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0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003     Copyright (c) 1998 - 2002  Frodo Looijaard <frodol@dds.nl>,
0004     Philip Edelbrock <phil@netroedge.com>, Kyösti Mälkki <kmalkki@cc.hut.fi>,
0005     Mark D. Studebaker <mdsxyz123@yahoo.com>
0006     Copyright (C) 2005 - 2008  Jean Delvare <jdelvare@suse.de>
0007 
0008 */
0009 
0010 /*
0011    Supports the following VIA south bridges:
0012 
0013    Chip name          PCI ID  REV     I2C block
0014    VT82C596A          0x3050             no
0015    VT82C596B          0x3051             no
0016    VT82C686A          0x3057  0x30       no
0017    VT82C686B          0x3057  0x40       yes
0018    VT8231             0x8235             no?
0019    VT8233             0x3074             yes
0020    VT8233A            0x3147             yes?
0021    VT8235             0x3177             yes
0022    VT8237R            0x3227             yes
0023    VT8237A            0x3337             yes
0024    VT8237S            0x3372             yes
0025    VT8251             0x3287             yes
0026    CX700              0x8324             yes
0027    VX800/VX820        0x8353             yes
0028    VX855/VX875        0x8409             yes
0029 
0030    Note: we assume there can only be one device, with one SMBus interface.
0031 */
0032 
0033 #include <linux/module.h>
0034 #include <linux/delay.h>
0035 #include <linux/pci.h>
0036 #include <linux/kernel.h>
0037 #include <linux/stddef.h>
0038 #include <linux/ioport.h>
0039 #include <linux/i2c.h>
0040 #include <linux/init.h>
0041 #include <linux/acpi.h>
0042 #include <linux/io.h>
0043 
0044 static struct pci_dev *vt596_pdev;
0045 
0046 #define SMBBA1      0x90
0047 #define SMBBA2      0x80
0048 #define SMBBA3      0xD0
0049 
0050 /* SMBus address offsets */
0051 static unsigned short vt596_smba;
0052 #define SMBHSTSTS   (vt596_smba + 0)
0053 #define SMBHSTCNT   (vt596_smba + 2)
0054 #define SMBHSTCMD   (vt596_smba + 3)
0055 #define SMBHSTADD   (vt596_smba + 4)
0056 #define SMBHSTDAT0  (vt596_smba + 5)
0057 #define SMBHSTDAT1  (vt596_smba + 6)
0058 #define SMBBLKDAT   (vt596_smba + 7)
0059 
0060 /* PCI Address Constants */
0061 
0062 /* SMBus data in configuration space can be found in two places,
0063    We try to select the better one */
0064 
0065 static unsigned short SMBHSTCFG = 0xD2;
0066 
0067 /* Other settings */
0068 #define MAX_TIMEOUT 500
0069 
0070 /* VT82C596 constants */
0071 #define VT596_QUICK     0x00
0072 #define VT596_BYTE      0x04
0073 #define VT596_BYTE_DATA     0x08
0074 #define VT596_WORD_DATA     0x0C
0075 #define VT596_PROC_CALL     0x10
0076 #define VT596_BLOCK_DATA    0x14
0077 #define VT596_I2C_BLOCK_DATA    0x34
0078 
0079 
0080 /* If force is set to anything different from 0, we forcibly enable the
0081    VT596. DANGEROUS! */
0082 static bool force;
0083 module_param(force, bool, 0);
0084 MODULE_PARM_DESC(force, "Forcibly enable the SMBus. DANGEROUS!");
0085 
0086 /* If force_addr is set to anything different from 0, we forcibly enable
0087    the VT596 at the given address. VERY DANGEROUS! */
0088 static u16 force_addr;
0089 module_param_hw(force_addr, ushort, ioport, 0);
0090 MODULE_PARM_DESC(force_addr,
0091          "Forcibly enable the SMBus at the given address. "
