pci: Add support for p2sb uclass

The Primary-to-Sideband bus (P2SB) is used to access various peripherals
through memory-mapped I/O in a large chunk of PCI space. The space is
segmented into different channels and peripherals are accessed by
device-specific means within those channels. Devices should be added in
the device tree as subnodes of the p2sb.

This adds a uclass and enables it for sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

drivers/misc/Kconfig

@@ -226,6 +226,39 @@ config NUVOTON_NCT6102D
 	  disable the legacy UART, the watchdog or other devices
 	  in the Nuvoton Super IO chips on X86 platforms.
 
+config P2SB
+	bool "Intel Primary-to-Sideband Bus"
+	depends on X86 || SANDBOX
+	help
+	  This enables support for the Intel Primary-to-Sideband bus,
+	  abbreviated to P2SB. The P2SB is used to access various peripherals
+	  such as eSPI, GPIO, through memory-mapped I/O in a large chunk of PCI
+	  space. The space is segmented into different channels and peripherals
+	  are accessed by device-specific means within those channels. Devices
+	  should be added in the device tree as subnodes of the P2SB. A
+	  Peripheral Channel Register? (PCR) API is provided to access those
+	  devices - see pcr_readl(), etc.
+
+config SPL_P2SB
+	bool "Intel Primary-to-Sideband Bus in SPL"
+	depends on SPL && (X86 || SANDBOX)
+	help
+	  The Primary-to-Sideband bus is used to access various peripherals
+	  through memory-mapped I/O in a large chunk of PCI space. The space is
+	  segmented into different channels and peripherals are accessed by
+	  device-specific means within those channels. Devices should be added
+	  in the device tree as subnodes of the p2sb.
+
+config TPL_P2SB
+	bool "Intel Primary-to-Sideband Bus in TPL"
+	depends on TPL && (X86 || SANDBOX)
+	help
+	  The Primary-to-Sideband bus is used to access various peripherals
+	  through memory-mapped I/O in a large chunk of PCI space. The space is
+	  segmented into different channels and peripherals are accessed by
+	  device-specific means within those channels. Devices should be added
+	  in the device tree as subnodes of the p2sb.
+
 config PWRSEQ
 	bool "Enable power-sequencing drivers"
 	depends on DM

drivers/misc/Makefile

@@ -49,6 +49,7 @@ obj-$(CONFIG_MXC_OCOTP) += mxc_ocotp.o
 obj-$(CONFIG_MXS_OCOTP) += mxs_ocotp.o
 obj-$(CONFIG_NS87308) += ns87308.o
 obj-$(CONFIG_NUVOTON_NCT6102D) += nuvoton_nct6102d.o
+obj-$(CONFIG_P2SB) += p2sb-uclass.o
 obj-$(CONFIG_PCA9551_LED) += pca9551_led.o
 obj-$(CONFIG_$(SPL_)PWRSEQ) += pwrseq-uclass.o
 obj-$(CONFIG_QFW) += qfw.o

