616 lines
15 KiB
C
616 lines
15 KiB
C
/*
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* rar_register.c - An Intel Restricted Access Region register driver
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*
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* Copyright(c) 2009 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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*
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* -------------------------------------------------------------------
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* 20091204 Mark Allyn <mark.a.allyn@intel.com>
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* Ossama Othman <ossama.othman@intel.com>
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* Cleanup per feedback from Alan Cox and Arjan Van De Ven
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*
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* 20090806 Ossama Othman <ossama.othman@intel.com>
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* Return zero high address if upper 22 bits is zero.
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* Cleaned up checkpatch errors.
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* Clarified that driver is dealing with bus addresses.
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*
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* 20090702 Ossama Othman <ossama.othman@intel.com>
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* Removed unnecessary include directives
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* Cleaned up spinlocks.
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* Cleaned up logging.
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* Improved invalid parameter checks.
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* Fixed and simplified RAR address retrieval and RAR locking
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* code.
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*
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* 20090626 Mark Allyn <mark.a.allyn@intel.com>
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* Initial publish
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*/
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#define DEBUG 1
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#include "rar_register.h"
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/spinlock.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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/* === Lincroft Message Bus Interface === */
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/* Message Control Register */
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#define LNC_MCR_OFFSET 0xD0
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/* Maximum number of clients (other drivers using this driver) */
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#define MAX_RAR_CLIENTS 10
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/* Message Data Register */
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#define LNC_MDR_OFFSET 0xD4
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/* Message Opcodes */
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#define LNC_MESSAGE_READ_OPCODE 0xD0
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#define LNC_MESSAGE_WRITE_OPCODE 0xE0
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/* Message Write Byte Enables */
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#define LNC_MESSAGE_BYTE_WRITE_ENABLES 0xF
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/* B-unit Port */
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#define LNC_BUNIT_PORT 0x3
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/* === Lincroft B-Unit Registers - Programmed by IA32 firmware === */
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#define LNC_BRAR0L 0x10
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#define LNC_BRAR0H 0x11
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#define LNC_BRAR1L 0x12
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#define LNC_BRAR1H 0x13
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/* Reserved for SeP */
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#define LNC_BRAR2L 0x14
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#define LNC_BRAR2H 0x15
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/* Moorestown supports three restricted access regions. */
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#define MRST_NUM_RAR 3
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/* RAR Bus Address Range */
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struct RAR_address_range {
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dma_addr_t low;
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dma_addr_t high;
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};
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/* Structure containing low and high RAR register offsets. */
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struct RAR_offsets {
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u32 low; /* Register offset for low RAR bus address. */
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u32 high; /* Register offset for high RAR bus address. */
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};
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struct client {
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int (*client_callback)(void *client_data);
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void *customer_data;
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int client_called;
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};
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static DEFINE_MUTEX(rar_mutex);
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static DEFINE_MUTEX(lnc_reg_mutex);
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struct RAR_device {
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struct RAR_offsets const rar_offsets[MRST_NUM_RAR];
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struct RAR_address_range rar_addr[MRST_NUM_RAR];
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struct pci_dev *rar_dev;
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bool registered;
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};
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/* this platform has only one rar_device for 3 rar regions */
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static struct RAR_device my_rar_device = {
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.rar_offsets = {
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[0].low = LNC_BRAR0L,
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[0].high = LNC_BRAR0H,
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[1].low = LNC_BRAR1L,
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[1].high = LNC_BRAR1H,
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[2].low = LNC_BRAR2L,
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[2].high = LNC_BRAR2H
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}
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};
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/* this data is for handling requests from other drivers which arrive
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* prior to this driver initializing
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*/
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static struct client clients[MAX_RAR_CLIENTS];
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static int num_clients;
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/*
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* This function is used to retrieved RAR info using the Lincroft
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* message bus interface.
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*/
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static int retrieve_rar_addr(struct pci_dev *pdev,
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int offset,
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dma_addr_t *addr)
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{
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/*
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* ======== The Lincroft Message Bus Interface ========
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* Lincroft registers may be obtained from the PCI
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* (the Host Bridge) using the Lincroft Message Bus
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* Interface. That message bus interface is generally
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* comprised of two registers: a control register (MCR, 0xDO)
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* and a data register (MDR, 0xD4).
