1 files changed, 311 insertions, 0 deletions
diff --git a/arch/x86/pci/olpc.c b/arch/x86/pci/olpc.c
new file mode 100644
index 0000000000..f3aab76e35
--- /dev/null
+++ b/arch/x86/pci/olpc.c
@@ -0,0 +1,311 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Low-level PCI config space access for OLPC systems who lack the VSA
+ * PCI virtualization software.
+ *
+ * Copyright © 2006  Advanced Micro Devices, Inc.
+ *
+ * The AMD Geode chipset (ie: GX2 processor, cs5536 I/O companion device)
+ * has some I/O functions (display, southbridge, sound, USB HCIs, etc)
+ * that more or less behave like PCI devices, but the hardware doesn't
+ * directly implement the PCI configuration space headers.  AMD provides
+ * "VSA" (Virtual System Architecture) software that emulates PCI config
+ * space for these devices, by trapping I/O accesses to PCI config register
+ * (CF8/CFC) and running some code in System Management Mode interrupt state.
+ * On the OLPC platform, we don't want to use that VSA code because
+ * (a) it slows down suspend/resume, and (b) recompiling it requires special
+ * compilers that are hard to get.  So instead of letting the complex VSA
+ * code simulate the PCI config registers for the on-chip devices, we
+ * just simulate them the easy way, by inserting the code into the
+ * pci_write_config and pci_read_config path.  Most of the config registers
+ * are read-only anyway, so the bulk of the simulation is just table lookup.
+ */
+
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <asm/olpc.h>
+#include <asm/geode.h>
+#include <asm/pci_x86.h>
+
+/*
+ * In the tables below, the first two line (8 longwords) are the
+ * size masks that are used when the higher level PCI code determines
+ * the size of the region by writing ~0 to a base address register
+ * and reading back the result.
+ *
+ * The following lines are the values that are read during normal
+ * PCI config access cycles, i.e. not after just having written
+ * ~0 to a base address register.
+ */
+
+static const uint32_t lxnb_hdr[] = {  /* dev 1 function 0 - devfn = 8 */
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+
+	0x281022, 0x2200005, 0x6000021, 0x80f808,	/* AMD Vendor ID */
+	0x0,	0x0,	0x0,	0x0,   /* No virtual registers, hence no BAR */
+	0x0,	0x0,	0x0,	0x28100b,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+};
+
+static const uint32_t gxnb_hdr[] = {  /* dev 1 function 0 - devfn = 8 */
+	0xfffffffd, 0x0, 0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+
+	0x28100b, 0x2200005, 0x6000021, 0x80f808,	/* NSC Vendor ID */
+	0xac1d,	0x0,	0x0,	0x0,  /* I/O BAR - base of virtual registers */
+	0x0,	0x0,	0x0,	0x28100b,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+};
+
+static const uint32_t lxfb_hdr[] = {  /* dev 1 function 1 - devfn = 9 */
+	0xff000008, 0xffffc000, 0xffffc000, 0xffffc000,
+	0xffffc000,	0x0,	0x0,	0x0,
+
+	0x20811022, 0x2200003, 0x3000000, 0x0,		/* AMD Vendor ID */
+	0xfd000000, 0xfe000000, 0xfe004000, 0xfe008000, /* FB, GP, VG, DF */
+	0xfe00c000, 0x0, 0x0,	0x30100b,		/* VIP */
+	0x0,	0x0,	0x0,	0x10e,	   /* INTA, IRQ14 for graphics accel */
+	0x0,	0x0,	0x0,	0x0,
+	0x3d0,	0x3c0,	0xa0000, 0x0,	    /* VG IO, VG IO, EGA FB, MONO FB */
+	0x0,	0x0,	0x0,	0x0,
+};
+
+static const uint32_t gxfb_hdr[] = {  /* dev 1 function 1 - devfn = 9 */