0092          "EXTREMELY DANGEROUS!");
0093 
0094 
0095 static struct pci_driver vt596_driver;
0096 static struct i2c_adapter vt596_adapter;
0097 
0098 #define FEATURE_I2CBLOCK    (1<<0)
0099 static unsigned int vt596_features;
0100 
0101 #ifdef DEBUG
0102 static void vt596_dump_regs(const char *msg, u8 size)
0103 {
0104     dev_dbg(&vt596_adapter.dev, "%s: STS=%02x CNT=%02x CMD=%02x ADD=%02x "
0105         "DAT=%02x,%02x\n", msg, inb_p(SMBHSTSTS), inb_p(SMBHSTCNT),
0106         inb_p(SMBHSTCMD), inb_p(SMBHSTADD), inb_p(SMBHSTDAT0),
0107         inb_p(SMBHSTDAT1));
0108 
0109     if (size == VT596_BLOCK_DATA
0110      || size == VT596_I2C_BLOCK_DATA) {
0111         int i;
0112 
0113         dev_dbg(&vt596_adapter.dev, "BLK=");
0114         for (i = 0; i < I2C_SMBUS_BLOCK_MAX / 2; i++)
0115             printk("%02x,", inb_p(SMBBLKDAT));
0116         printk("\n");
0117         dev_dbg(&vt596_adapter.dev, "    ");
0118         for (; i < I2C_SMBUS_BLOCK_MAX - 1; i++)
0119             printk("%02x,", inb_p(SMBBLKDAT));
0120         printk("%02x\n", inb_p(SMBBLKDAT));
0121     }
0122 }
0123 #else
0124 static inline void vt596_dump_regs(const char *msg, u8 size) { }
0125 #endif
0126 
0127 /* Return -1 on error, 0 on success */
0128 static int vt596_transaction(u8 size)
0129 {
0130     int temp;
0131     int result = 0;
0132     int timeout = 0;
0133 
0134     vt596_dump_regs("Transaction (pre)", size);
0135 
0136     /* Make sure the SMBus host is ready to start transmitting */
0137     if ((temp = inb_p(SMBHSTSTS)) & 0x1F) {
0138         dev_dbg(&vt596_adapter.dev, "SMBus busy (0x%02x). "
0139             "Resetting...\n", temp);
0140 
0141         outb_p(temp, SMBHSTSTS);
0142         if ((temp = inb_p(SMBHSTSTS)) & 0x1F) {
0143             dev_err(&vt596_adapter.dev, "SMBus reset failed! "
0144                 "(0x%02x)\n", temp);
0145             return -EBUSY;
0146         }
0147     }
0148 
0149     /* Start the transaction by setting bit 6 */
0150     outb_p(0x40 | size, SMBHSTCNT);
0151 
0152     /* We will always wait for a fraction of a second */
0153     do {
0154         msleep(1);
0155         temp = inb_p(SMBHSTSTS);
0156     } while ((temp & 0x01) && (++timeout < MAX_TIMEOUT));
0157 
0158     /* If the SMBus is still busy, we give up */
0159     if (timeout == MAX_TIMEOUT) {
0160         result = -ETIMEDOUT;
0161         dev_err(&vt596_adapter.dev, "SMBus timeout!\n");
0162     }
0163 
0164     if (temp & 0x10) {
0165         result = -EIO;
0166         dev_err(&vt596_adapter.dev, "Transaction failed (0x%02x)\n",
0167             size);
0168     }
0169 
0170     if (temp & 0x08) {
0171         result = -EIO;
0172         dev_err(&vt596_adapter.dev, "SMBus collision!\n");
0173     }
0174 
0175     if (temp & 0x04) {
0176         result = -ENXIO;
0177         dev_dbg(&vt596_adapter.dev, "No response\n");
0178     }
0179 
0180     /* Resetting status register */
0181     if (temp & 0x1F)
0182         outb_p(temp, SMBHSTSTS);
0183 
0184     vt596_dump_regs("Transaction (post)", size);
0185 
0186     return result;
0187 }
0188 
0189 /* Return negative errno on error, 0 on success */
0190 static s32 vt596_access(struct i2c_adapter *adap, u16 addr,
0191         unsigned short flags, char read_write, u8 command,
0192         int size, union i2c_smbus_data *data)