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*
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* The MCR (message control register) format is the following:
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* 1. [31:24]: Opcode
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* 2. [23:16]: Port
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* 3. [15:8]: Register Offset
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* 4. [7:4]: Byte Enables (use 0xF to set all of these bits
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* to 1)
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* 5. [3:0]: reserved
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*
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* Read (0xD0) and write (0xE0) opcodes are written to the
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* control register when reading and writing to Lincroft
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* registers, respectively.
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*
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* We're interested in registers found in the Lincroft
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* B-unit. The B-unit port is 0x3.
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*
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* The six B-unit RAR register offsets we use are listed
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* earlier in this file.
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*
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* Lastly writing to the MCR register requires the "Byte
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* enables" bits to be set to 1. This may be achieved by
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* writing 0xF at bit 4.
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*
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* The MDR (message data register) format is the following:
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* 1. [31:0]: Read/Write Data
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*
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* Data being read from this register is only available after
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* writing the appropriate control message to the MCR
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* register.
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*
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* Data being written to this register must be written before
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* writing the appropriate control message to the MCR
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* register.
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*/
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int result;
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/* Construct control message */
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u32 const message =
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(LNC_MESSAGE_READ_OPCODE << 24)
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| (LNC_BUNIT_PORT << 16)
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| (offset << 8)
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| (LNC_MESSAGE_BYTE_WRITE_ENABLES << 4);
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dev_dbg(&pdev->dev, "Offset for 'get' LNC MSG is %x\n", offset);
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if (addr == 0) {
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WARN_ON(1);
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return -EINVAL;
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}
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/*
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* We synchronize access to the Lincroft MCR and MDR registers
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* until BOTH the command is issued through the MCR register
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* and the corresponding data is read from the MDR register.
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* Otherwise a race condition would exist between accesses to
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* both registers.
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*/
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mutex_lock(&lnc_reg_mutex);
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/* Send the control message */
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result = pci_write_config_dword(pdev, LNC_MCR_OFFSET, message);
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dev_dbg(&pdev->dev, "Result from send ctl register is %x\n", result);
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if (!result) {
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result = pci_read_config_dword(pdev, LNC_MDR_OFFSET,
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(u32 *)addr);
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dev_dbg(&pdev->dev,
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"Result from read data register is %x\n", result);
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dev_dbg(&pdev->dev,
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"Value read from data register is %lx\n",
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(unsigned long)*addr);
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}
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mutex_unlock(&lnc_reg_mutex);
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return result;
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}
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static int set_rar_address(struct pci_dev *pdev,
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int offset,
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dma_addr_t addr)
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{
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/*
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* Data being written to this register must be written before
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* writing the appropriate control message to the MCR
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* register.
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* @note See rar_get_address() for a description of the
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* message bus interface being used here.
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*/
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int result = 0;
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/* Construct control message */
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u32 const message = (LNC_MESSAGE_WRITE_OPCODE << 24)
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| (LNC_BUNIT_PORT << 16)
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| (offset << 8)
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| (LNC_MESSAGE_BYTE_WRITE_ENABLES << 4);
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if (addr == 0) {
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WARN_ON(1);
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return -EINVAL;
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}
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dev_dbg(&pdev->dev, "Offset for 'set' LNC MSG is %x\n", offset);
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/*
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* We synchronize access to the Lincroft MCR and MDR registers
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* until BOTH the command is issued through the MCR register
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* and the corresponding data is read from the MDR register.
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* Otherwise a race condition would exist between accesses to
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* both registers.
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*/
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mutex_lock(&lnc_reg_mutex);
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/* Send the control message */
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result = pci_write_config_dword(pdev, LNC_MDR_OFFSET, addr);
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dev_dbg(&pdev->dev, "Result from write data register is %x\n", result);
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if (!result) {
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dev_dbg(&pdev->dev,
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"Value written to data register is %lx\n",
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(unsigned long)addr);
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result = pci_write_config_dword(pdev, LNC_MCR_OFFSET, message);
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dev_dbg(&pdev->dev, "Result from send ctl register is %x\n",
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result);
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}
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mutex_unlock(&lnc_reg_mutex);
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return result;
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}
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/*
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* Initialize RAR parameters, such as bus addresses, etc.
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*/
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static int init_rar_params(struct pci_dev *pdev)
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{
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unsigned int i;
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int result = 0;
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/* Retrieve RAR start and end bus addresses.