drivers/misc/p2sb-uclass.c

@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Uclass for Primary-to-sideband bus, used to access various peripherals
+ *
+ * Copyright 2019 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <mapmem.h>
+#include <p2sb.h>
+#include <spl.h>
+#include <asm/io.h>
+#include <dm/uclass-internal.h>
+
+#define PCR_COMMON_IOSF_1_0	1
+
+static void *_pcr_reg_address(struct udevice *dev, uint offset)
+{
+	struct p2sb_child_platdata *pplat = dev_get_parent_platdata(dev);
+	struct udevice *p2sb = dev_get_parent(dev);
+	struct p2sb_uc_priv *upriv = dev_get_uclass_priv(p2sb);
+	uintptr_t reg_addr;
+
+	/* Create an address based off of port id and offset */
+	reg_addr = upriv->mmio_base;
+	reg_addr += pplat->pid << PCR_PORTID_SHIFT;
+	reg_addr += offset;
+
+	return map_sysmem(reg_addr, 4);
+}
+
+/*
+ * The mapping of addresses via the SBREG_BAR assumes the IOSF-SB
+ * agents are using 32-bit aligned accesses for their configuration
+ * registers. For IOSF versions greater than 1_0, IOSF-SB
+ * agents can use any access (8/16/32 bit aligned) for their
+ * configuration registers
+ */
+static inline void check_pcr_offset_align(uint offset, uint size)
+{
+	const size_t align = PCR_COMMON_IOSF_1_0 ? sizeof(uint32_t) : size;
+
+	assert(IS_ALIGNED(offset, align));
+}
+
+uint pcr_read32(struct udevice *dev, uint offset)
+{
+	void *ptr;
+	uint val;
+
+	/* Ensure the PCR offset is correctly aligned */
+	assert(IS_ALIGNED(offset, sizeof(uint32_t)));
+
+	ptr = _pcr_reg_address(dev, offset);
+	val = readl(ptr);
+	unmap_sysmem(ptr);
+
+	return val;
+}
+
+uint pcr_read16(struct udevice *dev, uint offset)
+{
+	/* Ensure the PCR offset is correctly aligned */
+	check_pcr_offset_align(offset, sizeof(uint16_t));
+
+	return readw(_pcr_reg_address(dev, offset));
+}
+
+uint pcr_read8(struct udevice *dev, uint offset)
+{
+	/* Ensure the PCR offset is correctly aligned */
+	check_pcr_offset_align(offset, sizeof(uint8_t));
+
+	return readb(_pcr_reg_address(dev, offset));
+}
+
+/*
+ * After every write one needs to perform a read an innocuous register to
+ * ensure the writes are completed for certain ports. This is done for
+ * all ports so that the callers don't need the per-port knowledge for
+ * each transaction.
+ */
+static void write_completion(struct udevice *dev, uint offset)
+{
+	readl(_pcr_reg_address(dev, ALIGN_DOWN(offset, sizeof(uint32_t))));
+}
+
+void pcr_write32(struct udevice *dev, uint offset, uint indata)
+{
+	/* Ensure the PCR offset is correctly aligned */
+	assert(IS_ALIGNED(offset, sizeof(indata)));
+
+	writel(indata, _pcr_reg_address(dev, offset));
+	/* Ensure the writes complete */
+	write_completion(dev, offset);
+}
+
+void pcr_write16(struct udevice *dev, uint offset, uint indata)
+{
+	/* Ensure the PCR offset is correctly aligned */
+	check_pcr_offset_align(offset, sizeof(uint16_t));
+
+	writew(indata, _pcr_reg_address(dev, offset));
+	/* Ensure the writes complete */
+	write_completion(dev, offset);
+}
+
+void pcr_write8(struct udevice *dev, uint offset, uint indata)
+{
+	/* Ensure the PCR offset is correctly aligned */
+	check_pcr_offset_align(offset, sizeof(uint8_t));
+
+	writeb(indata, _pcr_reg_address(dev, offset));
+	/* Ensure the writes complete */
+	write_completion(dev, offset);
+}
+
+void pcr_clrsetbits32(struct udevice *dev, uint offset, uint clr, uint set)
+{
+	uint data32;
+
+	data32 = pcr_read32(dev, offset);
+	data32 &= ~clr;
+	data32 |= set;
+	pcr_write32(dev, offset, data32);
+}
+
+void pcr_clrsetbits16(struct udevice *dev, uint offset, uint clr, uint set)
+{
+	uint data16;
+
+	data16 = pcr_read16(dev, offset);
+	data16 &= ~clr;
+	data16 |= set;
+	pcr_write16(dev, offset, data16);
+}
+
+void pcr_clrsetbits8(struct udevice *dev, uint offset, uint clr, uint set)
+{
+	uint data8;
+
+	data8 = pcr_read8(dev, offset);
+	data8 &= ~clr;
+	data8 |= set;
+	pcr_write8(dev, offset, data8);
+}
+
+int p2sb_get_port_id(struct udevice *dev)
+{
+	struct p2sb_child_platdata *pplat = dev_get_parent_platdata(dev);
+
+	return pplat->pid;
+}
+
+int p2sb_set_port_id(struct udevice *dev, int portid)
+{
+	struct udevice *ps2b;
+	struct p2sb_child_platdata *pplat;
+
+	if (!CONFIG_IS_ENABLED(OF_PLATDATA))
+		return -ENOSYS;
+
+	uclass_find_first_device(UCLASS_P2SB, &ps2b);
+	if (!ps2b)
+		return -EDEADLK;
+	dev->parent = ps2b;
+
+	/*
+	 * We must allocate this, since when the device was bound it did not
+	 * have a parent.
+	 * TODO(sjg@chromium.org): Add a parent pointer to child devices in dtoc
+	 */
+	dev->parent_platdata = malloc(sizeof(*pplat));
+	if (!dev->parent_platdata)
+		return -ENOMEM;
+	pplat = dev_get_parent_platdata(dev);
+	pplat->pid = portid;
+
+	return 0;
+}
+
+static int p2sb_child_post_bind(struct udevice *dev)
+{
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+	struct p2sb_child_platdata *pplat = dev_get_parent_platdata(dev);
+	int ret;
+	u32 pid;
+
+	ret = dev_read_u32(dev, "intel,p2sb-port-id", &pid);
+	if (ret)
+		return ret;
+	pplat->pid = pid;
+#endif
+
+	return 0;
+}
+
+static int p2sb_post_bind(struct udevice *dev)
+{
+	if (spl_phase() > PHASE_TPL && !CONFIG_IS_ENABLED(OF_PLATDATA))
+		return dm_scan_fdt_dev(dev);
+
+	return 0;
+}
+
+UCLASS_DRIVER(p2sb) = {
+	.id		= UCLASS_P2SB,
+	.name		= "p2sb",
+	.per_device_auto_alloc_size = sizeof(struct p2sb_uc_priv),
+	.post_bind	= p2sb_post_bind,
+	.child_post_bind = p2sb_child_post_bind,
+	.per_child_platdata_auto_alloc_size =
+		sizeof(struct p2sb_child_platdata),
+};