0193 {
0194     int i;
0195     int status;
0196 
0197     switch (size) {
0198     case I2C_SMBUS_QUICK:
0199         size = VT596_QUICK;
0200         break;
0201     case I2C_SMBUS_BYTE:
0202         if (read_write == I2C_SMBUS_WRITE)
0203             outb_p(command, SMBHSTCMD);
0204         size = VT596_BYTE;
0205         break;
0206     case I2C_SMBUS_BYTE_DATA:
0207         outb_p(command, SMBHSTCMD);
0208         if (read_write == I2C_SMBUS_WRITE)
0209             outb_p(data->byte, SMBHSTDAT0);
0210         size = VT596_BYTE_DATA;
0211         break;
0212     case I2C_SMBUS_WORD_DATA:
0213         outb_p(command, SMBHSTCMD);
0214         if (read_write == I2C_SMBUS_WRITE) {
0215             outb_p(data->word & 0xff, SMBHSTDAT0);
0216             outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
0217         }
0218         size = VT596_WORD_DATA;
0219         break;
0220     case I2C_SMBUS_PROC_CALL:
0221         outb_p(command, SMBHSTCMD);
0222         outb_p(data->word & 0xff, SMBHSTDAT0);
0223         outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
0224         size = VT596_PROC_CALL;
0225         break;
0226     case I2C_SMBUS_I2C_BLOCK_DATA:
0227         if (!(vt596_features & FEATURE_I2CBLOCK))
0228             goto exit_unsupported;
0229         if (read_write == I2C_SMBUS_READ)
0230             outb_p(data->block[0], SMBHSTDAT0);
0231         fallthrough;
0232     case I2C_SMBUS_BLOCK_DATA:
0233         outb_p(command, SMBHSTCMD);
0234         if (read_write == I2C_SMBUS_WRITE) {
0235             u8 len = data->block[0];
0236             if (len > I2C_SMBUS_BLOCK_MAX)
0237                 len = I2C_SMBUS_BLOCK_MAX;
0238             outb_p(len, SMBHSTDAT0);
0239             inb_p(SMBHSTCNT);   /* Reset SMBBLKDAT */
0240             for (i = 1; i <= len; i++)
0241                 outb_p(data->block[i], SMBBLKDAT);
0242         }
0243         size = (size == I2C_SMBUS_I2C_BLOCK_DATA) ?
0244                VT596_I2C_BLOCK_DATA : VT596_BLOCK_DATA;
0245         break;
0246     default:
0247         goto exit_unsupported;
0248     }
0249 
0250     outb_p(((addr & 0x7f) << 1) | read_write, SMBHSTADD);
0251 
0252     status = vt596_transaction(size);
0253     if (status)
0254         return status;
0255 
0256     if (size == VT596_PROC_CALL)
0257         read_write = I2C_SMBUS_READ;
0258 
0259     if ((read_write == I2C_SMBUS_WRITE) || (size == VT596_QUICK))
0260         return 0;
0261 
0262     switch (size) {
0263     case VT596_BYTE:
0264     case VT596_BYTE_DATA:
0265         data->byte = inb_p(SMBHSTDAT0);
0266         break;
0267     case VT596_WORD_DATA:
0268     case VT596_PROC_CALL:
0269         data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
0270         break;
0271     case VT596_I2C_BLOCK_DATA:
0272     case VT596_BLOCK_DATA:
0273         data->block[0] = inb_p(SMBHSTDAT0);
0274         if (data->block[0] > I2C_SMBUS_BLOCK_MAX)
0275             data->block[0] = I2C_SMBUS_BLOCK_MAX;
0276         inb_p(SMBHSTCNT);   /* Reset SMBBLKDAT */
0277         for (i = 1; i <= data->block[0]; i++)
0278             data->block[i] = inb_p(SMBBLKDAT);
0279         break;
0280     }
0281     return 0;
0282 
0283 exit_unsupported:
0284     dev_warn(&vt596_adapter.dev, "Unsupported transaction %d\n",
0285          size);