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* Access the RAR registers through the Lincroft Message Bus
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* Interface on PCI device: 00:00.0 Host bridge.
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*/
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for (i = 0; i < MRST_NUM_RAR; ++i) {
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struct RAR_offsets const *offset =
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&my_rar_device.rar_offsets[i];
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struct RAR_address_range *addr = &my_rar_device.rar_addr[i];
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if ((retrieve_rar_addr(pdev, offset->low, &addr->low) != 0)
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|| (retrieve_rar_addr(pdev, offset->high, &addr->high) != 0)) {
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result = -1;
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break;
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}
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/*
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* Only the upper 22 bits of the RAR addresses are
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* stored in their corresponding RAR registers so we
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* must set the lower 10 bits accordingly.
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* The low address has its lower 10 bits cleared, and
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* the high address has all its lower 10 bits set,
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* e.g.:
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* low = 0x2ffffc00
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*/
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addr->low &= (dma_addr_t)0xfffffc00u;
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/*
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* Set bits 9:0 on uppser address if bits 31:10 are non
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* zero; otherwize clear all bits
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*/
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if ((addr->high & 0xfffffc00u) == 0)
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addr->high = 0;
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else
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addr->high |= 0x3ffu;
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}
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/* Done accessing the device. */
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if (result == 0) {
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int z;
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for (z = 0; z != MRST_NUM_RAR; ++z) {
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/*
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* "BRAR" refers to the RAR registers in the
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* Lincroft B-unit.
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*/
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dev_info(&pdev->dev, "BRAR[%u] bus address range = "
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"[%lx, %lx]\n", z,
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(unsigned long)my_rar_device.rar_addr[z].low,
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(unsigned long)my_rar_device.rar_addr[z].high);
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}
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}
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return result;
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}
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/*
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* The rar_get_address function is used by other device drivers
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* to obtain RAR address information on a RAR. It takes three
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* parameters:
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*
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* int rar_index
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* The rar_index is an index to the rar for which you wish to retrieve
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* the address information.
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* Values can be 0,1, or 2.
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*
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* The function returns a 0 upon success or a -1 if there is no RAR
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* facility on this system.
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*/
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int rar_get_address(int rar_index,
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dma_addr_t *start_address,
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dma_addr_t *end_address)
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{
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int result = -ENODEV;
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if (my_rar_device.registered) {
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if (start_address == 0 || end_address == 0
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|| rar_index >= MRST_NUM_RAR || rar_index < 0) {
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result = -EINVAL;
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} else {
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*start_address =
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my_rar_device.rar_addr[rar_index].low;
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*end_address =
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my_rar_device.rar_addr[rar_index].high;
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result = 0;
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}
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}
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return result;
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}
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EXPORT_SYMBOL(rar_get_address);
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/*
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* The rar_lock function is ued by other device drivers to lock an RAR.
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* once an RAR is locked, it stays locked until the next system reboot.
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* The function takes one parameter:
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*
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* int rar_index
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* The rar_index is an index to the rar that you want to lock.
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* Values can be 0,1, or 2.
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*
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* The function returns a 0 upon success or a -1 if there is no RAR
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* facility on this system.
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*/
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int rar_lock(int rar_index)
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{
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int result = -ENODEV;
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if (rar_index >= MRST_NUM_RAR || rar_index < 0) {
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result = -EINVAL;
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return result;
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}
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dev_dbg(&my_rar_device.rar_dev->dev, "rar_lock mutex locking\n");
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mutex_lock(&rar_mutex);
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if (my_rar_device.registered) {
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dma_addr_t low = my_rar_device.rar_addr[rar_index].low &
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0xfffffc00u;
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dma_addr_t high = my_rar_device.rar_addr[rar_index].high &
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0xfffffc00u;
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/*
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* Only allow I/O from the graphics and Langwell;
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* Not from the x96 processor
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*/
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if (rar_index == (int)RAR_TYPE_VIDEO) {
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low |= 0x00000009;
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high |= 0x00000015;
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}
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else if (rar_index == (int)RAR_TYPE_AUDIO) {
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/* Only allow I/O from Langwell; nothing from x86 */
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low |= 0x00000008;
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high |= 0x00000018;
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}
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else
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/* Read-only from all agents */
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high |= 0x00000018;
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/*
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* Now program the register using the Lincroft message
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* bus interface.
