dm: sandbox: pci: Add PCI support for sandbox

Add the required header information, device tree nodes and I/O accessor
functions to support PCI on sandbox. All devices are emulated by drivers
which can be added as required for testing or development.
Signed-off-by: Simon Glass <sjg@chromium.org>

arch/sandbox/Kconfig

@@ -34,4 +34,11 @@ config DM_I2C
 config DM_TEST
 	default y
 
+config PCI
+	bool "PCI support"
+	help
+	  Enable support for PCI (Peripheral Interconnect Bus), a type of bus
+	  used on some devices to allow the CPU to communicate with its
+	  peripherals.
+
 endmenu

arch/sandbox/cpu/cpu.c

@@ -2,7 +2,7 @@
  * Copyright (c) 2011 The Chromium OS Authors.
  * SPDX-License-Identifier:	GPL-2.0+
  */
-
+#define DEBUG
 #include <common.h>
 #include <dm/root.h>
 #include <os.h>
@@ -10,6 +10,15 @@
 
 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
+
 void reset_cpu(ulong ignored)
 {
 	if (state_uninit())
@@ -59,9 +68,39 @@ int cleanup_before_linux(void)
 
 void *map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
 {
+#ifdef CONFIG_PCI
+	unsigned long plen = len;
+	void *ptr;
+
+	map_dev = NULL;
+	if (enable_pci_map && !pci_map_physmem(paddr, &len, &map_dev, &ptr)) {
+		if (plen != len) {
+			printf("%s: Warning: partial map at %x, wanted %lx, got %lx\n",
+			       __func__, paddr, len, plen);
+		}
+		map_len = len;
+		return ptr;
+	}
+#endif
+
 	return (void *)(gd->arch.ram_buf + paddr);
 }
 
+void unmap_physmem(const void *vaddr, unsigned long flags)
+{
+#ifdef CONFIG_PCI
+	if (map_dev) {
+		pci_unmap_physmem(vaddr, map_len, map_dev);
+		map_dev = NULL;
+	}
+#endif
+}
+
+void sandbox_set_enable_pci_map(int enable)
+{
+	enable_pci_map = enable;
+}
+
 phys_addr_t map_to_sysmem(const void *ptr)
 {
 	return (u8 *)ptr - gd->arch.ram_buf;

arch/sandbox/dts/sandbox.dts

@@ -4,6 +4,10 @@
 	#address-cells = <1>;
 	#size-cells = <1>;
 
+	aliases {
+		pci0 = &pci;
+	};
+
 	chosen {
 		stdout-path = "/serial";
 	};
@@ -181,4 +185,20 @@
 		};
 	};
 
+	pci: pci-controller {
+		compatible = "sandbox,pci";
+		device_type = "pci";
+		#address-cells = <3>;
+		#size-cells = <2>;
+		ranges = <0x02000000 0 0x10000000 0x10000000 0 0x2000
+				0x01000000 0 0x20000000 0x20000000 0 0x2000>;
+		pci@1f,0 {
+			compatible = "pci-generic";
+			reg = <0xf800 0 0 0 0>;
+			emul@1f,0 {
+				compatible = "sandbox,swap-case";
+			};
+		};
+	};
+
 };

arch/sandbox/include/asm/io.h

@@ -22,10 +22,7 @@ void *map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags);
 /*
  * Take down a mapping set up by map_physmem().
  */
-static inline void unmap_physmem(void *vaddr, unsigned long flags)
-{
-
-}
+void unmap_physmem(const void *vaddr, unsigned long flags);
 
 /* For sandbox, we want addresses to point into our RAM buffer */
 static inline void *map_sysmem(phys_addr_t paddr, unsigned long len)
@@ -33,8 +30,10 @@ static inline void *map_sysmem(phys_addr_t paddr, unsigned long len)
 	return map_physmem(paddr, len, MAP_WRBACK);
 }
 
+/* Remove a previous mapping */
 static inline void unmap_sysmem(const void *vaddr)
 {
+	unmap_physmem(vaddr, MAP_WRBACK);
 }
 
