soc/apollolake/lpc: Open I/O to LPC based on resource allocation

Besides a number of fixed memory windows, Apollolake supports
opening a configureable 64 KiB MMIO window, as well as four PMIO
windows to the LPC bus. Open up these windows dynamically, based on
how resources were allocated to the child LPC devices.

Change-Id: I170e861693cb6fd1be38889adc951f197a13460f
Signed-off-by: Alexandru Gagniuc <alexandrux.gagniuc@intel.com>
Reviewed-on: https://review.coreboot.org/14584
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

5 files changed, 313 insertions, 1 deletions

diff --git a/src/soc/intel/apollolake/Makefile.inc b/src/soc/intel/apollolake/Makefile.inc
index e162a01a13..6b934a891a 100644
--- a/src/soc/intel/apollolake/Makefile.inc
+++ b/src/soc/intel/apollolake/Makefile.inc
@@ -13,6 +13,7 @@ bootblock-y += bootblock/cache_as_ram.S
 bootblock-y += bootblock/bootblock.c
 bootblock-y += car.c
 bootblock-y += gpio.c
+bootblock-y += lpc_lib.c
 bootblock-y += mmap_boot.c
 bootblock-y += placeholders.c
 bootblock-y += tsc_freq.c
@@ -23,6 +24,7 @@ romstage-y += car.c
 romstage-$(CONFIG_PLATFORM_USES_FSP2_0) += romstage.c
 romstage-y += gpio.c
 romstage-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
+romstage-y += lpc_lib.c
 romstage-y += memmap.c
 romstage-y += mmap_boot.c
 romstage-y += tsc_freq.c
@@ -38,6 +40,7 @@ ramstage-y += placeholders.c
 ramstage-y += gpio.c
 ramstage-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
 ramstage-y += lpc.c
+ramstage-y += lpc_lib.c
 ramstage-y += memmap.c
 ramstage-y += mmap_boot.c
 ramstage-y += uart.c
diff --git a/src/soc/intel/apollolake/include/soc/lpc.h b/src/soc/intel/apollolake/include/soc/lpc.h
new file mode 100644
index 0000000000..9a1c397d8e
--- /dev/null
+++ b/src/soc/intel/apollolake/include/soc/lpc.h
@@ -0,0 +1,67 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 Intel Corp.
+ * (Written by Alexandru Gagniuc <alexandrux.gagniuc@intel.com> for Intel Corp.)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _SOC_APOLLOLAKE_LPC_H_
+#define _SOC_APOLLOLAKE_LPC_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define REG_SERIRQ_CTL			0x64
+#define  SCNT_EN			(1 << 7)
+#define  SCNT_MODE			(1 << 6)
+
+/*
+ * IO decode enable macros are in the format IO_<peripheral>_<IO port>.
+ * For example, to open ports 0x60, 0x64 for the keyboard controller,
+ * use IOE_KBC_60_64 macro. For IOE_ macros that do not specify a port range,
+ * the port range is selectable via the IO decodes register (not referenced).
+ */
+#define REG_IO_ENABLES			0x82
+#define  IOE_EC_4E_4F			(1 << 13)
+#define  IOE_SUPERIO_2E_2F		(1 << 12)
+#define  IOE_EC_62_66			(1 << 11)
+#define  IOE_KBC_60_64			(1 << 10)
+#define  IOE_HGE_208			(1 << 9)
+#define  IOE_LGE_200			(1 << 8)
+#define  IOE_FDD_EN			(1 << 3)
+#define  IOE_LPT_EN			(1 << 2)
+#define  IOE_COMB_EN			(1 << 1)
+#define  IOE_COMA_EN			(1 << 0)
+#define REG_GENERIC_IO_RANGE(n)		((((n) & 0x3) * 4) + 0x84)
+#define  LGIR_AMASK_MASK		(0xfc << 16)
+#define  LGIR_ADDR_MASK			0xfffc
+#define  LGIR_EN			(1 << 0)
+#define LGIR_MAX_WINDOW_SIZE		256
+#define NUM_GENERIC_IO_RANGES		4
+#define REG_GENERIC_MEM_RANGE		0x98
+#define  LGMR_ADDR_MASK			0xffff0000
+#define  LGMR_EN			(1 << 0)
+#define LGMR_WINDOW_SIZE		(64 * KiB)
+
+/* Enable fixed IO ranges to LPC. IOE_* macros can be OR'ed together. */
+void lpc_enable_fixed_io_ranges(uint16_t io_enables);
+/* Open a generic IO window to the LPC bus. Four windows are available. */
+void lpc_open_pmio_window(uint16_t base, uint16_t size);
+/* Close all generic IO windows to the LPC bus. */
+void lpc_close_pmio_windows(void);
+/* Open a generic MMIO window to the LPC bus. One window is available. */
+void lpc_open_mmio_window(uintptr_t base, size_t size);
+/* Returns true if given window is decoded to LPC via a fixed range. */
+bool lpc_fits_fixed_mmio_window(uintptr_t base, size_t size);
+
+#endif /* _SOC_APOLLOLAKE_LPC_H_ */
diff --git a/src/soc/intel/apollolake/include/soc/pci_devs.h b/src/soc/intel/apollolake/include/soc/pci_devs.h
index 7b8caafd69..ec550e8810 100644
--- a/src/soc/intel/apollolake/include/soc/pci_devs.h
+++ b/src/soc/intel/apollolake/include/soc/pci_devs.h
@@ -51,5 +51,6 @@
 #define P2SB_DEV		PCI_DEV(0, 0xd, 0)
 #define PMC_DEV			PCI_DEV(0, 0xd, 1)
 #define SPI_DEV			PCI_DEV(0, 0xd, 2)
+#define LPC_DEV			PCI_DEV(0, 0x1f, 0)
 