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*/
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result = set_rar_address(my_rar_device.rar_dev,
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my_rar_device.rar_offsets[rar_index].low,
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low);
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if (result == 0)
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result = set_rar_address(
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my_rar_device.rar_dev,
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my_rar_device.rar_offsets[rar_index].high,
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high);
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}
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dev_dbg(&my_rar_device.rar_dev->dev, "rar_lock mutex unlocking\n");
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mutex_unlock(&rar_mutex);
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return result;
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}
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EXPORT_SYMBOL(rar_lock);
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/* The register_rar function is to used by other device drivers
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* to ensure that this driver is ready. As we cannot be sure of
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* the compile/execute order of dirvers in ther kernel, it is
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* best to give this driver a callback function to call when
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* it is ready to give out addresses. The callback function
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* would have those steps that continue the initialization of
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* a driver that do require a valid RAR address. One of those
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* steps would be to call rar_get_address()
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* This function return 0 on success an -1 on failure.
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*/
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int register_rar(int (*callback)(void *yourparameter), void *yourparameter)
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{
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int result = -ENODEV;
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if (callback == NULL)
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return -EINVAL;
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mutex_lock(&rar_mutex);
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if (my_rar_device.registered) {
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mutex_unlock(&rar_mutex);
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/*
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* if the driver already registered, then we can simply
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* call the callback right now
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*/
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return (*callback)(yourparameter);
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}
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if (num_clients < MRST_NUM_RAR) {
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clients[num_clients].client_callback = callback;
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clients[num_clients].customer_data = yourparameter;
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num_clients += 1;
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result = 0;
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}
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mutex_unlock(&rar_mutex);
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return result;
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}
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EXPORT_SYMBOL(register_rar);
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/* Suspend - returns -ENOSYS */
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static int rar_suspend(struct pci_dev *dev, pm_message_t state)
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{
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return -ENOSYS;
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}
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static int rar_resume(struct pci_dev *dev)
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{
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return -ENOSYS;
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}
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/*
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* This function registers the driver with the device subsystem (
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* either PCI, USB, etc).
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* Function that is activaed on the succesful probe of the RAR device
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* (Moorestown host controller).
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*/
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static int rar_probe(struct pci_dev *dev, const struct pci_device_id *id)
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{
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int error;
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int counter;
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dev_dbg(&dev->dev, "PCI probe starting\n");
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/* enable the device */
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error = pci_enable_device(dev);
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if (error) {
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dev_err(&dev->dev,
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"Error enabling RAR register PCI device\n");
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goto end_function;
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}
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/* we have only one device; fill in the rar_device structure */
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my_rar_device.rar_dev = dev;
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/*
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* Initialize the RAR parameters, which have to be retrieved
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* via the message bus interface.
|
|
*/
|
|
error = init_rar_params(dev);
|
|
if (error) {
|
|
pci_disable_device(dev);
|
|
|
|
dev_err(&dev->dev,
|
|
"Error retrieving RAR addresses\n");
|
|
|
|
goto end_function;
|
|
}
|
|
|
|
dev_dbg(&dev->dev, "PCI probe locking\n");
|
|
mutex_lock(&rar_mutex);
|
|
my_rar_device.registered = 1;
|
|
|
|
/* now call anyone who has registered (using callbacks) */
|
|
for (counter = 0; counter < num_clients; counter += 1) {
|
|
if (clients[counter].client_callback) {
|
|
error = (*clients[counter].client_callback)(
|
|
clients[counter].customer_data);
|
|
/* set callback to NULL to indicate it has been done */
|
|
clients[counter].client_callback = NULL;
|
|
dev_dbg(&my_rar_device.rar_dev->dev,
|
|
"Callback called for %d\n",
|
|
counter);
|
|
}
|
|
}
|
|
|
|
dev_dbg(&dev->dev, "PCI probe unlocking\n");
|
|
mutex_unlock(&rar_mutex);
|
|
|
|
end_function:
|
|
|
|
return error;
|
|
}
|
|
|
|
const struct pci_device_id rar_pci_id_tbl[] = {
|
|
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_RAR_DEVICE_ID) },
|
|
{ 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,
|
|
.suspend = rar_suspend,
|
|
.resume = rar_resume
|
|
};
|
|
|
|
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");
|