 /* Map from a pointer to our RAM buffer */
@@ -48,6 +47,15 @@ phys_addr_t map_to_sysmem(const void *ptr);
 #define writew(v, addr)
 #define writel(v, addr)
 
+/* I/O access functions */
+int inl(unsigned int addr);
+int inw(unsigned int addr);
+int inb(unsigned int addr);
+
+void outl(unsigned int value, unsigned int addr);
+void outw(unsigned int value, unsigned int addr);
+void outb(unsigned int value, unsigned int addr);
+
 #include <iotrace.h>
 
 #endif

arch/sandbox/include/asm/processor.h

+/*
+ * Copyright (c) 2014 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _ASM_PROCESSOR_H
+#define _ASM_PROCESSOR_H
+
+/* This file is required for PCI */
+
+#endif

arch/sandbox/include/asm/test.h

@@ -10,7 +10,12 @@
 #define __ASM_TEST_H
 
 /* The sandbox driver always permits an I2C device with this address */
-#define SANDBOX_I2C_TEST_ADDR	0x59
+#define SANDBOX_I2C_TEST_ADDR		0x59
+
+#define SANDBOX_PCI_VENDOR_ID		0x1234
+#define SANDBOX_PCI_DEVICE_ID		0x5678
+#define SANDBOX_PCI_CLASS_CODE		PCI_CLASS_CODE_COMM
+#define SANDBOX_PCI_CLASS_SUB_CODE	PCI_CLASS_SUB_CODE_COMM_SERIAL
 
 enum sandbox_i2c_eeprom_test_mode {
 	SIE_TEST_MODE_NONE,

arch/sandbox/include/asm/u-boot-sandbox.h

@@ -27,4 +27,52 @@ int cleanup_before_linux(void);
 /* drivers/video/sandbox_sdl.c */
 int sandbox_lcd_sdl_early_init(void);
 
+/**
+ * pci_map_physmem() - map a PCI device into memory
+ *
+ * This is used on sandbox to map a device into memory so that it can be
+ * used with normal memory access. After this call, some part of the device's
+ * internal structure becomes visible.
+ *
+ * This function is normally called from sandbox's map_sysmem() automatically.
+ *
+ * @paddr:	Physical memory address, normally corresponding to a PCI BAR
+ * @lenp:	On entry, the size of the area to map, On exit it is updated
+ *		to the size actually mapped, which may be less if the device
+ *		has less space
+ * @devp:	Returns the device which mapped into this space
+ * @ptrp:	Returns a pointer to the mapped address. The device's space
+ *		can be accessed as @lenp bytes starting here
+ * @return 0 if OK, -ve on error
+ */
+int pci_map_physmem(phys_addr_t paddr, unsigned long *lenp,
+		    struct udevice **devp, void **ptrp);
+
+/**
+ * pci_unmap_physmem() - undo a memory mapping
+ *
+ * This must be called after pci_map_physmem() to undo the mapping.
+ *
+ * @paddr:	Physical memory address, as passed to pci_map_physmem()
+ * @len:	Size of area mapped, as returned by pci_map_physmem()
+ * @dev:	Device to unmap, as returned by pci_map_physmem()
+ * @return 0 if OK, -ve on error
+ */
+int pci_unmap_physmem(const void *addr, unsigned long len,
+		      struct udevice *dev);
+
+/**
+ * sandbox_set_enable_pci_map() - Enable / disable PCI address mapping
+ *
+ * Since address mapping involves calling every driver, provide a way to
+ * enable and disable this. It can be handled automatically by the emulator
+ * uclass, which knows if any emulators are currently active.
+ *
+ * If this is disabled, pci_map_physmem() will not be called from
+ * map_sysmem().
+ *
+ * @enable: 0 to disable, 1 to enable
+ */
+void sandbox_set_enable_pci_map(int enable);
+
 #endif	/* _U_BOOT_SANDBOX_H_ */

