[PATCH] ioc4: Enable build on non-SN2

The SGI PCI-RT card, based on the SGI IOC4 chip, will be made available on
Altix XE (x86_64) platforms in the near future.  As such it is now a
misnomer for the IOC4 base device driver to live under drivers/sn, and
would complicate builds for non-SN2.

This patch moves the IOC4 base driver code from drivers/sn to drivers/misc,
and updates the associated Makefiles and Kconfig files to allow building on
non-SN2 configs.  Due to the resulting change in link order, it is now
necessary to use late_initcall() for IOC4 subdriver initialization.

[akpm@osdl.org: __udivdi3 fix]
[akpm@osdl.org: fix default in Kconfig]
Acked-by: Pat Gefre <pfg@sgi.com>
Acked-by: Jeremy Higdon <jeremy@sgi.com>
Signed-off-by: Brent Casavant <bcasavan@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 485 insertions, 0 deletions

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index fa7acc2..b6c045d 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -28,6 +28,17 @@ config IBM_ASM
 
 	  If unsure, say N.
 
+config SGI_IOC4
+	tristate "SGI IOC4 Base IO support"
+	---help---
+	  This option enables basic support for the IOC4 chip on certain
+	  SGI IO controller cards (IO9, IO10, and PCI-RT).  This option
+	  does not enable any specific functions on such a card, but provides
+	  necessary infrastructure for other drivers to utilize.
+
+	  If you have an SGI Altix with an IOC4-based card say Y.
+	  Otherwise say N.
+
 config TIFM_CORE
 	tristate "TI Flash Media interface support (EXPERIMENTAL)"
 	depends on EXPERIMENTAL
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 9a91c1e..c9e98ab 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_MSI_LAPTOP)     += msi-laptop.o
 obj-$(CONFIG_LKDTM)		+= lkdtm.o
 obj-$(CONFIG_TIFM_CORE)       	+= tifm_core.o
 obj-$(CONFIG_TIFM_7XX1)       	+= tifm_7xx1.o
+obj-$(CONFIG_SGI_IOC4)		+= ioc4.o
diff --git a/drivers/misc/ioc4.c b/drivers/misc/ioc4.c
new file mode 100644
index 0000000..1c3c14a
--- /dev/null
+++ b/drivers/misc/ioc4.c
@@ -0,0 +1,473 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2005-2006 Silicon Graphics, Inc.  All Rights Reserved.
+ */
+
+/* This file contains the master driver module for use by SGI IOC4 subdrivers.
+ *
+ * It allocates any resources shared between multiple subdevices, and
+ * provides accessor functions (where needed) and the like for those
+ * resources.  It also provides a mechanism for the subdevice modules
+ * to support loading and unloading.
+ *
+ * Non-shared resources (e.g. external interrupt A_INT_OUT register page
+ * alias, serial port and UART registers) are handled by the subdevice
+ * modules themselves.
+ *
+ * This is all necessary because IOC4 is not implemented as a multi-function
+ * PCI device, but an amalgamation of disparate registers for several
+ * types of device (ATA, serial, external interrupts).  The normal
+ * resource management in the kernel doesn't have quite the right interfaces
+ * to handle this situation (e.g. multiple modules can't claim the same
+ * PCI ID), thus this IOC4 master module.
