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>

1 files changed, 171 insertions, 0 deletions

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;
+}