1 files changed, 265 insertions, 0 deletions
diff --git a/src/drivers/bus/ecam.c b/src/drivers/bus/ecam.c
new file mode 100644
index 000000000..f7ba2db7f
--- /dev/null
+++ b/src/drivers/bus/ecam.c
@@ -0,0 +1,265 @@
+/*
+ * Copyright (C) 2022 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <errno.h>
+#include <ipxe/uaccess.h>
+#include <ipxe/ecam.h>
+
+/** @file
+ *
+ * PCI Enhanced Configuration Access Mechanism (ECAM)
+ *
+ */
+
+/** Cached mapped ECAM allocation */
+static struct ecam_mapping ecam;
+
+/**
+ * Find lowest ECAM allocation not below a given PCI bus:dev.fn address
+ *
+ * @v busdevfn		PCI bus:dev.fn address
+ * @v range		PCI device address range to fill in
+ * @v alloc		ECAM allocation to fill in, or NULL
+ * @ret rc		Return status code
+ */
+static int ecam_find ( uint32_t busdevfn, struct pci_range *range,
+		       struct ecam_allocation *alloc ) {
+	struct ecam_allocation tmp;
+	unsigned int best = 0;
+	unsigned int offset;
+	unsigned int count;
+	unsigned int index;
+	userptr_t mcfg;
+	uint32_t length;
+	uint32_t start;
+
+	/* Return empty range on error */
+	range->count = 0;
+
+	/* Locate MCFG table */
+	mcfg = acpi_table ( ECAM_SIGNATURE, 0 );
+	if ( ! mcfg ) {
+		DBGC ( &ecam, "ECAM found no MCFG table\n" );
+		return -ENOTSUP;
+	}
+
+	/* Get length of table */
+	copy_from_user ( &length, mcfg,
+			 offsetof ( struct ecam_table, acpi.length ),
+			 sizeof ( length ) );
+
+	/* Iterate over allocations */
+	for ( offset = offsetof ( struct ecam_table, alloc ) ;
+	      ( offset + sizeof ( tmp ) ) <= le32_to_cpu ( length ) ;
+	      offset += sizeof ( tmp ) ) {
+
+		/* Read allocation */
+		copy_from_user ( &tmp, mcfg, offset, sizeof ( tmp ) );
+		DBGC2 ( &ecam, "ECAM %04x:[%02x-%02x] has base %08llx\n",
+			le16_to_cpu ( tmp.segment ), tmp.start, tmp.end,
+			( ( unsigned long long ) le64_to_cpu ( tmp.base ) ) );
+		start = PCI_BUSDEVFN ( le16_to_cpu ( tmp.segment ),
+				       tmp.start, 0, 0 );
+		count = PCI_BUSDEVFN ( 0, ( tmp.end - tmp.start + 1 ), 0, 0 );
+
+		/* Check for a matching or new closest allocation */
+		index = ( busdevfn - start );
+		if ( ( index < count ) || ( index > best ) ) {
+			if ( alloc )
+				memcpy ( alloc, &tmp, sizeof ( *alloc ) );
+			range->start = start;
+			range->count = count;
+			best = index;
+		}
+
+		/* Stop if this range contains the target bus:dev.fn address */
+		if ( index < count )
+			return 0;
+	}
+
+	return ( best ? 0 : -ENOENT );
+}
+
+/**
+ * Find next PCI bus:dev.fn address range in system
+ *
+ * @v busdevfn		Starting PCI bus:dev.fn address
+ * @v range		PCI bus:dev.fn address range to fill in
+ */
+static void ecam_discover ( uint32_t busdevfn, struct pci_range *range ) {
+
+	/* Find new range, if any */
+	ecam_find ( busdevfn, range, NULL );
+}
+
+/**
+ * Access configuration space for PCI device
+ *
+ * @v pci		PCI device
+ * @ret rc		Return status code
+ */
+static int ecam_access ( struct pci_device *pci ) {
+	uint64_t base;
+	size_t len;
+	int rc;
+
+	/* Reuse mapping if possible */
+	if ( ( pci->busdevfn - ecam.range.start ) < ecam.range.count )
+		return 0;
+
+	/* Clear any existing mapping */
+	if ( ecam.regs ) {
+		iounmap ( ecam.regs );
+		ecam.regs = NULL;
+	}
+
+	/* Find allocation for this PCI device */
+	if ( ( rc = ecam_find ( pci->busdevfn, &ecam.range,
+				&ecam.alloc ) ) != 0 ) {