include/dm/uclass-id.h

@@ -70,6 +70,7 @@ enum uclass_id {
 	UCLASS_NOP,		/* No-op devices */
 	UCLASS_NORTHBRIDGE,	/* Intel Northbridge / SDRAM controller */
 	UCLASS_NVME,		/* NVM Express device */
+	UCLASS_P2SB,		/* (x86) Primary-to-Sideband Bus */
 	UCLASS_PANEL,		/* Display panel, such as an LCD */
 	UCLASS_PANEL_BACKLIGHT,	/* Backlight controller for panel */
 	UCLASS_PCH,		/* x86 platform controller hub */

include/p2sb.h

@@ -0,0 +1,135 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2019 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __p2sb_h
+#define __p2sb_h
+
+/* Port Id lives in bits 23:16 and register offset lives in 15:0 of address */
+#define PCR_PORTID_SHIFT	16
+
+/**
+ * struct p2sb_child_platdata - Information about each child of a p2sb device
+ *
+ * @pid: Port ID for this child
+ */
+struct p2sb_child_platdata {
+	uint pid;
+};
+
+/**
+ * struct p2sb_uc_priv - information for the uclass about each device
+ *
+ * This must be set up by the driver when it is probed
+ *
+ * @mmio_base: Base address of P2SB region
+ */
+struct p2sb_uc_priv {
+	uint mmio_base;
+};
+
+/**
+ * struct p2sb_ops - Operations for the P2SB (none at present)
+ */
+struct p2sb_ops {
+};
+
+#define p2sb_get_ops(dev)        ((struct p2sb_ops *)(dev)->driver->ops)
+
+/**
+ * pcr_read32/16/8() - Read from a PCR device
+ *
+ * Reads data from a PCR device within the P2SB
+ *
+ * @dev: Device to read from
+ * @offset: Offset within device to read
+ * @return value read
+ */
+uint pcr_read32(struct udevice *dev, uint offset);
+uint pcr_read16(struct udevice *dev, uint offset);
+uint pcr_read8(struct udevice *dev, uint offset);
+
+/**
+ * pcr_read32/16/8() - Write to a PCR device
+ *
+ * Writes data to a PCR device within the P2SB
+ *
+ * @dev: Device to write to
+ * @offset: Offset within device to write
+ * @data: Data to write
+ */
+void pcr_write32(struct udevice *dev, uint offset, uint data);
+void pcr_write16(struct udevice *dev, uint offset, uint data);
+void pcr_write8(struct udevice *dev, uint offset, uint data);
+
+/**
+ * pcr_clrsetbits32/16/8() - Update a PCR device
+ *
+ * Updates dat in a PCR device within the P2SB
+ *
+ * This reads from the device, clears and set bits, then writes back.
+ *
+ * new_data = (old_data & ~clr) | set
+ *
+ * @dev: Device to update
+ * @offset: Offset within device to update
+ * @clr: Bits to clear after reading
+ * @set: Bits to set before writing
+ */
+void pcr_clrsetbits32(struct udevice *dev, uint offset, uint clr, uint set);
+void pcr_clrsetbits16(struct udevice *dev, uint offset, uint clr, uint set);
+void pcr_clrsetbits8(struct udevice *dev, uint offset, uint clr, uint set);
+
+static inline void pcr_setbits32(struct udevice *dev, uint offset, uint set)
+{
+	return pcr_clrsetbits32(dev, offset, 0, set);
+}
+
+static inline void pcr_setbits16(struct udevice *dev, uint offset, uint set)
+{
+	return pcr_clrsetbits16(dev, offset, 0, set);
+}
+
+static inline void pcr_setbits8(struct udevice *dev, uint offset, uint set)
+{
+	return pcr_clrsetbits8(dev, offset, 0, set);
+}
+
+static inline void pcr_clrbits32(struct udevice *dev, uint offset, uint clr)
+{
+	return pcr_clrsetbits32(dev, offset, clr, 0);
+}
+
+static inline void pcr_clrbits16(struct udevice *dev, uint offset, uint clr)
+{
+	return pcr_clrsetbits16(dev, offset, clr, 0);
+}
+
+static inline void pcr_clrbits8(struct udevice *dev, uint offset, uint clr)
+{
+	return pcr_clrsetbits8(dev, offset, clr, 0);
+}
+
+/**
+ * p2sb_set_port_id() - Set the port ID for a p2sb child device
+ *
+ * This must be called in a device's bind() method when OF_PLATDATA is used
+ * since the uclass cannot access the device's of-platdata.
+ *
+ * @dev: Child device (whose parent is UCLASS_P2SB)
+ * @portid: Port ID of child device
+ * @return 0 if OK, -ENODEV is the p2sb device could not be found
+ */
+int p2sb_set_port_id(struct udevice *dev, int portid);
+
+/**
+ * p2sb_get_port_id() - Get the port ID for a p2sb child device
+ *
+ * @dev: Child device (whose parent is UCLASS_P2SB)
+ * @return Port ID of that child
+ */
+int p2sb_get_port_id(struct udevice *dev);
+
+#endif