/* * 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 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/mmtimer.h> #include <linux/rtc.h> #include <linux/rwsem.h> #include <asm/sn/addrs.h> #include <asm/sn/clksupport.h> #include <asm/sn/shub_mmr.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 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 * *********************/ #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) { extern unsigned long sn_rtc_cycles_per_second; union ioc4_int_out int_out; union ioc4_gpcr gpcr; unsigned int state, last_state = 1; uint64_t start = 0, 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(); printk(KERN_INFO "%s: Calibrating PCI bus speed " "for pci_dev %s ... ", __FUNCTION__, pci_name(idd->idd_pdev)); /* 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) { end = rtc_time(); break; } else if (count == IOC4_CALIBRATE_DISCARD) start = rtc_time(); } last_state = state; } while (1); /* Calculation rearranged to preserve intermediate precision. * Logically: * 1. "end - start" gives us number of RTC cycles over all the * square wave cycles measured. * 2. Divide by number of square wave cycles to get number of * RTC cycles per 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 * number of RTC cycles per IOC4 INT_OUT count. * 4. Divide by sn_rtc_cycles_per_second to get seconds per * count. * 5. Multiply by 1E9 to get nanoseconds per count. */ period = ((end - start) * 1000000000) / (IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1) * sn_rtc_cycles_per_second); /* Bounds check the result. */ if (period > IOC4_CALIBRATE_LOW_LIMIT || period < IOC4_CALIBRATE_HIGH_LIMIT) { printk("failed. Assuming PCI clock ticks are %d ns.\n", IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR); period = IOC4_CALIBRATE_DEFAULT; } else { printk("succeeded. PCI clock ticks are %ld ns.\n", period / IOC4_EXTINT_COUNT_DIVISOR); } /* 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; } /* 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 */ /* 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); 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; } /* 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} }; static struct pci_driver __devinitdata 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);