lynxpoint: lpc resource reservations

This commit updates the Lynx Point resource reservations before
the coreboot allocator assigns resources. There is no need to mark
anything as subtractive decode because there are no devices/buses
linked to the LPC device.

The I/O range reservations consists of claiming the first 4KiB
of I/O space. The PMBASE, GPIOBASE, and LPC generic I/O decode
ranges are checked against the default claimed range. If those
ranges overlap or fall outside of the default range then those
resources are added.

The MMIO range reservations consist of claiming everything from
the I/O APIC to 4GiB. The RCBA and the LPC Generic Memory range
register are then conditionally added if they fall outside of
the default MMIO range.

Change-Id: I0f560a03814a2b15961fdbe61e4164cd54cff7a5
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2682
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

2 files changed, 113 insertions, 55 deletions

diff --git a/src/southbridge/intel/lynxpoint/lpc.c b/src/southbridge/intel/lynxpoint/lpc.c
index a44d80f802..facea7cdd6 100644
--- a/src/southbridge/intel/lynxpoint/lpc.c
+++ b/src/southbridge/intel/lynxpoint/lpc.c
@@ -574,74 +574,131 @@ static void lpc_init(struct device *dev)
 	pch_fixups(dev);
 }
 
-static void pch_lpc_read_resources(device_t dev)
+static void pch_lpc_add_mmio_resources(device_t dev)
 {
+	u32 reg;
 	struct resource *res;
-	config_t *config = dev->chip_info;
-	u8 io_index = 0;
-
-	/* Get the normal PCI resources of this device. */
-	pci_dev_read_resources(dev);
-
-	/* Add an extra subtractive resource for both memory and I/O. */
-	res = new_resource(dev, IOINDEX_SUBTRACTIVE(io_index++, 0));
-	res->base = 0;
-	res->size = 0x1000;
-	res->flags = IORESOURCE_IO | IORESOURCE_SUBTRACTIVE |
-		     IORESOURCE_ASSIGNED | IORESOURCE_FIXED;
+	const u32 default_decode_base = IO_APIC_ADDR;
 
-	/* GPIOBASE */
-	res = new_resource(dev, IOINDEX_SUBTRACTIVE(io_index++, 0));
-	res->base = DEFAULT_GPIOBASE;
-	res->size = DEFAULT_GPIOSIZE;
-	res->flags = IORESOURCE_IO | IORESOURCE_SUBTRACTIVE |
-		     IORESOURCE_ASSIGNED | IORESOURCE_FIXED;
-
-	res = new_resource(dev, IOINDEX_SUBTRACTIVE(io_index++, 0));
-	res->base = 0xff800000;
-	res->size = 0x00800000; /* 8 MB for flash */
-	res->flags = IORESOURCE_MEM | IORESOURCE_SUBTRACTIVE |
-		     IORESOURCE_ASSIGNED | IORESOURCE_FIXED;
-
-	res = new_resource(dev, io_index++); /* IOAPIC */
-	res->base = IO_APIC_ADDR;
-	res->size = 0x00001000;
+	/*
+	 * Just report all resources from IO-APIC base to 4GiB. Don't mark
+	 * them reserved as that may upset the OS if this range is marked
+	 * as reserved in the e820.
+	 */
+	res = new_resource(dev, OIC);
+	res->base = default_decode_base;
+	res->size = 0 - default_decode_base;
 	res->flags = IORESOURCE_MEM | IORESOURCE_ASSIGNED | IORESOURCE_FIXED;
 
-	/* Set PCH IO decode ranges if required.*/
-	if ((config->gen1_dec & 0xFFFC) > 0x1000) {
-		res = new_resource(dev, IOINDEX_SUBTRACTIVE(io_index++, 0));
-		res->base = config->gen1_dec & 0xFFFC;
-		res->size = (config->gen1_dec >> 16) & 0xFC;
-		res->flags = IORESOURCE_IO | IORESOURCE_SUBTRACTIVE |
-				 IORESOURCE_ASSIGNED | IORESOURCE_FIXED;
+	/* RCBA */
+	if (DEFAULT_RCBA < default_decode_base) {
+		res = new_resource(dev, RCBA);
+		res->base = DEFAULT_RCBA;
+		res->size = 16 * 1024;
+		res->flags = IORESOURCE_MEM | IORESOURCE_ASSIGNED |
+		             IORESOURCE_FIXED | IORESOURCE_RESERVE;
 	}
 
-	if ((config->gen2_dec & 0xFFFC) > 0x1000) {
-		res = new_resource(dev, IOINDEX_SUBTRACTIVE(io_index++, 0));
-		res->base = config->gen2_dec & 0xFFFC;
-		res->size = (config->gen2_dec >> 16) & 0xFC;
-		res->flags = IORESOURCE_IO | IORESOURCE_SUBTRACTIVE |
-				 IORESOURCE_ASSIGNED | IORESOURCE_FIXED;
+	/* Check LPC Memory Decode register. */
+	reg = pci_read_config32(dev, LGMR);
+	if (reg & 1) {
+		reg &= ~0xffff;
+		if (reg < default_decode_base) {
+			res = new_resource(dev, LGMR);
+			res->base = reg;
+			res->size = 16 * 1024;
+			res->flags = IORESOURCE_MEM | IORESOURCE_ASSIGNED |
+			             IORESOURCE_FIXED | IORESOURCE_RESERVE;
+		}
 	}
+}
 