 #endif
diff --git a/src/soc/intel/apollolake/lpc.c b/src/soc/intel/apollolake/lpc.c
index 10677df503..5b552d8491 100644
--- a/src/soc/intel/apollolake/lpc.c
+++ b/src/soc/intel/apollolake/lpc.c
@@ -19,8 +19,27 @@
 #include <device/pci.h>
 #include <device/pci_ids.h>
 #include <soc/acpi.h>
+#include <soc/lpc.h>
 #include <soc/pci_ids.h>
 
+/*
+ * SCOPE:
+ * The purpose of this driver is to eliminate manual resource allocation for
+ * devices under the LPC bridge.
+ *
+ * BACKGROUND:
+ * The resource allocator reserves IO and memory resources to devices on the
+ * LPC bus, but it is up to the hardware driver to make sure that those
+ * resources are decoded to the LPC bus. This is what this driver does.
+ *
+ * THEORY OF OPERATION:
+ * The .scan_bus member of the driver's ops will scan the static device tree
+ * (devicetree.cb) and invoke drivers of devices on the LPC bus. This creates
+ * a list of child devices, along with their resources. set_child_resources()
+ * parses that list and looks for resources needed by the child devices. It
+ * opens up IO and memory windows as needed.
+ */
+
 static void soc_lpc_add_io_resources(device_t dev)
 {
 	struct resource *res;
@@ -41,12 +60,63 @@ static void soc_lpc_read_resources(device_t dev)
 	soc_lpc_add_io_resources(dev);
 }
 
+static void set_child_resources(struct device *dev);
+
+static void loop_resources(struct device *dev)
+{
+	struct resource *res;
+
+	for (res = dev->resource_list; res; res = res->next) {
+
+		if (res->flags & IORESOURCE_IO) {
+			lpc_open_pmio_window(res->base, res->size);
+		}
+
+		if (res->flags & IORESOURCE_MEM) {
+			/* Check if this is already decoded. */
+			if (lpc_fits_fixed_mmio_window(res->base, res->size))
+				continue;
+
+			lpc_open_mmio_window(res->base, res->size);
+		}
+
+	}
+	set_child_resources(dev);
+}
+
+/*
+ * Loop through all the child devices' resources, and open up windows to the
+ * LPC bus, as appropriate.
+ */
+static void set_child_resources(struct device *dev)
+{
+	struct bus *link;
+	struct device *child;
+
+	for (link = dev->link_list; link; link = link->next) {
+		for (child = link->children; child; child = child->sibling) {
+			loop_resources(child);
+		}
+	}
+}
+
+static void set_resources(device_t dev)
+{
+	pci_dev_set_resources(dev);
+
+	/* Close all previously opened windows and allocate from scratch. */
+	lpc_close_pmio_windows();
+	/* Now open up windows to devices which have declared resources. */
+	set_child_resources(dev);
+}
+
 static struct device_operations device_ops = {
 	.read_resources = &soc_lpc_read_resources,
-	.set_resources = &pci_dev_set_resources,
+	.set_resources = set_resources,
 	.enable_resources = &pci_dev_enable_resources,
 	.write_acpi_tables = southbridge_write_acpi_tables,
 	.acpi_inject_dsdt_generator = southbridge_inject_dsdt,
+	.scan_bus = scan_lpc_bus,
 };
 
