[PATCH] ioc4: Core driver rewrite

This series of patches reworks the configuration and internal structure
of the SGI IOC4 I/O controller device drivers.

These changes are motivated by several factors:

- The IOC4 chip PCI resources are of mixed use between functions (i.e.
  multiple functions are handled in the same address range, sometimes
  within the same register), muddling resource ownership and initialization
  issues.  Centralizing this ownership in a core driver is desirable.

- The IOC4 chip implements multiple functions (serial, IDE, others not
  yet implemented in the mainline kernel) but is not a multifunction
  PCI device.  In order to properly handle device addition and removal
  as well as module insertion and deletion, an intermediary IOC4-specific
  driver layer is needed to handle these operations cleanly.

- All IOC4 drivers are currently enabled by a single CONFIG value.  As
  not all systems need all IOC4 functions, it is desireable to enable
  these drivers independently.

- The current IOC4 core driver will trigger loading of all function-level
  drivers, as it makes direct calls to them.  This situation should be
  reversed (i.e. function-level drivers cause loading of core driver)
  in order to maintain a clear and least-surprise driver loading model.

- IOC4 hardware design necessitates some driver-level dependency on
  the PCI bus clock speed.  Current code assumes a 66MHz bus, but the
  speed should be autodetected and appropriate compensation taken.

This patch series effects the above changes by a newly and better designed
IOC4 core driver with which the function-level drivers can register and
deregister themselves upon module insertion/removal.  By tracking these
modules, device addition/removal is also handled properly.  PCI resource
management and ownership issues are centralized in this core driver, and
IOC4-wide configuration actions such as bus speed detection are also
handled in this core driver.

This patch:

The SGI IOC4 I/O controller chip implements multiple functions, though it is
not a multi-function PCI device.  Additionally, various PCI resources of the
IOC4 are shared by multiple hardware functions, and thus resource ownership by
driver is not clearly delineated.  Due to the current driver design, all core
and subordinate drivers must be loaded, or none, which is undesirable if not
all IOC4 hardware features are being used.

This patch reorganizes the IOC4 drivers so that the core driver provides a
subdriver registration service.  Through appropriate callbacks the subdrivers
can now handle device addition and removal, as well as module insertion and
deletion (though the IOC4 IDE driver requires further work before module
deletion will work).  The core driver now takes care of allocating PCI
resources and data which must be shared between subdrivers, to clearly
delineate module ownership of these items.

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

1 files changed, 262 insertions, 28 deletions

diff --git a/drivers/sn/ioc4.c b/drivers/sn/ioc4.c
index d9e4ee280e5f..70862d72ea9d 100644
--- a/drivers/sn/ioc4.c
+++ b/drivers/sn/ioc4.c
@@ -6,60 +6,294 @@
  * Copyright (C) 2005 Silicon Graphics, Inc.  All Rights Reserved.
  */
 
-/*
- * This file contains a shim driver for the IOC4 IDE and serial drivers.
+/* 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_common.h>
-#include <linux/ide.h>
+#include <linux/ioc4.h>
+#include <linux/rwsem.h>
 
+/************************
+ * Submodule management *
+ ************************/
 
-static int __devinit
-ioc4_probe_one(struct pci_dev *pdev, const struct pci_device_id *pci_id)
+static LIST_HEAD(ioc4_devices);
+static DECLARE_RWSEM(ioc4_devices_rwsem);
+
+static LIST_HEAD(ioc4_submodules);
+static DECLARE_RWSEM(ioc4_submodules_rwsem);
+
+/* Register an IOC4 submodule */
+int
+ioc4_register_submodule(struct ioc4_submodule *is)
+{
+	struct ioc4_driver_data *idd;
+
+	down_write(&ioc4_submodules_rwsem);
+	list_add(&is->is_list, &ioc4_submodules);
+	up_write(&ioc4_submodules_rwsem);
+
+	/* Initialize submodule for each IOC4 */
+	if (!is->is_probe)
+		return 0;
+
+	down_read(&ioc4_devices_rwsem);
+	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));
+		}
+	}
+	up_read(&ioc4_devices_rwsem);
+
+	return 0;
+}
+
+/* Unregister an IOC4 submodule */
+void
+ioc4_unregister_submodule(struct ioc4_submodule *is)
 {
+	struct ioc4_driver_data *idd;
+
+	down_write(&ioc4_submodules_rwsem);
+	list_del(&is->is_list);
+	up_write(&ioc4_submodules_rwsem);
+
+	/* Remove submodule for each IOC4 */
+	if (!is->is_remove)
+		return;
+
+	down_read(&ioc4_devices_rwsem);
+	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));
+		}
+	}
+	up_read(&ioc4_devices_rwsem);
+}
+
+/*********************
+ * Device management *
+ *********************/
+
+/* 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 device with "
-				"pci_dev 0x%p... returning\n",
-				__FUNCTION__, (void *)pdev);
-		return ret;
+		       "%s: Failed to enable IOC4 device for pci_dev %s.\n",
+		       __FUNCTION__, pci_name(pdev));
+		goto out;
 	}
 	pci_set_master(pdev);
 
-	/* attach each sub-device */
-	ret = ioc4_ide_attach_one(pdev, pci_id);
-	if (ret)
-		return ret;
-	return ioc4_serial_attach_one(pdev, pci_id);
+	/* 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 */
+
+	/* 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);
+
+	/* 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);
+	down_write(&ioc4_devices_rwsem);
+	list_add(&idd->idd_list, &ioc4_devices);
+	up_write(&ioc4_devices_rwsem);
+
+	/* Add this IOC4 to all submodules */
+	down_read(&ioc4_submodules_rwsem);
+	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));
+		}
+	}
+	up_read(&ioc4_submodules_rwsem);
+
+	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;
 }
 
-/* pci device struct */
-static struct pci_device_id ioc4_s_id_table[] = {
+/* 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 */
+	down_read(&ioc4_submodules_rwsem);
+	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));
+		}
+	}
+	up_read(&ioc4_submodules_rwsem);
+
+	/* 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 */
+	down_write(&ioc4_devices_rwsem);
+	list_del(&idd->idd_list);
+	up_write(&ioc4_devices_rwsem);
+	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}
 };
-MODULE_DEVICE_TABLE(pci, ioc4_s_id_table);
 
-static struct pci_driver __devinitdata ioc4_s_driver = {
-	.name	= "IOC4",
-	.id_table = ioc4_s_id_table,
-	.probe	= ioc4_probe_one,
+static struct pci_driver __devinitdata ioc4_driver = {
+	.name = "IOC4",
+	.id_table = ioc4_id_table,
+	.probe = ioc4_probe,
+	.remove = ioc4_remove,
 };
 
-static int __devinit ioc4_detect(void)
+MODULE_DEVICE_TABLE(pci, ioc4_id_table);
+
+/*********************
+ * Module management *
+ *********************/
+
+/* Module load */
+static int __devinit
+ioc4_init(void)
 {
-	ioc4_serial_init();
+	return pci_register_driver(&ioc4_driver);
+}
 
-	return pci_register_driver(&ioc4_s_driver);
+/* Module unload */
+static void __devexit
+ioc4_exit(void)
+{
+	pci_unregister_driver(&ioc4_driver);
 }
-module_init(ioc4_detect);
 
-MODULE_AUTHOR("Pat Gefre - Silicon Graphics Inc. (SGI) <pfg@sgi.com>");
-MODULE_DESCRIPTION("PCI driver module for SGI IOC4 Base-IO Card");
+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);