/sys/dev/imcsmb/imcsmb.c
C | 556 lines | 233 code | 63 blank | 260 comment | 38 complexity | c4e5d14b12821538eaaf1bec819cd9b3 MD5 | raw file
- /*-
- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
- *
- * Authors: Joe Kloss; Ravi Pokala (rpokala@freebsd.org)
- *
- * Copyright (c) 2017-2018 Panasas
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * $FreeBSD$
- */
- /* A detailed description of this device is present in imcsmb_pci.c */
- #include <sys/param.h>
- #include <sys/systm.h>
- #include <sys/kernel.h>
- #include <sys/module.h>
- #include <sys/endian.h>
- #include <sys/errno.h>
- #include <sys/lock.h>
- #include <sys/mutex.h>
- #include <sys/syslog.h>
- #include <sys/bus.h>
- #include <machine/bus.h>
- #include <machine/atomic.h>
- #include <dev/pci/pcivar.h>
- #include <dev/pci/pcireg.h>
- #include <dev/smbus/smbconf.h>
- #include "imcsmb_reg.h"
- #include "imcsmb_var.h"
- /* Device methods */
- static int imcsmb_attach(device_t dev);
- static int imcsmb_detach(device_t dev);
- static int imcsmb_probe(device_t dev);
- /* SMBus methods */
- static int imcsmb_callback(device_t dev, int index, void *data);
- static int imcsmb_readb(device_t dev, u_char slave, char cmd, char *byte);
- static int imcsmb_readw(device_t dev, u_char slave, char cmd, short *word);
- static int imcsmb_writeb(device_t dev, u_char slave, char cmd, char byte);
- static int imcsmb_writew(device_t dev, u_char slave, char cmd, short word);
- /* All the read/write methods wrap around this. */
- static int imcsmb_transfer(device_t dev, u_char slave, char cmd, void *data,
- int word_op, int write_op);
- /**
- * device_attach() method. Set up the softc, including getting the set of the
- * parent imcsmb_pci's registers that we will use. Create the smbus(4) device,
- * which any SMBus slave device drivers will connect to.
- *
- * @author rpokala
- *
- * @param[in,out] dev
- * Device being attached.
- */
- static int
- imcsmb_attach(device_t dev)
- {
- struct imcsmb_softc *sc;
- int rc;
- /* Initialize private state */
- sc = device_get_softc(dev);
- sc->dev = dev;
- sc->imcsmb_pci = device_get_parent(dev);
- sc->regs = device_get_ivars(dev);
- /* Create the smbus child */
- sc->smbus = device_add_child(dev, "smbus", -1);
- if (sc->smbus == NULL) {
- /* Nothing has been allocated, so there's no cleanup. */
- device_printf(dev, "Child smbus not added\n");
- rc = ENXIO;
- goto out;
- }
- /* Attach the smbus child. */
- if ((rc = bus_generic_attach(dev)) != 0) {
- device_printf(dev, "Failed to attach smbus: %d\n", rc);
- }
- out:
- return (rc);
- }
- /**
- * device_detach() method. attach() didn't do any allocations, so all that's
- * needed here is to free up any downstream drivers and children.
- *
- * @author Joe Kloss
- *
- * @param[in] dev
- * Device being detached.
- */
- static int
- imcsmb_detach(device_t dev)
- {
- int rc;
- /* Detach any attached drivers */
- rc = bus_generic_detach(dev);
- if (rc == 0) {
- /* Remove all children */
- rc = device_delete_children(dev);
- }
- return (rc);
- }
- /**
- * device_probe() method. All the actual probing was done by the imcsmb_pci
- * parent, so just report success.
- *
- * @author Joe Kloss
- *
- * @param[in,out] dev
- * Device being probed.
- */
- static int
- imcsmb_probe(device_t dev)
- {
- device_set_desc(dev, "iMC SMBus controller");
- return (BUS_PROBE_DEFAULT);
- }
- /**
- * smbus_callback() method. Call the parent imcsmb_pci's request or release
- * function to quiesce / restart firmware tasks which might use the SMBus.
- *
- * @author rpokala
- *
- * @param[in] dev
- * Device being requested or released.