0286     return -EOPNOTSUPP;
0287 }
0288 
0289 static u32 vt596_func(struct i2c_adapter *adapter)
0290 {
0291     u32 func = I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
0292         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
0293         I2C_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_BLOCK_DATA;
0294 
0295     if (vt596_features & FEATURE_I2CBLOCK)
0296         func |= I2C_FUNC_SMBUS_I2C_BLOCK;
0297     return func;
0298 }
0299 
0300 static const struct i2c_algorithm smbus_algorithm = {
0301     .smbus_xfer = vt596_access,
0302     .functionality  = vt596_func,
0303 };
0304 
0305 static struct i2c_adapter vt596_adapter = {
0306     .owner      = THIS_MODULE,
0307     .class      = I2C_CLASS_HWMON | I2C_CLASS_SPD,
0308     .algo       = &smbus_algorithm,
0309 };
0310 
0311 static int vt596_probe(struct pci_dev *pdev,
0312                const struct pci_device_id *id)
0313 {
0314     unsigned char temp;
0315     int error;
0316 
0317     /* Determine the address of the SMBus areas */
0318     if (force_addr) {
0319         vt596_smba = force_addr & 0xfff0;
0320         force = 0;
0321         goto found;
0322     }
0323 
0324     if ((pci_read_config_word(pdev, id->driver_data, &vt596_smba)) ||
0325         !(vt596_smba & 0x0001)) {
0326         /* try 2nd address and config reg. for 596 */
0327         if (id->device == PCI_DEVICE_ID_VIA_82C596_3 &&
0328             !pci_read_config_word(pdev, SMBBA2, &vt596_smba) &&
0329             (vt596_smba & 0x0001)) {
0330             SMBHSTCFG = 0x84;
0331         } else {
0332             /* no matches at all */
0333             dev_err(&pdev->dev, "Cannot configure "
0334                 "SMBus I/O Base address\n");
0335             return -ENODEV;
0336         }
0337     }
0338 
0339     vt596_smba &= 0xfff0;
0340     if (vt596_smba == 0) {
0341         dev_err(&pdev->dev, "SMBus base address "
0342             "uninitialized - upgrade BIOS or use "
0343             "force_addr=0xaddr\n");
0344         return -ENODEV;
0345     }
0346 
0347 found:
0348     error = acpi_check_region(vt596_smba, 8, vt596_driver.name);
0349     if (error)
0350         return -ENODEV;
0351 
0352     if (!request_region(vt596_smba, 8, vt596_driver.name)) {
0353         dev_err(&pdev->dev, "SMBus region 0x%x already in use!\n",
0354             vt596_smba);
0355         return -ENODEV;
0356     }
0357 
0358     pci_read_config_byte(pdev, SMBHSTCFG, &temp);
0359     /* If force_addr is set, we program the new address here. Just to make
0360        sure, we disable the VT596 first. */
0361     if (force_addr) {
0362         pci_write_config_byte(pdev, SMBHSTCFG, temp & 0xfe);
0363         pci_write_config_word(pdev, id->driver_data, vt596_smba);
0364         pci_write_config_byte(pdev, SMBHSTCFG, temp | 0x01);
0365         dev_warn(&pdev->dev, "WARNING: SMBus interface set to new "
0366              "address 0x%04x!\n", vt596_smba);
0367     } else if (!(temp & 0x01)) {
0368         if (force) {
0369             /* NOTE: This assumes I/O space and other allocations
0370              * WERE done by the Bios!  Don't complain if your
0371              * hardware does weird things after enabling this.
0372              * :') Check for Bios updates before resorting to
0373              * this.