+ */
+
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/ioc4.h>
+#include <linux/ktime.h>
+#include <linux/mutex.h>
+#include <linux/time.h>
+
+/***************
+ * Definitions *
+ ***************/
+
+/* Tweakable values */
+
+/* PCI bus speed detection/calibration */
+#define IOC4_CALIBRATE_COUNT 63		/* Calibration cycle period */
+#define IOC4_CALIBRATE_CYCLES 256	/* Average over this many cycles */
+#define IOC4_CALIBRATE_DISCARD 2	/* Discard first few cycles */
+#define IOC4_CALIBRATE_LOW_MHZ 25	/* Lower bound on bus speed sanity */
+#define IOC4_CALIBRATE_HIGH_MHZ 75	/* Upper bound on bus speed sanity */
+#define IOC4_CALIBRATE_DEFAULT_MHZ 66	/* Assumed if sanity check fails */
+
+/************************
+ * Submodule management *
+ ************************/
+
+static DEFINE_MUTEX(ioc4_mutex);
+
+static LIST_HEAD(ioc4_devices);
+static LIST_HEAD(ioc4_submodules);
+
+/* Register an IOC4 submodule */
+int
+ioc4_register_submodule(struct ioc4_submodule *is)
+{
+	struct ioc4_driver_data *idd;
+
+	mutex_lock(&ioc4_mutex);
+	list_add(&is->is_list, &ioc4_submodules);
+
+	/* Initialize submodule for each IOC4 */
+	if (!is->is_probe)
+		goto out;
+
+	list_for_each_entry(idd, &ioc4_devices, idd_list) {
+		if (is->is_probe(idd)) {
+			printk(KERN_WARNING
+			       "%s: IOC4 submodule %s probe failed "
+			       "for pci_dev %s",
+			       __FUNCTION__, module_name(is->is_owner),
+			       pci_name(idd->idd_pdev));
+		}
+	}
+ out:
+	mutex_unlock(&ioc4_mutex);
+	return 0;
+}
+
+/* Unregister an IOC4 submodule */
+void
+ioc4_unregister_submodule(struct ioc4_submodule *is)
+{
+	struct ioc4_driver_data *idd;
+
+	mutex_lock(&ioc4_mutex);
+	list_del(&is->is_list);
+
+	/* Remove submodule for each IOC4 */
+	if (!is->is_remove)
+		goto out;
+
+	list_for_each_entry(idd, &ioc4_devices, idd_list) {
+		if (is->is_remove(idd)) {
+			printk(KERN_WARNING
+			       "%s: IOC4 submodule %s remove failed "
+			       "for pci_dev %s.\n",
+			       __FUNCTION__, module_name(is->is_owner),
+			       pci_name(idd->idd_pdev));
+		}
+	}
+ out:
+	mutex_unlock(&ioc4_mutex);
+}
+
+/*********************
+ * Device management *
+ *********************/
+
+#define IOC4_CALIBRATE_LOW_LIMIT \
+	(1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_LOW_MHZ)
+#define IOC4_CALIBRATE_HIGH_LIMIT \
+	(1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_HIGH_MHZ)
+#define IOC4_CALIBRATE_DEFAULT \
+	(1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_DEFAULT_MHZ)
+
+#define IOC4_CALIBRATE_END \
+	(IOC4_CALIBRATE_CYCLES + IOC4_CALIBRATE_DISCARD)
+
+#define IOC4_INT_OUT_MODE_TOGGLE 0x7	/* Toggle INT_OUT every COUNT+1 ticks */
+
+/* Determines external interrupt output clock period of the PCI bus an
+ * IOC4 is attached to.  This value can be used to determine the PCI
+ * bus speed.
+ *
+ * IOC4 has a design feature that various internal timers are derived from
+ * the PCI bus clock.  This causes IOC4 device drivers to need to take the
+ * bus speed into account when setting various register values (e.g. INT_OUT
+ * register COUNT field, UART divisors, etc).  Since this information is
+ * needed by several subdrivers, it is determined by the main IOC4 driver,
+ * even though the following code utilizes external interrupt registers
+ * to perform the speed calculation.
