soc/intel/broadwell: Define and use MMCONF_BUS_NUMBER

Note that ACPI MCFG generation reported too many busses.

Change-Id: I5acd26bac675cc818df46f60887f90b76f4580a2
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50034
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/broadwell/Kconfig

@@ -77,9 +77,11 @@ config VBOOT
 	select VBOOT_STARTS_IN_ROMSTAGE if !BROADWELL_VBOOT_IN_BOOTBLOCK
 
 config MMCONF_BASE_ADDRESS
-	hex
 	default 0xf0000000
 
+config MMCONF_BUS_NUMBER
+	default 64
+
 config VGA_BIOS_ID
 	string
 	default "8086,0406"

src/soc/intel/broadwell/acpi.c

@@ -25,7 +25,8 @@
 unsigned long acpi_fill_mcfg(unsigned long current)
 {
 	current += acpi_create_mcfg_mmconfig((acpi_mcfg_mmconfig_t *)current,
-					     MCFG_BASE_ADDRESS, 0, 0, 255);
+					     CONFIG_MMCONF_BASE_ADDRESS, 0, 0,
+					     CONFIG_MMCONF_BUS_NUMBER - 1);
 	return current;
 }
 

src/soc/intel/broadwell/acpi/hostbridge.asl

@@ -178,7 +178,7 @@ Device (PDRC)
 		Memory32Fixed (ReadWrite, MCH_BASE_ADDRESS, MCH_BASE_SIZE)
 		Memory32Fixed (ReadWrite, DMI_BASE_ADDRESS, DMI_BASE_SIZE)
 		Memory32Fixed (ReadWrite, EP_BASE_ADDRESS, EP_BASE_SIZE)
-		Memory32Fixed (ReadWrite, MCFG_BASE_ADDRESS, MCFG_BASE_SIZE)
+		Memory32Fixed (ReadWrite, CONFIG_MMCONF_BASE_ADDRESS, CONFIG_MMCONF_LENGTH)
 		Memory32Fixed (ReadWrite, EDRAM_BASE_ADDRESS, EDRAM_BASE_SIZE)
 		Memory32Fixed (ReadWrite, GDXC_BASE_ADDRESS, GDXC_BASE_SIZE)
 	})

src/soc/intel/broadwell/bootblock.c

@@ -1,28 +1,34 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <arch/bootblock.h>
+#include <assert.h>
 #include <device/pci_ops.h>
 #include <soc/pci_devs.h>
 #include <soc/systemagent.h>
 
+static uint32_t encode_pciexbar_length(void)
+{
+	switch (CONFIG_MMCONF_BUS_NUMBER) {
+		case 256: return 0 << 1;
+		case 128: return 1 << 1;
+		case  64: return 2 << 1;
+		default:  return dead_code_t(uint32_t);
+	}
+}
+
 void bootblock_early_northbridge_init(void)
 {
-	uint32_t reg;
-
 	/*
-	 * The "io" variant of the config access is explicitly used to
+	 * The "io" variant of the config access is explicitly used to setup the
-	 * setup the PCIEXBAR because CONFIG(MMCONF_SUPPORT) is set to
+	 * PCIEXBAR because CONFIG(MMCONF_SUPPORT) is set to true. That way, all
-	 * true. That way all subsequent non-explicit config accesses use
+	 * subsequent non-explicit config accesses use MCFG. This code also assumes
-	 * MCFG. This code also assumes that bootblock_northbridge_init() is
+	 * that bootblock_northbridge_init() is the first thing called in the non-asm
-	 * the first thing called in the non-asm boot block code. The final
+	 * boot block code. The final assumption is that no assembly code is using the
-	 * assumption is that no assembly code is using the
 	 * CONFIG(MMCONF_SUPPORT) option to do PCI config accesses.
 	 *
-	 * The PCIEXBAR is assumed to live in the memory mapped IO space under
+	 * The PCIEXBAR is assumed to live in the memory mapped IO space under 4GiB.
-	 * 4GiB.
 	 */
-	reg = 0;
+	const uint32_t reg = CONFIG_MMCONF_BASE_ADDRESS | encode_pciexbar_length() | 1;
-	pci_io_write_config32(SA_DEV_ROOT, PCIEXBAR + 4, reg);
+	pci_io_write_config32(SA_DEV_ROOT, PCIEXBAR + 4, 0);
-	reg = CONFIG_MMCONF_BASE_ADDRESS | 4 | 1; /* 64MiB - 0-63 buses. */
 	pci_io_write_config32(SA_DEV_ROOT, PCIEXBAR, reg);
 }

src/soc/intel/broadwell/include/soc/iomap.h

@@ -3,9 +3,6 @@
 #ifndef _BROADWELL_IOMAP_H_
 #define _BROADWELL_IOMAP_H_
 
-#define MCFG_BASE_ADDRESS	CONFIG_MMCONF_BASE_ADDRESS
-#define MCFG_BASE_SIZE		0x4000000
-
 #define MCH_BASE_ADDRESS	0xfed10000
 #define MCH_BASE_SIZE		0x8000
 

src/soc/intel/broadwell/pei_data.c

@@ -15,7 +15,7 @@ void broadwell_fill_pei_data(struct pei_data *pei_data)
 	pei_data->pei_version = PEI_VERSION;
 	pei_data->board_type = BOARD_TYPE_ULT;
 	pei_data->usbdebug = CONFIG(USBDEBUG);
-	pei_data->pciexbar = MCFG_BASE_ADDRESS;
+	pei_data->pciexbar = CONFIG_MMCONF_BASE_ADDRESS;
 	pei_data->smbusbar = CONFIG_FIXED_SMBUS_IO_BASE;
 	pei_data->ehcibar = EARLY_EHCI_BAR;
 	pei_data->xhcibar = EARLY_XHCI_BAR;