0374              */
0375             pci_write_config_byte(pdev, SMBHSTCFG, temp | 0x01);
0376             dev_info(&pdev->dev, "Enabling SMBus device\n");
0377         } else {
0378             dev_err(&pdev->dev, "SMBUS: Error: Host SMBus "
0379                 "controller not enabled! - upgrade BIOS or "
0380                 "use force=1\n");
0381             error = -ENODEV;
0382             goto release_region;
0383         }
0384     }
0385 
0386     dev_dbg(&pdev->dev, "VT596_smba = 0x%X\n", vt596_smba);
0387 
0388     switch (pdev->device) {
0389     case PCI_DEVICE_ID_VIA_CX700:
0390     case PCI_DEVICE_ID_VIA_VX800:
0391     case PCI_DEVICE_ID_VIA_VX855:
0392     case PCI_DEVICE_ID_VIA_VX900:
0393     case PCI_DEVICE_ID_VIA_8251:
0394     case PCI_DEVICE_ID_VIA_8237:
0395     case PCI_DEVICE_ID_VIA_8237A:
0396     case PCI_DEVICE_ID_VIA_8237S:
0397     case PCI_DEVICE_ID_VIA_8235:
0398     case PCI_DEVICE_ID_VIA_8233A:
0399     case PCI_DEVICE_ID_VIA_8233_0:
0400         vt596_features |= FEATURE_I2CBLOCK;
0401         break;
0402     case PCI_DEVICE_ID_VIA_82C686_4:
0403         /* The VT82C686B (rev 0x40) does support I2C block
0404            transactions, but the VT82C686A (rev 0x30) doesn't */
0405         if (pdev->revision >= 0x40)
0406             vt596_features |= FEATURE_I2CBLOCK;
0407         break;
0408     }
0409 
0410     vt596_adapter.dev.parent = &pdev->dev;
0411     snprintf(vt596_adapter.name, sizeof(vt596_adapter.name),
0412          "SMBus Via Pro adapter at %04x", vt596_smba);
0413 
0414     vt596_pdev = pci_dev_get(pdev);
0415     error = i2c_add_adapter(&vt596_adapter);
0416     if (error) {
0417         pci_dev_put(vt596_pdev);
0418         vt596_pdev = NULL;
0419         goto release_region;
0420     }
0421 
0422     /* Always return failure here.  This is to allow other drivers to bind
0423      * to this pci device.  We don't really want to have control over the
0424      * pci device, we only wanted to read as few register values from it.
0425      */
0426     return -ENODEV;
0427 
0428 release_region:
0429     release_region(vt596_smba, 8);
0430     return error;
0431 }
0432 
0433 static const struct pci_device_id vt596_ids[] = {
0434     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C596_3),
0435       .driver_data = SMBBA1 },
0436     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C596B_3),
0437       .driver_data = SMBBA1 },
0438     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C686_4),
0439       .driver_data = SMBBA1 },
0440     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8233_0),
0441       .driver_data = SMBBA3 },
0442     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8233A),
0443       .driver_data = SMBBA3 },
0444     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8235),
0445       .driver_data = SMBBA3 },
0446     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237),
0447       .driver_data = SMBBA3 },
0448     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237A),
0449       .driver_data = SMBBA3 },
0450     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237S),
0451       .driver_data = SMBBA3 },
0452     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8231_4),
0453       .driver_data = SMBBA1 },
0454     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8251),
0455       .driver_data = SMBBA3 },
0456     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_CX700),
0457       .driver_data = SMBBA3 },
0458     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX800),
0459       .driver_data = SMBBA3 },
0460     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX855),
0461       .driver_data = SMBBA3 },
0462     { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX900),
0463       .driver_data = SMBBA3 },
0464     { 0, }
0465 };
0466 
0467 MODULE_DEVICE_TABLE(pci, vt596_ids);
0468 
0469 static struct pci_driver vt596_driver = {
0470     .name       = "vt596_smbus",
0471     .id_table   = vt596_ids,
0472     .probe      = vt596_probe,
0473 };
0474 
0475 static int __init i2c_vt596_init(void)
0476 {
0477     return pci_register_driver(&vt596_driver);
0478 }
0479 
0480 
0481 static void __exit i2c_vt596_exit(void)
0482 {
0483     pci_unregister_driver(&vt596_driver);
0484     if (vt596_pdev != NULL) {
0485         i2c_del_adapter(&vt596_adapter);
0486         release_region(vt596_smba, 8);
0487         pci_dev_put(vt596_pdev);
0488         vt596_pdev = NULL;
0489     }
0490 }
0491 
0492 MODULE_AUTHOR("Kyosti Malkki <kmalkki@cc.hut.fi>");
0493 MODULE_AUTHOR("Mark D. Studebaker <mdsxyz123@yahoo.com>");
0494 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
0495 MODULE_DESCRIPTION("vt82c596 SMBus driver");
0496 MODULE_LICENSE("GPL");
0497 
0498 module_init(i2c_vt596_init);
0499 module_exit(i2c_vt596_exit);
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