+ */
+static void
+ioc4_clock_calibrate(struct ioc4_driver_data *idd)
+{
+	union ioc4_int_out int_out;
+	union ioc4_gpcr gpcr;
+	unsigned int state, last_state = 1;
+	struct timespec start_ts, end_ts;
+	uint64_t start, end, period;
+	unsigned int count = 0;
+
+	/* Enable output */
+	gpcr.raw = 0;
+	gpcr.fields.dir = IOC4_GPCR_DIR_0;
+	gpcr.fields.int_out_en = 1;
+	writel(gpcr.raw, &idd->idd_misc_regs->gpcr_s.raw);
+
+	/* Reset to power-on state */
+	writel(0, &idd->idd_misc_regs->int_out.raw);
+	mmiowb();
+
+	/* Set up square wave */
+	int_out.raw = 0;
+	int_out.fields.count = IOC4_CALIBRATE_COUNT;
+	int_out.fields.mode = IOC4_INT_OUT_MODE_TOGGLE;
+	int_out.fields.diag = 0;
+	writel(int_out.raw, &idd->idd_misc_regs->int_out.raw);
+	mmiowb();
+
+	/* Check square wave period averaged over some number of cycles */
+	do {
+		int_out.raw = readl(&idd->idd_misc_regs->int_out.raw);
+		state = int_out.fields.int_out;
+		if (!last_state && state) {
+			count++;
+			if (count == IOC4_CALIBRATE_END) {
+				ktime_get_ts(&end_ts);
+				break;
+			} else if (count == IOC4_CALIBRATE_DISCARD)
+				ktime_get_ts(&start_ts);
+		}
+		last_state = state;
+	} while (1);
+
+	/* Calculation rearranged to preserve intermediate precision.
+	 * Logically:
+	 * 1. "end - start" gives us the measurement period over all
+	 *    the square wave cycles.
+	 * 2. Divide by number of square wave cycles to get the period
+	 *    of a square wave cycle.
+	 * 3. Divide by 2*(int_out.fields.count+1), which is the formula
+	 *    by which the IOC4 generates the square wave, to get the
+	 *    period of an IOC4 INT_OUT count.
+	 */
+	end = end_ts.tv_sec * NSEC_PER_SEC + end_ts.tv_nsec;
+	start = start_ts.tv_sec * NSEC_PER_SEC + start_ts.tv_nsec;
+	period = (end - start) /
+		(IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1));
+
+	/* Bounds check the result. */
+	if (period > IOC4_CALIBRATE_LOW_LIMIT ||
+	    period < IOC4_CALIBRATE_HIGH_LIMIT) {
+		printk(KERN_INFO
+		       "IOC4 %s: Clock calibration failed.  Assuming"
+		       "PCI clock is %d ns.\n",
+		       pci_name(idd->idd_pdev),
+		       IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR);
+		period = IOC4_CALIBRATE_DEFAULT;
+	} else {
+		u64 ns = period;
+
+		do_div(ns, IOC4_EXTINT_COUNT_DIVISOR);
+		printk(KERN_DEBUG
+		       "IOC4 %s: PCI clock is %lld ns.\n",
+		       pci_name(idd->idd_pdev), ns);
+	}
+
+	/* Remember results.  We store the extint clock period rather
+	 * than the PCI clock period so that greater precision is
+	 * retained.  Divide by IOC4_EXTINT_COUNT_DIVISOR to get
+	 * PCI clock period.
+	 */
+	idd->count_period = period;
+}
+
+/* There are three variants of IOC4 cards: IO9, IO10, and PCI-RT.
+ * Each brings out different combinations of IOC4 signals, thus.
+ * the IOC4 subdrivers need to know to which we're attached.
+ *
+ * We look for the presence of a SCSI (IO9) or SATA (IO10) controller
+ * on the same PCI bus at slot number 3 to differentiate IO9 from IO10.
+ * If neither is present, it's a PCI-RT.