 static const struct pci_driver soc_lpc __pci_driver = {
diff --git a/src/soc/intel/apollolake/lpc_lib.c b/src/soc/intel/apollolake/lpc_lib.c
new file mode 100644
index 0000000000..14e052eace
--- /dev/null
+++ b/src/soc/intel/apollolake/lpc_lib.c
@@ -0,0 +1,171 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 Intel Corp.
+ * (Written by Alexandru Gagniuc <alexandrux.gagniuc@intel.com> for Intel Corp.)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define __SIMPLE_DEVICE__
+
+#include <console/console.h>
+#include <device/pci.h>
+#include <lib.h>
+#include <soc/lpc.h>
+#include <soc/pci_devs.h>
+
+/*
+ * These are MMIO ranges that the silicon designers decided are always going to
+ * be decoded to LPC.
+ */
+static const struct lpc_mmio_range {
+	uintptr_t base;
+	size_t size;
+} lpc_fixed_mmio_ranges[] = {
+	{ 0xfed40000, 0x8000 },
+	{ 0xfedc0000, 0x4000 },
+	{ 0xfed20800, 16 },
+	{ 0xfed20880, 8 },
+	{ 0xfed208e0, 16 },
+	{ 0xfed208f0, 8 },
+	{ 0xfed30800, 16 },
+	{ 0xfed30880, 8 },
+	{ 0xfed308e0, 16 },
+	{ 0xfed308f0, 8 },
+	{ 0, 0 }
+};
+
+void lpc_enable_fixed_io_ranges(uint16_t io_enables)
+{
+	uint16_t reg_io_enables;
+
+	reg_io_enables = pci_read_config16(LPC_DEV, REG_IO_ENABLES);
+	io_enables |= reg_io_enables;
+	pci_write_config16(LPC_DEV, REG_IO_ENABLES, io_enables);
+}
+
+/*
+ * Find the first unused IO window.
+ * Returns -1 if not found, 0 for reg 0x84, 1 for reg 0x88 ...
+ */
+static int find_unused_pmio_window(void)
+{
+	int i;
+	uint32_t lgir;
+
+	for (i = 0; i < NUM_GENERIC_IO_RANGES; i++) {
+		lgir = pci_read_config32(LPC_DEV, REG_GENERIC_IO_RANGE(i));
+
+		if (!(lgir & LGIR_EN))
+			return i;
+	}
+
+	return -1;
+}
+
+void lpc_close_pmio_windows(void)
+{
+	size_t i;
+
+	for (i = 0; i < NUM_GENERIC_IO_RANGES; i++)
+		pci_write_config32(LPC_DEV, REG_GENERIC_IO_RANGE(i), 0);
+}
+
+void lpc_open_pmio_window(uint16_t base, uint16_t size)
+{
+	int lgir_reg_num;
+	uint32_t lgir_reg_offset, lgir, window_size, alignment;
+	resource_t bridged_size, bridge_base;
+
+	printk(BIOS_SPEW, "LPC: Trying to open IO window from %x size %x\n",
+				base, size);
+
+	bridged_size = 0;
+	bridge_base = base;
+
+	while (bridged_size < size) {
+		lgir_reg_num = find_unused_pmio_window();
+		if (lgir_reg_num < 0) {
+			printk(BIOS_ERR,
+				"LPC: Cannot open IO window: %llx size %llx\n",
+				bridge_base, size - bridged_size);
+			printk(BIOS_ERR, "No more IO windows\n");
+			return;
+		}
+		lgir_reg_offset = REG_GENERIC_IO_RANGE(lgir_reg_num);
+
+		/* Each IO range register can only open a 256-byte window. */
+		window_size = MIN(size, LGIR_MAX_WINDOW_SIZE);
+
+		/* Window size must be a power of two for the AMASK to work. */
+		alignment = 1 << (log2_ceil(window_size));
+		window_size = ALIGN_UP(window_size, alignment);
+
+		/* Address[15:2] in LGIR[15:12] and Mask[7:2] in LGIR[23:18]. */
+		lgir = (bridge_base & LGIR_ADDR_MASK) | LGIR_EN;
+		lgir |= ((window_size - 1) << 16) & LGIR_AMASK_MASK;
+
+		pci_write_config32(LPC_DEV, lgir_reg_offset, lgir);
+
+		printk(BIOS_DEBUG,
+		       "LPC: Opened IO window LGIR%d: base %llx size %x\n",
+		       lgir_reg_num, bridge_base, window_size);
+
+		bridged_size += window_size;
+		bridge_base += window_size;
+	}
+}
+
+void lpc_open_mmio_window(uintptr_t base, size_t size)
+{
+	uint32_t lgmr;
+
+	lgmr = pci_read_config32(LPC_DEV, REG_GENERIC_MEM_RANGE);
+
+	if (lgmr & LGMR_EN) {
+		printk(BIOS_ERR,
+		       "LPC: Cannot open window to resource %lx size %lx\n",
+		       base, size);
+		printk(BIOS_ERR, "LPC: MMIO window already in use\n");
+		return;
+	}
+
+	if (size > LGMR_WINDOW_SIZE) {
+		printk(BIOS_WARNING,
+		       "LPC:  Resource %lx size %lx larger than window(%x)\n",
+		       base, size, LGMR_WINDOW_SIZE);
+	}
+
+	lgmr = (base & LGMR_ADDR_MASK) | LGMR_EN;
+
+	pci_write_config32(LPC_DEV, REG_GENERIC_MEM_RANGE, lgmr);
+}
+
+bool lpc_fits_fixed_mmio_window(uintptr_t base, size_t size)
+{
+	resource_t res_end, range_end;
+	const struct lpc_mmio_range *range;
+
+	for (range = lpc_fixed_mmio_ranges; range->size; range++) {
+		range_end = range->base + range->size;
+		res_end = base + size;
+
+		if ((base >= range->base) && (res_end <= range_end)) {
+			printk(BIOS_DEBUG,
+			       "Resource %lx size %lx fits in fixed window"
+			       " %lx size %lx\n",
+			       base, size, range->base, range->size);
+			return true;
+		}
+	}
+	return false;
+}