+		DBGC ( &ecam, "ECAM found no allocation for " PCI_FMT ": %s\n",
+		       PCI_ARGS ( pci ), strerror ( rc ) );
+		goto err_find;
+	}
+	if ( ecam.range.start > pci->busdevfn ) {
+		DBGC ( &ecam, "ECAM found no allocation for " PCI_FMT "\n",
+		       PCI_ARGS ( pci ) );
+		goto err_find;
+	}
+
+	/* Map configuration space for this allocation */
+	base = le64_to_cpu ( ecam.alloc.base );
+	len = ( ecam.range.count * ECAM_SIZE );
+	ecam.regs = ioremap ( base, len );
+	if ( ! ecam.regs ) {
+		DBGC ( &ecam, "ECAM %04x:[%02x-%02x] could not map "
+		       "[%08llx,%08llx)\n", le16_to_cpu ( ecam.alloc.segment ),
+		       ecam.alloc.start, ecam.alloc.end, base, ( base + len ) );
+		rc = -ENODEV;
+		goto err_ioremap;
+	}
+
+	/* Populate cached mapping */
+	DBGC ( &ecam, "ECAM %04x:[%02x-%02x] mapped [%08llx,%08llx) -> %p\n",
+	       le16_to_cpu ( ecam.alloc.segment ), ecam.alloc.start,
+	       ecam.alloc.end, base, ( base + len ), ecam.regs );
+	return 0;
+
+	iounmap ( ecam.regs );
+ err_ioremap:
+ err_find:
+	ecam.range.count = 0;
+	return rc;
+}
+
+/**
+ * Read from PCI configuration space
+ *
+ * @v pci	PCI device
+ * @v location	Offset and length within PCI configuration space
+ * @v value	Value read
+ * @ret rc	Return status code
+ */
+int ecam_read ( struct pci_device *pci, unsigned int location, void *value ) {
+	unsigned int where = ECAM_WHERE ( location );
+	unsigned int len = ECAM_LEN ( location );
+	unsigned int index;
+	void *addr;
+	int rc;
+
+	/* Return all-ones on error */
+	memset ( value, 0xff, len );
+
+	/* Access configuration space */
+	if ( ( rc = ecam_access ( pci ) ) != 0 )
+		return rc;
+
+	/* Read from address */
+	index = ( pci->busdevfn - ecam.range.start );
+	addr = ( ecam.regs + ( index * ECAM_SIZE ) + where );
+	switch ( len ) {
+	case 4:
+		*( ( uint32_t *) value ) = readl ( addr );
+		break;
+	case 2:
+		*( ( uint16_t *) value ) = readw ( addr );
+		break;
+	case 1:
+		*( ( uint8_t *) value ) = readb ( addr );
+		break;
+	default:
+		assert ( 0 );
+	}
+
+	return 0;
+}
+
+/**
+ * Write to PCI configuration space
+ *
+ * @v pci	PCI device
+ * @v location	Offset and length within PCI configuration space
+ * @v value	Value to write
+ * @ret rc	Return status code
+ */
+int ecam_write ( struct pci_device *pci, unsigned int location,
+		 unsigned long value ) {
+	unsigned int where = ECAM_WHERE ( location );
+	unsigned int len = ECAM_LEN ( location );
+	unsigned int index;
+	void *addr;
+	int rc;
+
+	/* Access configuration space */
+	if ( ( rc = ecam_access ( pci ) ) != 0 )
+		return rc;
+
+	/* Read from address */
+	index = ( pci->busdevfn - ecam.range.start );
+	addr = ( ecam.regs + ( index * ECAM_SIZE ) + where );
+	switch ( len ) {
+	case 4:
+		writel ( value, addr );
+		break;
+	case 2:
+		writew ( value, addr );
+		break;
+	case 1:
+		writeb ( value, addr );
+		break;
+	default:
+		assert ( 0 );
+	}
+
+	return 0;
+}
+
+PROVIDE_PCIAPI ( ecam, pci_discover, ecam_discover );
+PROVIDE_PCIAPI_INLINE ( ecam, pci_read_config_byte );
+PROVIDE_PCIAPI_INLINE ( ecam, pci_read_config_word );
+PROVIDE_PCIAPI_INLINE ( ecam, pci_read_config_dword );
+PROVIDE_PCIAPI_INLINE ( ecam, pci_write_config_byte );
+PROVIDE_PCIAPI_INLINE ( ecam, pci_write_config_word );
+PROVIDE_PCIAPI_INLINE ( ecam, pci_write_config_dword );
+PROVIDE_PCIAPI_INLINE ( ecam, pci_ioremap );