soc/intel/skylake: Generate ACPI DMAR table

If the SoC is VT-d capable, write an ACPI DMAR table. The entry for the
GFXVTBAR is only generated if the IGD is enabled.

Change-Id: I8176401dd19aee7ad09a8a145b7a3801fe5b2ae1
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/21588
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Youness Alaoui <snifikino@gmail.com>

src/soc/intel/skylake/acpi.c

@@ -34,14 +34,17 @@
 #include <intelblocks/lpc_lib.h>
 #include <intelblocks/sgx.h>
 #include <intelblocks/uart.h>
+#include <intelblocks/systemagent.h>
 #include <soc/intel/common/acpi.h>
 #include <soc/acpi.h>
 #include <soc/cpu.h>
 #include <soc/iomap.h>
 #include <soc/msr.h>
+#include <soc/p2sb.h>
 #include <soc/pci_devs.h>
 #include <soc/pm.h>
 #include <soc/ramstage.h>
+#include <soc/systemagent.h>
 #include <string.h>
 #include <types.h>
 #include <vendorcode/google/chromeos/gnvs.h>
@@ -534,6 +537,74 @@ void generate_cpu_entries(device_t device)
 	}
 }
 
+static unsigned long acpi_fill_dmar(unsigned long current)
+{
+	struct device *const igfx_dev = dev_find_slot(0, SA_DEVFN_IGD);
+	const u32 gfx_vtbar = MCHBAR32(GFXVTBAR) & ~0xfff;
+	const bool gfxvten = MCHBAR32(GFXVTBAR) & 1;
+
+	/* iGFX has to be enabled, GFXVTBAR set and in 32-bit space. */
+	if (igfx_dev && igfx_dev->enabled && gfxvten &&
+	    gfx_vtbar && !MCHBAR32(GFXVTBAR + 4)) {
+		const unsigned long tmp = current;
+
+		current += acpi_create_dmar_drhd(current, 0, 0, gfx_vtbar);
+		current += acpi_create_dmar_drhd_ds_pci(current, 0, 2, 0);
+
+		acpi_dmar_drhd_fixup(tmp, current);
+	}
+
+	struct device *const p2sb_dev = dev_find_slot(0, PCH_DEVFN_P2SB);
+	const u32 vtvc0bar = MCHBAR32(VTVC0BAR) & ~0xfff;
+	const bool vtvc0en = MCHBAR32(VTVC0BAR) & 1;
+
+	/* General VTBAR has to be set and in 32-bit space. */
+	if (p2sb_dev && vtvc0bar && vtvc0en && !MCHBAR32(VTVC0BAR + 4)) {
+		const unsigned long tmp = current;
+
+		/* P2SB may already be hidden. There's no clear rule, when. */
+		const u8 p2sb_hidden =
+			pci_read_config8(p2sb_dev, PCH_P2SB_E0 + 1);
+		pci_write_config8(p2sb_dev, PCH_P2SB_E0 + 1, 0);
+
+		const u16 ibdf = pci_read_config16(p2sb_dev, PCH_P2SB_IBDF);
+		const u16 hbdf = pci_read_config16(p2sb_dev, PCH_P2SB_HBDF);
+
+		pci_write_config8(p2sb_dev, PCH_P2SB_E0 + 1, p2sb_hidden);
+
+		current += acpi_create_dmar_drhd(current,
+				DRHD_INCLUDE_PCI_ALL, 0, vtvc0bar);
+		current += acpi_create_dmar_drhd_ds_ioapic(current,
+				2, ibdf >> 8, PCI_SLOT(ibdf), PCI_FUNC(ibdf));
+		current += acpi_create_dmar_drhd_ds_msi_hpet(current,
+				0, hbdf >> 8, PCI_SLOT(hbdf), PCI_FUNC(hbdf));
+
+		acpi_dmar_drhd_fixup(tmp, current);
+	}
+
+	return current;
+}
+
+unsigned long northbridge_write_acpi_tables(struct device *const dev,
+					    unsigned long current,
+					    struct acpi_rsdp *const rsdp)
+{
+	const struct soc_intel_skylake_config *const config = dev->chip_info;
+	acpi_dmar_t *const dmar = (acpi_dmar_t *)current;
+
+	/* Create DMAR table only if we have VT-d capability. */
+	if ((config && config->ignore_vtd) || !soc_is_vtd_capable())
+		return current;
+
+	printk(BIOS_DEBUG, "ACPI:    * DMAR\n");
+	acpi_create_dmar(dmar, DMAR_INTR_REMAP, acpi_fill_dmar);
+	current += dmar->header.length;
+	current = acpi_align_current(current);
+	acpi_add_table(rsdp, dmar);
+
+	return current;
+}
+
 unsigned long acpi_madt_irq_overrides(unsigned long current)
 {
 	int sci = acpi_sci_irq();

src/soc/intel/skylake/chip_fsp20.c

@@ -60,6 +60,7 @@ static struct device_operations pci_domain_ops = {
 	.scan_bus         = &pci_domain_scan_bus,
 	.ops_pci_bus      = &pci_bus_default_ops,
 #if IS_ENABLED(CONFIG_HAVE_ACPI_TABLES)
+	.write_acpi_tables	= &northbridge_write_acpi_tables,
 	.acpi_name		= &soc_acpi_name,
 #endif
 };

src/soc/intel/skylake/include/soc/acpi.h

@@ -32,5 +32,7 @@ void acpi_mainboard_gnvs(global_nvs_t *gnvs);
 void southbridge_inject_dsdt(device_t device);
 unsigned long southbridge_write_acpi_tables(device_t device,
 	unsigned long current, struct acpi_rsdp *rsdp);
+unsigned long northbridge_write_acpi_tables(struct device *,
+	unsigned long current, struct acpi_rsdp *);
 
 #endif /* _SOC_ACPI_H_ */

src/soc/intel/skylake/include/soc/p2sb.h

@@ -19,6 +19,9 @@
 #define HPTC_OFFSET		0x60
 #define HPTC_ADDR_ENABLE_BIT	(1 << 7)
 
+#define PCH_P2SB_IBDF			0x6c
+#define PCH_P2SB_HBDF			0x70
+
 #define PCH_P2SB_EPMASK0		0xB0
 #define PCH_P2SB_EPMASK(mask_number)	(PCH_P2SB_EPMASK0 + ((mask_number) * 4))