- *
- * @param[in] index
- * Either SMB_REQUEST_BUS or SMB_RELEASE_BUS.
- *
- * @param[in] data
- * Tell's the rest of the SMBus subsystem to allow or disallow waiting;
- * this driver only works with SMB_DONTWAIT.
- */
- static int
- imcsmb_callback(device_t dev, int index, void *data)
- {
- struct imcsmb_softc *sc;
- int *how;
- int rc;
- sc = device_get_softc(dev);
- how = (int *) data;
- switch (index) {
- case SMB_REQUEST_BUS: {
- if (*how != SMB_DONTWAIT) {
- rc = EINVAL;
- goto out;
- }
- rc = imcsmb_pci_request_bus(sc->imcsmb_pci);
- break;
- }
- case SMB_RELEASE_BUS:
- imcsmb_pci_release_bus(sc->imcsmb_pci);
- rc = 0;
- break;
- default:
- rc = EINVAL;
- break;
- }
- out:
- return (rc);
- }
- /**
- * smbus_readb() method. Thin wrapper around imcsmb_transfer().
- *
- * @author Joe Kloss
- *
- * @param[in] dev
- *
- * @param[in] slave
- * The SMBus address of the target device.
- *
- * @param[in] cmd
- * The SMBus command for the target device; this is the offset for SPDs,
- * or the register number for TSODs.
- *
- * @param[out] byte
- * The byte which was read.
- */
- static int
- imcsmb_readb(device_t dev, u_char slave, char cmd, char *byte)
- {
- return (imcsmb_transfer(dev, slave, cmd, byte, FALSE, FALSE));
- }
- /**
- * smbus_readw() method. Thin wrapper around imcsmb_transfer().
- *
- * @author Joe Kloss
- *
- * @param[in] dev
- *
- * @param[in] slave
- * The SMBus address of the target device.
- *
- * @param[in] cmd
- * The SMBus command for the target device; this is the offset for SPDs,
- * or the register number for TSODs.
- *
- * @param[out] word
- * The word which was read.
- */
- static int
- imcsmb_readw(device_t dev, u_char slave, char cmd, short *word)
- {
- return (imcsmb_transfer(dev, slave, cmd, word, TRUE, FALSE));
- }
- /**
- * smbus_writeb() method. Thin wrapper around imcsmb_transfer().
- *
- * @author Joe Kloss
- *
- * @param[in] dev
- *
- * @param[in] slave
- * The SMBus address of the target device.
- *
- * @param[in] cmd
- * The SMBus command for the target device; this is the offset for SPDs,
- * or the register number for TSODs.
- *
- * @param[in] byte
- * The byte to write.
- */
- static int
- imcsmb_writeb(device_t dev, u_char slave, char cmd, char byte)
- {
- return (imcsmb_transfer(dev, slave, cmd, &byte, FALSE, TRUE));
- }
- /**
- * smbus_writew() method. Thin wrapper around imcsmb_transfer().
- *
- * @author Joe Kloss
- *
- * @param[in] dev
- *
- * @param[in] slave
- * The SMBus address of the target device.
- *
- * @param[in] cmd
- * The SMBus command for the target device; this is the offset for SPDs,
- * or the register number for TSODs.
- *
- * @param[in] word
- * The word to write.
- */
- static int
- imcsmb_writew(device_t dev, u_char slave, char cmd, short word)
- {
- return (imcsmb_transfer(dev, slave, cmd, &word, TRUE, TRUE));
- }
- /**
- * Manipulate the PCI control registers to read data from or write data to the
- * SMBus controller.
- *
- * @author Joe Kloss, rpokala
- *
- * @param[in] dev
- *
- * @param[in] slave
- * The SMBus address of the target device.
- *
- * @param[in] cmd
- * The SMBus command for the target device; this is the offset for SPDs,
- * or the register number for TSODs.
- *
- * @param[in,out] data
- * Pointer to either the value to be written, or where to place the value
- * which was read.
- *
- * @param[in] word_op
- * Bool: is this a word operation?
- *
- * @param[in] write_op
- * Bool: is this a write operation?