+	0xff800008, 0xffffc000, 0xffffc000, 0xffffc000,
+	0x0,	0x0,	0x0,	0x0,
+
+	0x30100b, 0x2200003, 0x3000000, 0x0,		/* NSC Vendor ID */
+	0xfd000000, 0xfe000000, 0xfe004000, 0xfe008000,	/* FB, GP, VG, DF */
+	0x0,	0x0,	0x0,	0x30100b,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+	0x3d0,	0x3c0,	0xa0000, 0x0,  	    /* VG IO, VG IO, EGA FB, MONO FB */
+	0x0,	0x0,	0x0,	0x0,
+};
+
+static const uint32_t aes_hdr[] = {	/* dev 1 function 2 - devfn = 0xa */
+	0xffffc000, 0x0, 0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+
+	0x20821022, 0x2a00006, 0x10100000, 0x8,		/* NSC Vendor ID */
+	0xfe010000, 0x0, 0x0,	0x0,			/* AES registers */
+	0x0,	0x0,	0x0,	0x20821022,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+};
+
+
+static const uint32_t isa_hdr[] = {  /* dev f function 0 - devfn = 78 */
+	0xfffffff9, 0xffffff01, 0xffffffc1, 0xffffffe1,
+	0xffffff81, 0xffffffc1, 0x0, 0x0,
+
+	0x20901022, 0x2a00049, 0x6010003, 0x802000,
+	0x18b1,	0x1001,	0x1801,	0x1881,	/* SMB-8   GPIO-256 MFGPT-64  IRQ-32 */
+	0x1401,	0x1841,	0x0,	0x20901022,		/* PMS-128 ACPI-64 */
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0xaa5b,			/* IRQ steering */
+	0x0,	0x0,	0x0,	0x0,
+};
+
+static const uint32_t ac97_hdr[] = {  /* dev f function 3 - devfn = 7b */
+	0xffffff81, 0x0, 0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+
+	0x20931022, 0x2a00041, 0x4010001, 0x0,
+	0x1481,	0x0,	0x0,	0x0,			/* I/O BAR-128 */
+	0x0,	0x0,	0x0,	0x20931022,
+	0x0,	0x0,	0x0,	0x205,			/* IntB, IRQ5 */
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+};
+
+static const uint32_t ohci_hdr[] = {  /* dev f function 4 - devfn = 7c */
+	0xfffff000, 0x0, 0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+
+	0x20941022, 0x2300006, 0xc031002, 0x0,
+	0xfe01a000, 0x0, 0x0,	0x0,			/* MEMBAR-1000 */
+	0x0,	0x0,	0x0,	0x20941022,
+	0x0,	0x40,	0x0,	0x40a,			/* CapPtr INT-D, IRQA */
+	0xc8020001, 0x0, 0x0,	0x0,	/* Capabilities - 40 is R/O,
+					   44 is mask 8103 (power control) */
+	0x0,	0x0,	0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+};
+
+static const uint32_t ehci_hdr[] = {  /* dev f function 4 - devfn = 7d */
+	0xfffff000, 0x0, 0x0,	0x0,
+	0x0,	0x0,	0x0,	0x0,
+
+	0x20951022, 0x2300006, 0xc032002, 0x0,
+	0xfe01b000, 0x0, 0x0,	0x0,			/* MEMBAR-1000 */
+	0x0,	0x0,	0x0,	0x20951022,
+	0x0,	0x40,	0x0,	0x40a,			/* CapPtr INT-D, IRQA */
+	0xc8020001, 0x0, 0x0,	0x0,	/* Capabilities - 40 is R/O, 44 is
+					   mask 8103 (power control) */
+#if 0
+	0x1,	0x40080000, 0x0, 0x0,	/* EECP - see EHCI spec section 2.1.7 */
+#endif
+	0x01000001, 0x0, 0x0,	0x0,	/* EECP - see EHCI spec section 2.1.7 */
+	0x2020,	0x0,	0x0,	0x0,	/* (EHCI page 8) 60 SBRN (R/O),
+					   61 FLADJ (R/W), PORTWAKECAP  */
+};
+
+static uint32_t ff_loc = ~0;
+static uint32_t zero_loc;
+static int bar_probing;		/* Set after a write of ~0 to a BAR */
+static int is_lx;
+
+#define NB_SLOT 0x1	/* Northbridge - GX chip - Device 1 */
+#define SB_SLOT 0xf	/* Southbridge - CS5536 chip - Device F */
+
+static int is_simulated(unsigned int bus, unsigned int devfn)
+{
+	return (!bus && ((PCI_SLOT(devfn) == NB_SLOT) ||
+			(PCI_SLOT(devfn) == SB_SLOT)));
+}
+
+static uint32_t *hdr_addr(const uint32_t *hdr, int reg)
+{
+	uint32_t addr;
+
+	/*
+	 * This is a little bit tricky.  The header maps consist of
+	 * 0x20 bytes of size masks, followed by 0x70 bytes of header data.