arch/sandbox/lib/Makefile

@@ -7,5 +7,5 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-
 obj-y	+= interrupts.o
+obj-$(CONFIG_PCI)	+= pci_io.o

arch/sandbox/lib/pci_io.c

+/*
+ * Copyright (c) 2014 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+/*
+ * IO space access commands.
+ */
+
+#include <common.h>
+#include <command.h>
+#include <dm.h>
+#include <asm/io.h>
+
+int pci_map_physmem(phys_addr_t paddr, unsigned long *lenp,
+		    struct udevice **devp, void **ptrp)
+{
+	struct udevice *dev;
+	int ret;
+
+	*ptrp = 0;
+	for (uclass_first_device(UCLASS_PCI_EMUL, &dev);
+	     dev;
+	     uclass_next_device(&dev)) {
+		struct dm_pci_emul_ops *ops = pci_get_emul_ops(dev);
+
+		if (!ops || !ops->map_physmem)
+			continue;
+		ret = (ops->map_physmem)(dev, paddr, lenp, ptrp);
+		if (ret)
+			continue;
+		*devp = dev;
+		return 0;
+	}
+
+	debug("%s: failed: addr=%x\n", __func__, paddr);
+	return -ENOSYS;
+}
+
+int pci_unmap_physmem(const void *vaddr, unsigned long len,
+		      struct udevice *dev)
+{
+	struct dm_pci_emul_ops *ops = pci_get_emul_ops(dev);
+
+	if (!ops || !ops->unmap_physmem)
+		return -ENOSYS;
+	return (ops->unmap_physmem)(dev, vaddr, len);
+}
+
+static int pci_io_read(unsigned int addr, ulong *valuep, pci_size_t size)
+{
+	struct udevice *dev;
+	int ret;
+
+	*valuep = pci_get_ff(size);
+	for (uclass_first_device(UCLASS_PCI_EMUL, &dev);
+	     dev;
+	     uclass_next_device(&dev)) {
+		struct dm_pci_emul_ops *ops = pci_get_emul_ops(dev);
+
+		if (ops && ops->read_io) {
+			ret = (ops->read_io)(dev, addr, valuep, size);
+			if (!ret)
+				return 0;
+		}
+	}
+
+	debug("%s: failed: addr=%x\n", __func__, addr);
+	return -ENOSYS;
+}
+
+static int pci_io_write(unsigned int addr, ulong value, pci_size_t size)
+{
+	struct udevice *dev;
+	int ret;
+
+	for (uclass_first_device(UCLASS_PCI_EMUL, &dev);
+	     dev;
+	     uclass_next_device(&dev)) {
+		struct dm_pci_emul_ops *ops = pci_get_emul_ops(dev);
+
+		if (ops && ops->write_io) {
+			ret = (ops->write_io)(dev, addr, value, size);
+			if (!ret)
+				return 0;
+		}
+	}
+
+	debug("%s: failed: addr=%x, value=%lx\n", __func__, addr, value);
+	return -ENOSYS;
+}
+
+int inl(unsigned int addr)
+{
+	unsigned long value;
+	int ret;
+
+	ret = pci_io_read(addr, &value, PCI_SIZE_32);
+
+	return ret ? 0 : value;
+}
+
+int inw(unsigned int addr)
+{
+	unsigned long value;
+	int ret;
+
+	ret = pci_io_read(addr, &value, PCI_SIZE_16);
+
+	return ret ? 0 : value;
+}
+
+int inb(unsigned int addr)
+{
+	unsigned long value;
+	int ret;
+
+	ret = pci_io_read(addr, &value, PCI_SIZE_8);
+
+	return ret ? 0 : value;
+}
+
+void outl(unsigned int value, unsigned int addr)
+{
+	pci_io_write(addr, value, PCI_SIZE_32);
+}
+
+void outw(unsigned int value, unsigned int addr)
+{
+	pci_io_write(addr, value, PCI_SIZE_16);
+}
+
+void outb(unsigned int value, unsigned int addr)
+{
+	pci_io_write(addr, value, PCI_SIZE_8);
+}