-	if ((config->gen3_dec & 0xFFFC) > 0x1000) {
-		res = new_resource(dev, IOINDEX_SUBTRACTIVE(io_index++, 0));
-		res->base = config->gen3_dec & 0xFFFC;
-		res->size = (config->gen3_dec >> 16) & 0xFC;
-		res->flags = IORESOURCE_IO | IORESOURCE_SUBTRACTIVE |
-				 IORESOURCE_ASSIGNED | IORESOURCE_FIXED;
-	}
+/* Default IO range claimed by the LPC device. The upper bound is exclusive. */
+#define LPC_DEFAULT_IO_RANGE_LOWER 0
+#define LPC_DEFAULT_IO_RANGE_UPPER 0x1000
+
+static inline int pch_io_range_in_default(u16 base, u16 size)
+{
+	/* Does it start above the range? */
+	if (base >= LPC_DEFAULT_IO_RANGE_UPPER)
+		return 0;
+
+	/* Is it entirely contained? */
+	if (base >= LPC_DEFAULT_IO_RANGE_LOWER &&
+	    (base + size) < LPC_DEFAULT_IO_RANGE_UPPER)
+		return 1;
+
+	/* This will return not in range for partial overlaps. */
+	return 0;
+}
+
+/*
+ * Note: this function assumes there is no overlap with the default LPC device's
+ * claimed range: LPC_DEFAULT_IO_RANGE_LOWER -> LPC_DEFAULT_IO_RANGE_UPPER.
+ */
+static void pch_lpc_add_io_resource(device_t dev, u16 base, u16 size, int index)
+{
+	struct resource *res;
+
+	if (pch_io_range_in_default(base, size))
+		return;
 
-	if ((config->gen4_dec & 0xFFFC) > 0x1000) {
-		res = new_resource(dev, IOINDEX_SUBTRACTIVE(io_index++, 0));
-		res->base = config->gen4_dec & 0xFFFC;
-		res->size = (config->gen4_dec >> 16) & 0xFC;
-		res->flags = IORESOURCE_IO| IORESOURCE_SUBTRACTIVE |
-				 IORESOURCE_ASSIGNED | IORESOURCE_FIXED;
+	res = new_resource(dev, index);
+	res->base = base;
+	res->size = size;
+	res->flags = IORESOURCE_IO | IORESOURCE_ASSIGNED | IORESOURCE_FIXED;
+}
+
+static void pch_lpc_add_gen_io_resources(device_t dev, int reg_value, int index)
+{
+	/*
+	 * Check if the register is enabled. If so and the base exceeds the
+	 * device's deafult claim range add the resoure.
+	 */
+	if (reg_value & 1) {
+		u16 base = reg_value & 0xfffc;
+		u16 size = (0x3 | ((reg_value >> 16) & 0xfc)) + 1;
+		pch_lpc_add_io_resource(dev, base, size, index);
 	}
 }
 
+static void pch_lpc_add_io_resources(device_t dev)
+{
+	struct resource *res;
+	config_t *config = dev->chip_info;
+
+	/* Add the default claimed IO range for the LPC device. */
+	res = new_resource(dev, 0);
+	res->base = LPC_DEFAULT_IO_RANGE_LOWER;
+	res->size = LPC_DEFAULT_IO_RANGE_UPPER - LPC_DEFAULT_IO_RANGE_LOWER;
+	res->flags = IORESOURCE_IO | IORESOURCE_ASSIGNED | IORESOURCE_FIXED;
+
+	/* GPIOBASE */
+	pch_lpc_add_io_resource(dev, DEFAULT_GPIOBASE, DEFAULT_GPIOSIZE,
+	                        GPIO_BASE);
+
+	/* PMBASE */
+	pch_lpc_add_io_resource(dev, DEFAULT_PMBASE, 128, PMBASE);
+
+	/* LPC Generic IO Decode range. */
+	pch_lpc_add_gen_io_resources(dev, config->gen1_dec, LPC_GEN1_DEC);
+	pch_lpc_add_gen_io_resources(dev, config->gen2_dec, LPC_GEN2_DEC);
+	pch_lpc_add_gen_io_resources(dev, config->gen3_dec, LPC_GEN3_DEC);
+	pch_lpc_add_gen_io_resources(dev, config->gen4_dec, LPC_GEN4_DEC);
+}
+
+static void pch_lpc_read_resources(device_t dev)
+{
+	/* Get the normal PCI resources of this device. */
+	pci_dev_read_resources(dev);
+
+	/* Add non-standard MMIO resources. */
+	pch_lpc_add_mmio_resources(dev);
+
+	/* Add IO resources. */
+	pch_lpc_add_io_resources(dev);
+}
+
 static void pch_lpc_enable_resources(device_t dev)
 {
 	pch_decode_init(dev);
diff --git a/src/southbridge/intel/lynxpoint/pch.h b/src/southbridge/intel/lynxpoint/pch.h
index 5a3725ef29..6739843141 100644
--- a/src/southbridge/intel/lynxpoint/pch.h
+++ b/src/southbridge/intel/lynxpoint/pch.h
@@ -185,6 +185,7 @@ unsigned get_gpios(const int *gpio_num_array);
 #define LPC_GEN2_DEC		0x88 /* LPC IF Generic Decode Range 2 */
 #define LPC_GEN3_DEC		0x8c /* LPC IF Generic Decode Range 3 */
 #define LPC_GEN4_DEC		0x90 /* LPC IF Generic Decode Range 4 */
+#define LGMR			0x98 /* LPC Generic Memory Range */
 
 /* PCI Configuration Space (D31:F1): IDE */
 #define PCH_IDE_DEV		PCI_DEV(0, 0x1f, 1)