diff options
Diffstat (limited to 'drivers/platform/x86/intel_rar_register.c')
| -rw-r--r-- | drivers/platform/x86/intel_rar_register.c | 671 |
1 files changed, 671 insertions, 0 deletions
diff --git a/drivers/platform/x86/intel_rar_register.c b/drivers/platform/x86/intel_rar_register.c new file mode 100644 index 000000000000..73f8e6d72669 --- /dev/null +++ b/drivers/platform/x86/intel_rar_register.c @@ -0,0 +1,671 @@ +/* + * rar_register.c - An Intel Restricted Access Region register driver + * + * Copyright(c) 2009 Intel Corporation. All rights reserved. + * + * 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., 59 Temple Place - Suite 330, Boston, MA + * 02111-1307, USA. + * + * ------------------------------------------------------------------- + * 20091204 Mark Allyn <mark.a.allyn@intel.com> + * Ossama Othman <ossama.othman@intel.com> + * Cleanup per feedback from Alan Cox and Arjan Van De Ven + * + * 20090806 Ossama Othman <ossama.othman@intel.com> + * Return zero high address if upper 22 bits is zero. + * Cleaned up checkpatch errors. + * Clarified that driver is dealing with bus addresses. + * + * 20090702 Ossama Othman <ossama.othman@intel.com> + * Removed unnecessary include directives + * Cleaned up spinlocks. + * Cleaned up logging. + * Improved invalid parameter checks. + * Fixed and simplified RAR address retrieval and RAR locking + * code. + * + * 20090626 Mark Allyn <mark.a.allyn@intel.com> + * Initial publish + */ + +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/spinlock.h> +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/rar_register.h> + +/* === Lincroft Message Bus Interface === */ +#define LNC_MCR_OFFSET 0xD0 /* Message Control Register */ +#define LNC_MDR_OFFSET 0xD4 /* Message Data Register */ + +/* Message Opcodes */ +#define LNC_MESSAGE_READ_OPCODE 0xD0 +#define LNC_MESSAGE_WRITE_OPCODE 0xE0 + +/* Message Write Byte Enables */ +#define LNC_MESSAGE_BYTE_WRITE_ENABLES 0xF + +/* B-unit Port */ +#define LNC_BUNIT_PORT 0x3 + +/* === Lincroft B-Unit Registers - Programmed by IA32 firmware === */ +#define LNC_BRAR0L 0x10 +#define LNC_BRAR0H 0x11 +#define LNC_BRAR1L 0x12 +#define LNC_BRAR1H 0x13 +/* Reserved for SeP */ +#define LNC_BRAR2L 0x14 +#define LNC_BRAR2H 0x15 + +/* Moorestown supports three restricted access regions. */ +#define MRST_NUM_RAR 3 + +/* RAR Bus Address Range */ +struct rar_addr { + dma_addr_t low; + dma_addr_t high; +}; + +/* + * We create one of these for each RAR + */ +struct client { + int (*callback)(unsigned long data); + unsigned long driver_priv; + bool busy; +}; + +static DEFINE_MUTEX(rar_mutex); +static DEFINE_MUTEX(lnc_reg_mutex); + +/* + * One per RAR device (currently only one device) + */ +struct rar_device { + struct rar_addr rar_addr[MRST_NUM_RAR]; + struct pci_dev *rar_dev; + bool registered; + bool allocated; + struct client client[MRST_NUM_RAR]; +}; + +/* Current platforms have only one rar_device for 3 rar regions */ +static struct rar_device my_rar_device; + +/* + * Abstract out multiple device support. Current platforms only + * have a single RAR device. + */ + +/** + * alloc_rar_device - return a new RAR structure + * + * Return a new (but not yet ready) RAR device object + */ +static struct rar_device *alloc_rar_device(void) +{ + if (my_rar_device.allocated) + return NULL; + my_rar_device.allocated = 1; + return &my_rar_device; +} + +/** + * free_rar_device - free a RAR object + * @rar: the RAR device being freed + * + * Release a RAR object and any attached resources + */ +static void free_rar_device(struct rar_device *rar) +{ + pci_dev_put(rar->rar_dev); + rar->allocated = 0; +} + +/** + * _rar_to_device - return the device handling this RAR + * @rar: RAR number + * @off: returned offset + * + * Internal helper for looking up RAR devices. This and alloc are the + * two functions that need touching to go to multiple RAR devices. + */ +static struct rar_device *_rar_to_device(int rar, int *off) +{ + if (rar >= 0 && rar <= 3) { + *off = rar; + return &my_rar_device; + } + return NULL; +} + +/** + * rar_to_device - return the device handling this RAR + * @rar: RAR number + * @off: returned offset + * + * Return the device this RAR maps to if one is present, otherwise + * returns NULL. Reports the offset relative to the base of this + * RAR device in off. + */ +static