debug("map %x: ", (uint)addr);
+	ret = sandbox_p2sb_emul_find_bar(dev, addr, &barnum, &offset);
+	if (ret)
+		return log_msg_ret("Cannot find bar", ret);
+	log_debug("bar %d, offset %x\n", barnum, offset);
+
+	if (barnum != 0)
+		return log_msg_ret("Unknown BAR", -EINVAL);
+
+	ret = find_p2sb_channel(dev, offset, &child);
+	if (ret)
+		return log_msg_ret("Cannot find channel", ret);
+
+	offset &= ((1 << PCR_PORTID_SHIFT) - 1);
+	ret = axi_read(child, offset, priv->regs, AXI_SIZE_32);
+	if (ret)
+		return log_msg_ret("Child read failed", ret);
+	*ptrp = priv->regs + (offset & 3);
+	*lenp = 4;
+
+	return 0;
+}
+
+static struct dm_pci_emul_ops sandbox_p2sb_emul_emul_ops = {
+	.read_config = sandbox_p2sb_emul_read_config,
+	.write_config = sandbox_p2sb_emul_write_config,
+	.read_io = sandbox_p2sb_emul_read_io,
+	.write_io = sandbox_p2sb_emul_write_io,
+	.map_physmem = sandbox_p2sb_emul_map_physmem,
+};
+
+static const struct udevice_id sandbox_p2sb_emul_ids[] = {
+	{ .compatible = "sandbox,p2sb-emul" },
+	{ }
+};
+
+U_BOOT_DRIVER(sandbox_p2sb_emul_emul) = {
+	.name		= "sandbox_p2sb_emul_emul",
+	.id		= UCLASS_PCI_EMUL,
+	.of_match	= sandbox_p2sb_emul_ids,
+	.ops		= &sandbox_p2sb_emul_emul_ops,
+	.priv_auto_alloc_size = sizeof(struct p2sb_emul_priv),
+	.platdata_auto_alloc_size = sizeof(struct p2sb_emul_platdata),
+};
+
+static struct pci_device_id sandbox_p2sb_emul_supported[] = {
+	{ PCI_VDEVICE(SANDBOX, SANDBOX_PCI_PMC_EMUL_ID) },
+	{},
+};
+
+U_BOOT_PCI_DEVICE(sandbox_p2sb_emul_emul, sandbox_p2sb_emul_supported);