- */
- static int
- imcsmb_transfer(device_t dev, u_char slave, char cmd, void *data, int word_op,
- int write_op)
- {
- struct imcsmb_softc *sc;
- int i;
- int rc;
- uint32_t cmd_val;
- uint32_t cntl_val;
- uint32_t orig_cntl_val;
- uint32_t stat_val;
- uint16_t *word;
- uint16_t lword;
- uint8_t *byte;
- uint8_t lbyte;
- sc = device_get_softc(dev);
- byte = data;
- word = data;
- lbyte = *byte;
- lword = *word;
- /* We modify the value of the control register; save the original, so
- * we can restore it later
- */
- orig_cntl_val = pci_read_config(sc->imcsmb_pci,
- sc->regs->smb_cntl, 4);
- cntl_val = orig_cntl_val;
- /*
- * Set up the SMBCNTL register
- */
- /* [31:28] Clear the existing value of the DTI bits, then set them to
- * the four high bits of the slave address.
- */
- cntl_val &= ~IMCSMB_CNTL_DTI_MASK;
- cntl_val |= ((uint32_t) slave & 0xf0) << 24;
- /* [27:27] Set the CLK_OVERRIDE bit, to enable normal operation */
- cntl_val |= IMCSMB_CNTL_CLK_OVERRIDE;
- /* [26:26] Clear the WRITE_DISABLE bit; the datasheet says this isn't
- * necessary, but empirically, it is.
- */
- cntl_val &= ~IMCSMB_CNTL_WRITE_DISABLE_BIT;
- /* [9:9] Clear the POLL_EN bit, to stop the hardware TSOD polling. */
- cntl_val &= ~IMCSMB_CNTL_POLL_EN;
- /*
- * Set up the SMBCMD register
- */
- /* [31:31] Set the TRIGGER bit; when this gets written, the controller
- * will issue the command.
- */
- cmd_val = IMCSMB_CMD_TRIGGER_BIT;
- /* [29:29] For word operations, set the WORD_ACCESS bit. */
- if (word_op) {
- cmd_val |= IMCSMB_CMD_WORD_ACCESS;
- }
- /* [27:27] For write operations, set the WRITE bit. */
- if (write_op) {
- cmd_val |= IMCSMB_CMD_WRITE_BIT;
- }
- /* [26:24] The three non-DTI, non-R/W bits of the slave address. */
- cmd_val |= (uint32_t) ((slave & 0xe) << 23);
- /* [23:16] The command (offset in the case of an EEPROM, or register in
- * the case of TSOD or NVDIMM controller).
- */
- cmd_val |= (uint32_t) ((uint8_t) cmd << 16);
- /* [15:0] The data to be written for a write operation. */
- if (write_op) {
- if (word_op) {
- /* The datasheet says the controller uses different
- * endianness for word operations on I2C vs SMBus!
- * I2C: [15:8] = MSB; [7:0] = LSB
- * SMB: [15:8] = LSB; [7:0] = MSB
- * As a practical matter, this controller is very
- * specifically for use with DIMMs, the SPD (and
- * NVDIMM controllers) are only accessed as bytes,
- * the temperature sensor is only accessed as words, and
- * the temperature sensors are I2C. Thus, byte-swap the
- * word.
- */
- lword = htobe16(lword);
- } else {
- /* For byte operations, the data goes in the LSB, and
- * the MSB is a don't care.
- */
- lword = (uint16_t) (lbyte & 0xff);
- }
- cmd_val |= lword;
- }
- /* Write the updated value to the control register first, to disable
- * the hardware TSOD polling.
- */
- pci_write_config(sc->imcsmb_pci, sc->regs->smb_cntl, cntl_val, 4);
- /* Poll on the BUSY bit in the status register until clear, or timeout.
- * We just cleared the auto-poll bit, so we need to make sure the device
- * is idle before issuing a command. We can safely timeout after 35 ms,
- * as this is the maximum time the SMBus spec allows for a transaction.
- */
- for (i = 4; i != 0; i--) {
- stat_val = pci_read_config(sc->imcsmb_pci, sc->regs->smb_stat,
- 4);
- if ((stat_val & IMCSMB_STATUS_BUSY_BIT) == 0) {
- break;
- }
- pause("imcsmb", 10 * hz / 1000);
- }
- if (i == 0) {
- device_printf(sc->dev,
- "transfer: timeout waiting for device to settle\n");
- }
- /* Now that polling has stopped, we can write the command register. This
- * starts the SMBus command.