+ */
+static unsigned int
+ioc4_variant(struct ioc4_driver_data *idd)
+{
+	struct pci_dev *pdev = NULL;
+	int found = 0;
+
+	/* IO9: Look for a QLogic ISP 12160 at the same bus and slot 3. */
+	do {
+		pdev = pci_get_device(PCI_VENDOR_ID_QLOGIC,
+				      PCI_DEVICE_ID_QLOGIC_ISP12160, pdev);
+		if (pdev &&
+		    idd->idd_pdev->bus->number == pdev->bus->number &&
+		    3 == PCI_SLOT(pdev->devfn))
+			found = 1;
+		pci_dev_put(pdev);
+	} while (pdev && !found);
+	if (NULL != pdev)
+		return IOC4_VARIANT_IO9;
+
+	/* IO10: Look for a Vitesse VSC 7174 at the same bus and slot 3. */
+	pdev = NULL;
+	do {
+		pdev = pci_get_device(PCI_VENDOR_ID_VITESSE,
+				      PCI_DEVICE_ID_VITESSE_VSC7174, pdev);
+		if (pdev &&
+		    idd->idd_pdev->bus->number == pdev->bus->number &&
+		    3 == PCI_SLOT(pdev->devfn))
+			found = 1;
+		pci_dev_put(pdev);
+	} while (pdev && !found);
+	if (NULL != pdev)
+		return IOC4_VARIANT_IO10;
+
+	/* PCI-RT: No SCSI/SATA controller will be present */
+	return IOC4_VARIANT_PCI_RT;
+}
+
+/* Adds a new instance of an IOC4 card */
+static int
+ioc4_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
+{
+	struct ioc4_driver_data *idd;
+	struct ioc4_submodule *is;
+	uint32_t pcmd;
+	int ret;
+
+	/* Enable IOC4 and take ownership of it */
+	if ((ret = pci_enable_device(pdev))) {
+		printk(KERN_WARNING
+		       "%s: Failed to enable IOC4 device for pci_dev %s.\n",
+		       __FUNCTION__, pci_name(pdev));
+		goto out;
+	}
+	pci_set_master(pdev);
+
+	/* Set up per-IOC4 data */
+	idd = kmalloc(sizeof(struct ioc4_driver_data), GFP_KERNEL);
+	if (!idd) {
+		printk(KERN_WARNING
+		       "%s: Failed to allocate IOC4 data for pci_dev %s.\n",
+		       __FUNCTION__, pci_name(pdev));
+		ret = -ENODEV;
+		goto out_idd;
+	}
+	idd->idd_pdev = pdev;
+	idd->idd_pci_id = pci_id;
+
+	/* Map IOC4 misc registers.  These are shared between subdevices
+	 * so the main IOC4 module manages them.
+	 */
+	idd->idd_bar0 = pci_resource_start(idd->idd_pdev, 0);
+	if (!idd->idd_bar0) {
+		printk(KERN_WARNING
+		       "%s: Unable to find IOC4 misc resource "
+		       "for pci_dev %s.\n",
+		       __FUNCTION__, pci_name(idd->idd_pdev));
+		ret = -ENODEV;
+		goto out_pci;
+	}
+	if (!request_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs),
+			    "ioc4_misc")) {
+		printk(KERN_WARNING
+		       "%s: Unable to request IOC4 misc region "
+		       "for pci_dev %s.\n",
+		       __FUNCTION__, pci_name(idd->idd_pdev));
+		ret = -ENODEV;
+		goto out_pci;
+	}
+	idd->idd_misc_regs = ioremap(idd->idd_bar0,
+				     sizeof(struct ioc4_misc_regs));
+	if (!idd->idd_misc_regs) {
+		printk(KERN_WARNING
+		       "%s: Unable to remap IOC4 misc region "
+		       "for pci_dev %s.\n",
+		       __FUNCTION__, pci_name(idd->idd_pdev));
+		ret = -ENODEV;
+		goto out_misc_region;
+	}
+
+	/* Failsafe portion of per-IOC4 initialization */
+
+	/* Detect card variant */
+	idd->idd_variant = ioc4_variant(idd);
+	printk(KERN_INFO "IOC4 %s: %s card detected.\n", pci_name(pdev),
+	       idd->idd_variant == IOC4_VARIANT_IO9 ? "IO9" :
+	       idd->idd_variant == IOC4_VARIANT_PCI_RT ? "PCI-RT" :
+	       idd->idd_variant == IOC4_VARIANT_IO10 ? "IO10" : "unknown");
+
+	/* Initialize IOC4 */
+	pci_read_config_dword(idd->idd_pdev, PCI_COMMAND, &pcmd);
+	pci_write_config_dword(idd->idd_pdev, PCI_COMMAND,
+			       pcmd | PCI_COMMAND_PARITY | PCI_COMMAND_SERR);
+
+	/* Determine PCI clock */
+	ioc4_clock_calibrate(idd);
+
+	/* Disable/clear all interrupts.  Need to do this here lest
+	 * one submodule request the shared IOC4 IRQ, but interrupt
+	 * is generated by a different subdevice.