struct rar_device *rar_to_device(int rar, int *off) +{ + struct rar_device *rar_dev = _rar_to_device(rar, off); + if (rar_dev == NULL || !rar_dev->registered) + return NULL; + return rar_dev; +} + +/** + * rar_to_client - return the client handling this RAR + * @rar: RAR number + * + * Return the client this RAR maps to if a mapping is known, otherwise + * returns NULL. + */ +static struct client *rar_to_client(int rar) +{ + int idx; + struct rar_device *r = _rar_to_device(rar, &idx); + if (r != NULL) + return &r->client[idx]; + return NULL; +} + +/** + * rar_read_addr - retrieve a RAR mapping + * @pdev: PCI device for the RAR + * @offset: offset for message + * @addr: returned address + * + * Reads the address of a given RAR register. Returns 0 on success + * or an error code on failure. + */ +static int rar_read_addr(struct pci_dev *pdev, int offset, dma_addr_t *addr) +{ + /* + * ======== The Lincroft Message Bus Interface ======== + * Lincroft registers may be obtained via PCI from + * the host bridge using the Lincroft Message Bus + * Interface. That message bus interface is generally + * comprised of two registers: a control register (MCR, 0xDO) + * and a data register (MDR, 0xD4). + * + * The MCR (message control register) format is the following: + * 1. [31:24]: Opcode + * 2. [23:16]: Port + * 3. [15:8]: Register Offset + * 4. [7:4]: Byte Enables (use 0xF to set all of these bits + * to 1) + * 5. [3:0]: reserved + * + * Read (0xD0) and write (0xE0) opcodes are written to the + * control register when reading and writing to Lincroft + * registers, respectively. + * + * We're interested in registers found in the Lincroft + * B-unit. The B-unit port is 0x3. + * + * The six B-unit RAR register offsets we use are listed + * earlier in this file. + * + * Lastly writing to the MCR register requires the "Byte + * enables" bits to be set to 1. This may be achieved by + * writing 0xF at bit 4. + * + * The MDR (message data register) format is the following: + * 1. [31:0]: Read/Write Data + * + * Data being read from this register is only available after + * writing the appropriate control message to the MCR + * register. + * + * Data being written to this register must be written before + * writing the appropriate control message to the MCR + * register. + */ + + int result; + u32 addr32; + + /* Construct control message */ + u32 const message = + (LNC_MESSAGE_READ_OPCODE << 24) + | (LNC_BUNIT_PORT << 16) + | (offset << 8) + | (LNC_MESSAGE_BYTE_WRITE_ENABLES << 4); + + dev_dbg(&pdev->dev, "Offset for 'get' LNC MSG is %x\n", offset); + + /* + * We synchronize access to the Lincroft MCR and MDR registers + * until BOTH the command is issued through the MCR register + * and the corresponding data is read from the MDR register. + * Otherwise a race condition would exist between accesses to + * both registers. + */ + + mutex_lock(&lnc_reg_mutex); + + /* Send the control message */ + result = pci_write_config_dword(pdev, LNC_MCR_OFFSET, message); + if (!result) { + /* Read back the address as a 32bit value */ + result = pci_read_config_dword(pdev, LNC_MDR_OFFSET, &addr32); + *addr = (dma_addr_t)addr32; + } + mutex_unlock(&lnc_reg_mutex); + return result; +} + +/** + * rar_set_addr - Set a RAR mapping + * @pdev: PCI device for the RAR + * @offset: offset for message + * @addr: address to set + * + * Sets the address of a given RAR register. Returns 0 on success + * or an error code on failure. + */ +static int rar_set_addr(struct pci_dev *pdev, + int offset, + dma_addr_t addr) +{ + /* + * Data being written to this register must be written before + * writing the appropriate control message to the MCR + * register. + * See rar_get_addrs() for a description of the + * message bus interface being used here. + */ + + int result; + + /* Construct control message */ + u32 const message = (LNC_MESSAGE_WRITE_OPCODE << 24) + | (LNC_BUNIT_PORT << 16) + | (offset << 8) + | (LNC_MESSAGE_BYTE_WRITE_ENABLES << 4); + + /* + * We synchronize access to the Lincroft MCR and MDR registers + * until BOTH the command is issued through the MCR register + * and the corresponding data is read from the MDR register. + * Otherwise a race condition would exist between accesses to + * both registers. + */ + + mutex_lock(&lnc_reg_mutex); + + /* Send the control message */ + result = pci_write_config_dword(pdev, LNC_MDR_OFFSET, addr); + if (!result) + /* And address */ + result = pci_write_config_dword(pdev, LNC_MCR_OFFSET, message); + + mutex_unlock(&lnc_reg_mutex); + return result; +} + +/* + * rar_init_params - Initialize RAR parameters + * @rar: RAR device to initialise + * + * Initialize RAR parameters, such as bus addresses, etc. Returns 0 + * on success, or an error code on failure. + */ +static int init_rar_params(struct rar_device *rar) +{ + struct pci_dev *pdev = rar->rar_dev; + unsigned int i; + int result = 0; + int offset = 0x10; /* RAR 0 to 2 in order low/high/low/high/... */ + + /* Retrieve RAR start and end bus addresses. + * Access the RAR registers through the Lincroft Message Bus + * Interface on PCI device: 00:00.0 Host bridge. + */ + + for (i = 0; i < MRST_NUM_RAR; ++i) { + struct rar_addr *addr = &rar->rar_addr[i]; + + result = rar_read_addr(pdev, offset++, &addr->low); + if (result != 0) + return result; + + result = rar_read_addr(pdev, offset++, &addr->high); + if (result != 0) + return result; + + + /* + * Only the upper 22 bits of the RAR addresses are + * stored in their corresponding RAR registers so we + * must set the lower 10 bits accordingly. + + * The low address has its lower 10 bits cleared, and + * the high address has all its lower 10 bits set, + * e.g.: + * low = 0x2ffffc00 + */ + + addr->low &= (dma_addr_t)0xfffffc00u; + + /* + * Set bits 9:0 on uppser address if bits 31:10 are non + * zero; otherwize clear all bits + */ + + if ((addr->high & 0xfffffc00u) == 0) + addr->high = 0; + else + addr->high |= 0x3ffu; + } + /* Done accessing the device. */ + + if (result == 0) { + for (i = 0; i != MRST_NUM_RAR; ++i) { + /* + * "BRAR" refers to the RAR registers in the + * Lincroft B-unit. + */ + dev_info(&pdev->dev, "BRAR[%u] bus address range = " + "[%lx, %lx]\n", i, + (unsigned long)rar->rar_addr[i].low, + (unsigned long)rar->rar_addr[i].high); + } + } + return result; +} + +/** + * rar_get_address - get the bus address in a RAR + * @start: return value of start address of block + * @end: return value of end address of block + * + * The rar_get_address function is used by other device drivers + * to obtain RAR address information on a RAR. It takes three + * parameters: + * + * The function returns a 0 upon success or an error if there is no RAR + * facility on this system. + */ +int rar_get_address(int rar_index, dma_addr_t *start, dma_addr_t *end) +{ + int idx; + struct rar_device *rar = rar_to_device(rar_index, &idx); + + if (rar == NULL) { + WARN_ON(1); + return -ENODEV; + } + + *start = rar->rar_addr[idx].low; + *end = rar->rar_addr[idx].high; + return 0; +} +EXPORT_SYMBOL(rar_get_address); + +/** + * rar_lock - lock a RAR register + * @rar_index: RAR to lock (0-2) + * + * The rar_lock function is ued by other device drivers to lock an RAR. + * once a RAR is locked, it stays locked until the next system reboot. + * + * The function returns a 0 upon success or an error if there is no RAR + * facility on this system, or the locking fails + */ +int rar_lock(int rar_index) +{ + struct rar_device *rar; + int result; + int idx; + dma_addr_t low, high; + + rar = rar_to_device(rar_index, &idx); + + if (rar == NULL) { + WARN_ON(1); + return -EINVAL; + } + + low = rar->rar_addr[idx].low & 0xfffffc00u; + high = rar->rar_addr[idx].high & 0xfffffc00u; + + /* + * Only allow I/O from the graphics and Langwell; + * not from the x86 processor + */ + + if (rar_index == RAR_TYPE_VIDEO) { + low |= 0x00000009; + high |= 0x00000015; + } else if (rar_index == RAR_TYPE_AUDIO) { + /* Only allow I/O from Langwell; nothing from x86 */ + low |= 0x00000008; + high |= 0x00000018; + } else + /* Read-only from all agents */ + high |= 0x00000018; + + /* + * Now program the register using the Lincroft message + * bus interface. + */ + result = rar_set_addr(rar->rar_dev, + 2 * idx, low); + + if (result == 0) + result = rar_set_addr(rar->rar_dev, + 2 * idx + 1, high); + + return result; +} +EXPORT_SYMBOL(rar_lock); + +/** + * register_rar - register a RAR handler + * @num: RAR we wish to register for + * @callback: function to call when RAR support is available + * @data: data to pass to this function + * + * The register_rar function is to used by other device drivers + * to ensure that this driver is ready. As we cannot be