+	 * In the normal case, when not probing a BAR's size, we want
+	 * to access the header data, so we add 0x20 to the reg offset,
+	 * thus skipping the size mask area.
+	 * In the BAR probing case, we want to access the size mask for
+	 * the BAR, so we subtract 0x10 (the config header offset for
+	 * BAR0), and don't skip the size mask area.
+	 */
+
+	addr = (uint32_t)hdr + reg + (bar_probing ? -0x10 : 0x20);
+
+	bar_probing = 0;
+	return (uint32_t *)addr;
+}
+
+static int pci_olpc_read(unsigned int seg, unsigned int bus,
+		unsigned int devfn, int reg, int len, uint32_t *value)
+{
+	uint32_t *addr;
+
+	WARN_ON(seg);
+
+	/* Use the hardware mechanism for non-simulated devices */
+	if (!is_simulated(bus, devfn))
+		return pci_direct_conf1.read(seg, bus, devfn, reg, len, value);
+
+	/*
+	 * No device has config registers past 0x70, so we save table space
+	 * by not storing entries for the nonexistent registers
+	 */
+	if (reg >= 0x70)
+		addr = &zero_loc;
+	else {
+		switch (devfn) {
+		case  0x8:
+			addr = hdr_addr(is_lx ? lxnb_hdr : gxnb_hdr, reg);
+			break;
+		case  0x9:
+			addr = hdr_addr(is_lx ? lxfb_hdr : gxfb_hdr, reg);
+			break;
+		case  0xa:
+			addr = is_lx ? hdr_addr(aes_hdr, reg) : &ff_loc;
+			break;
+		case 0x78:
+			addr = hdr_addr(isa_hdr, reg);
+			break;
+		case 0x7b:
+			addr = hdr_addr(ac97_hdr, reg);
+			break;
+		case 0x7c:
+			addr = hdr_addr(ohci_hdr, reg);
+			break;
+		case 0x7d:
+			addr = hdr_addr(ehci_hdr, reg);
+			break;
+		default:
+			addr = &ff_loc;
+			break;
+		}
+	}
+	switch (len) {
+	case 1:
+		*value = *(uint8_t *)addr;
+		break;
+	case 2:
+		*value = *(uint16_t *)addr;
+		break;
+	case 4:
+		*value = *addr;
+		break;
+	default:
+		BUG();
+	}
+
+	return 0;
+}
+
+static int pci_olpc_write(unsigned int seg, unsigned int bus,
+		unsigned int devfn, int reg, int len, uint32_t value)
+{
+	WARN_ON(seg);
+
+	/* Use the hardware mechanism for non-simulated devices */
+	if (!is_simulated(bus, devfn))
+		return pci_direct_conf1.write(seg, bus, devfn, reg, len, value);
+
+	/* XXX we may want to extend this to simulate EHCI power management */
+
+	/*
+	 * Mostly we just discard writes, but if the write is a size probe
+	 * (i.e. writing ~0 to a BAR), we remember it and arrange to return
+	 * the appropriate size mask on the next read.  This is cheating
+	 * to some extent, because it depends on the fact that the next
+	 * access after such a write will always be a read to the same BAR.
+	 */
+
+	if ((reg >= 0x10) && (reg < 0x2c)) {
+		/* write is to a BAR */
+		if (value == ~0)
+			bar_probing = 1;
+	} else {
+		/*
+		 * No warning on writes to ROM BAR, CMD, LATENCY_TIMER,
+		 * CACHE_LINE_SIZE, or PM registers.
+		 */
+		if ((reg != PCI_ROM_ADDRESS) && (reg != PCI_COMMAND_MASTER) &&
+				(reg != PCI_LATENCY_TIMER) &&
+				(reg != PCI_CACHE_LINE_SIZE) && (reg != 0x44))
+			printk(KERN_WARNING "OLPC PCI: Config write to devfn"
+				" %x reg %x value %x\n", devfn, reg, value);
+	}
+
+	return 0;
+}
+
+static const struct pci_raw_ops pci_olpc_conf = {
+	.read =	pci_olpc_read,
+	.write = pci_olpc_write,
+};
+
+int __init pci_olpc_init(void)
+{
+	printk(KERN_INFO "PCI: Using configuration type OLPC XO-1\n");
+	raw_pci_ops = &pci_olpc_conf;
+	is_lx = is_geode_lx();
+	return 0;
+}