+	 */
+	/* Disable */
+	writel(~0, &idd->idd_misc_regs->other_iec.raw);
+	writel(~0, &idd->idd_misc_regs->sio_iec);
+	/* Clear (i.e. acknowledge) */
+	writel(~0, &idd->idd_misc_regs->other_ir.raw);
+	writel(~0, &idd->idd_misc_regs->sio_ir);
+
+	/* Track PCI-device specific data */
+	idd->idd_serial_data = NULL;
+	pci_set_drvdata(idd->idd_pdev, idd);
+
+	mutex_lock(&ioc4_mutex);
+	list_add_tail(&idd->idd_list, &ioc4_devices);
+
+	/* Add this IOC4 to all submodules */
+	list_for_each_entry(is, &ioc4_submodules, is_list) {
+		if (is->is_probe && is->is_probe(idd)) {
+			printk(KERN_WARNING
+			       "%s: IOC4 submodule 0x%s probe failed "
+			       "for pci_dev %s.\n",
+			       __FUNCTION__, module_name(is->is_owner),
+			       pci_name(idd->idd_pdev));
+		}
+	}
+	mutex_unlock(&ioc4_mutex);
+
+	return 0;
+
+out_misc_region:
+	release_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
+out_pci:
+	kfree(idd);
+out_idd:
+	pci_disable_device(pdev);
+out:
+	return ret;
+}
+
+/* Removes a particular instance of an IOC4 card. */
+static void
+ioc4_remove(struct pci_dev *pdev)
+{
+	struct ioc4_submodule *is;
+	struct ioc4_driver_data *idd;
+
+	idd = pci_get_drvdata(pdev);
+
+	/* Remove this IOC4 from all submodules */
+	mutex_lock(&ioc4_mutex);
+	list_for_each_entry(is, &ioc4_submodules, is_list) {
+		if (is->is_remove && is->is_remove(idd)) {
+			printk(KERN_WARNING
+			       "%s: IOC4 submodule 0x%s remove failed "
+			       "for pci_dev %s.\n",
+			       __FUNCTION__, module_name(is->is_owner),
+			       pci_name(idd->idd_pdev));
+		}
+	}
+	mutex_unlock(&ioc4_mutex);
+
+	/* Release resources */
+	iounmap(idd->idd_misc_regs);
+	if (!idd->idd_bar0) {
+		printk(KERN_WARNING
+		       "%s: Unable to get IOC4 misc mapping for pci_dev %s. "
+		       "Device removal may be incomplete.\n",
+		       __FUNCTION__, pci_name(idd->idd_pdev));
+	}
+	release_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
+
+	/* Disable IOC4 and relinquish */
+	pci_disable_device(pdev);
+
+	/* Remove and free driver data */
+	mutex_lock(&ioc4_mutex);
+	list_del(&idd->idd_list);
+	mutex_unlock(&ioc4_mutex);
+	kfree(idd);
+}
+
+static struct pci_device_id ioc4_id_table[] = {
+	{PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
+	 PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
+	{0}
+};
+
+static struct pci_driver ioc4_driver = {
+	.name = "IOC4",
+	.id_table = ioc4_id_table,
+	.probe = ioc4_probe,
+	.remove = ioc4_remove,
+};
+
+MODULE_DEVICE_TABLE(pci, ioc4_id_table);
+
+/*********************
+ * Module management *
+ *********************/
+
+/* Module load */
+static int __devinit
+ioc4_init(void)
+{
+	return pci_register_driver(&ioc4_driver);
+}
+
+/* Module unload */
+static void __devexit
+ioc4_exit(void)
+{
+	pci_unregister_driver(&ioc4_driver);
+}
+
+module_init(ioc4_init);
+module_exit(ioc4_exit);
+
+MODULE_AUTHOR("Brent Casavant - Silicon Graphics, Inc. <bcasavan@sgi.com>");
+MODULE_DESCRIPTION("PCI driver master module for SGI IOC4 Base-IO Card");
+MODULE_LICENSE("GPL");
+
+EXPORT_SYMBOL(ioc4_register_submodule);
+EXPORT_SYMBOL(ioc4_unregister_submodule);