sure of + * the compile/execute order of drivers in ther kernel, it is + * best to give this driver a callback function to call when + * it is ready to give out addresses. The callback function + * would have those steps that continue the initialization of + * a driver that do require a valid RAR address. One of those + * steps would be to call rar_get_address() + * + * This function return 0 on success or an error code on failure. + */ +int register_rar(int num, int (*callback)(unsigned long data), + unsigned long data) +{ + /* For now we hardcode a single RAR device */ + struct rar_device *rar; + struct client *c; + int idx; + int retval = 0; + + mutex_lock(&rar_mutex); + + /* Do we have a client mapping for this RAR number ? */ + c = rar_to_client(num); + if (c == NULL) { + retval = -ERANGE; + goto done; + } + /* Is it claimed ? */ + if (c->busy) { + retval = -EBUSY; + goto done; + } + c->busy = 1; + + /* See if we have a handler for this RAR yet, if we do then fire it */ + rar = rar_to_device(num, &idx); + + if (rar) { + /* + * if the driver already registered, then we can simply + * call the callback right now + */ + (*callback)(data); + goto done; + } + + /* Arrange to be called back when the hardware is found */ + c->callback = callback; + c->driver_priv = data; +done: + mutex_unlock(&rar_mutex); + return retval; +} +EXPORT_SYMBOL(register_rar); + +/** + * unregister_rar - release a RAR allocation + * @num: RAR number + * + * Releases a RAR allocation, or pending allocation. If a callback is + * pending then this function will either complete before the unregister + * returns or not at all. + */ + +void unregister_rar(int num) +{ + struct client *c; + + mutex_lock(&rar_mutex); + c = rar_to_client(num); + if (c == NULL || !c->busy) + WARN_ON(1); + else + c->busy = 0; + mutex_unlock(&rar_mutex); +} +EXPORT_SYMBOL(unregister_rar); + +/** + * rar_callback - Process callbacks + * @rar: new RAR device + * + * Process the callbacks for a newly found RAR device. + */ + +static void rar_callback(struct rar_device *rar) +{ + struct client *c = &rar->client[0]; + int i; + + mutex_lock(&rar_mutex); + + rar->registered = 1; /* Ensure no more callbacks queue */ + + for (i = 0; i < MRST_NUM_RAR; i++) { + if (c->callback && c->busy) { + c->callback(c->driver_priv); + c->callback = NULL; + } + c++; + } + mutex_unlock(&rar_mutex); +} + +/** + * rar_probe - PCI probe callback + * @dev: PCI device + * @id: matching entry in the match table + * + * A RAR device has been discovered. Initialise it and if successful + * process any pending callbacks that can now be completed. + */ +static int rar_probe(struct pci_dev *dev, const struct pci_device_id *id) +{ + int error; + struct rar_device *rar; + + dev_dbg(&dev->dev, "PCI probe starting\n"); + + rar = alloc_rar_device(); + if (rar == NULL) + return -EBUSY; + + /* Enable the device */ + error = pci_enable_device(dev); + if (error) { + dev_err(&dev->dev, + "Error enabling RAR register PCI device\n"); + goto end_function; + } + + /* Fill in the rar_device structure */ + rar->rar_dev = pci_dev_get(dev); + pci_set_drvdata(dev, rar); + + /* + * Initialize the RAR parameters, which have to be retrieved + * via the message bus interface. + */ + error = init_rar_params(rar); + if (error) { + pci_disable_device(dev); + dev_err(&dev->dev, "Error retrieving RAR addresses\n"); + goto end_function; + } + /* now call anyone who has registered (using callbacks) */ + rar_callback(rar); + return 0; +end_function: + free_rar_device(rar); + return error; +} + +const struct pci_device_id rar_pci_id_tbl[] = { + { PCI_VDEVICE(INTEL, 0x4110) }, + { 0 } +}; + +MODULE_DEVICE_TABLE(pci, rar_pci_id_tbl); + +const struct pci_device_id *my_id_table = rar_pci_id_tbl; + +/* field for registering driver to PCI device */ +static struct pci_driver rar_pci_driver = { + .name = "rar_register_driver", + .id_table = rar_pci_id_tbl, + .probe = rar_probe, + /* Cannot be unplugged - no remove */ +}; + +static int __init rar_init_handler(void) +{ + return pci_register_driver(&rar_pci_driver); +} + +static void __exit rar_exit_handler(void) +{ + pci_unregister_driver(&rar_pci_driver); +} + +module_init(rar_init_handler); +module_exit(rar_exit_handler); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Intel Restricted Access Region Register Driver"); |