- */
- pci_write_config(sc->imcsmb_pci, sc->regs->smb_cmd, cmd_val, 4);
- /* Wait for WRITE_DATA_DONE/READ_DATA_VALID to be set, or timeout and
- * fail. We wait up to 35ms.
- */
- for (i = 35000; i != 0; i -= 10)
- {
- DELAY(10);
- stat_val = pci_read_config(sc->imcsmb_pci, sc->regs->smb_stat,
- 4);
- /* For a write, the bits holding the data contain the data being
- * written. You'd think that would cause the READ_DATA_VALID bit
- * to be cleared, because the data bits no longer contain valid
- * data from the most recent read operation. While that would be
- * logical, that's not the case here: READ_DATA_VALID is only
- * cleared when starting a read operation, and WRITE_DATA_DONE
- * is only cleared when starting a write operation.
- */
- if (write_op) {
- if ((stat_val & IMCSMB_STATUS_WRITE_DATA_DONE) != 0) {
- break;
- }
- } else {
- if ((stat_val & IMCSMB_STATUS_READ_DATA_VALID) != 0) {
- break;
- }
- }
- }
- if (i == 0) {
- rc = SMB_ETIMEOUT;
- device_printf(dev, "transfer timeout\n");
- goto out;
- }
- /* It is generally the case that this bit indicates non-ACK, but it
- * could also indicate other bus errors. There's no way to tell the
- * difference.
- */
- if ((stat_val & IMCSMB_STATUS_BUS_ERROR_BIT) != 0) {
- /* While it is not documented, empirically, SPD page-change
- * commands (writes with DTI = 0x60) always complete with the
- * error bit set. So, ignore it in those cases.
- */
- if ((slave & 0xf0) != 0x60) {
- rc = SMB_ENOACK;
- goto out;
- }
- }
- /* For a read operation, copy the data out */
- if (write_op == 0) {
- if (word_op) {
- /* The data is returned in bits [15:0]; as discussed
- * above, byte-swap.
- */
- lword = (uint16_t) (stat_val & 0xffff);
- lword = htobe16(lword);
- *word = lword;
- } else {
- /* The data is returned in bits [7:0] */
- lbyte = (uint8_t) (stat_val & 0xff);
- *byte = lbyte;
- }
- }
- /* A lack of an error is, de facto, success. */
- rc = SMB_ENOERR;
- out:
- /* Restore the original value of the control register. */
- pci_write_config(sc->imcsmb_pci, sc->regs->smb_cntl, orig_cntl_val, 4);
- return (rc);
- }
- /* Our device class */
- static devclass_t imcsmb_devclass;
- /* Device methods */
- static device_method_t imcsmb_methods[] = {
- /* Device interface */
- DEVMETHOD(device_attach, imcsmb_attach),
- DEVMETHOD(device_detach, imcsmb_detach),
- DEVMETHOD(device_probe, imcsmb_probe),
- /* smbus methods */
- DEVMETHOD(smbus_callback, imcsmb_callback),
- DEVMETHOD(smbus_readb, imcsmb_readb),
- DEVMETHOD(smbus_readw, imcsmb_readw),
- DEVMETHOD(smbus_writeb, imcsmb_writeb),
- DEVMETHOD(smbus_writew, imcsmb_writew),
- DEVMETHOD_END
- };
- static driver_t imcsmb_driver = {
- .name = "imcsmb",
- .methods = imcsmb_methods,
- .size = sizeof(struct imcsmb_softc),
- };
- DRIVER_MODULE(imcsmb, imcsmb_pci, imcsmb_driver, imcsmb_devclass, 0, 0);
- MODULE_DEPEND(imcsmb, smbus, SMBUS_MINVER, SMBUS_PREFVER, SMBUS_MAXVER);
- MODULE_VERSION(imcsmb, 1);
- DRIVER_MODULE(smbus, imcsmb, smbus_driver, smbus_devclass, 0, 0);
- /* vi: set ts=8 sw=4 sts=8 noet: */