linux/drivers/mailbox/pcc.c
Keith Busch 60574d1e05 acpi: Create subtable parsing infrastructure
Parsing entries in an ACPI table had assumed a generic header
structure. There is no standard ACPI header, though, so less common
layouts with different field sizes required custom parsers to go through
their subtable entry list.

Create the infrastructure for adding different table types so parsing
the entries array may be more reused for all ACPI system tables and
the common code doesn't need to be duplicated.

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Tested-by: Brice Goglin <Brice.Goglin@inria.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-04 18:41:12 +02:00

621 lines
17 KiB
C

/*
* Copyright (C) 2014 Linaro Ltd.
* Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
*
* 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.
*
* PCC (Platform Communication Channel) is defined in the ACPI 5.0+
* specification. It is a mailbox like mechanism to allow clients
* such as CPPC (Collaborative Processor Performance Control), RAS
* (Reliability, Availability and Serviceability) and MPST (Memory
* Node Power State Table) to talk to the platform (e.g. BMC) through
* shared memory regions as defined in the PCC table entries. The PCC
* specification supports a Doorbell mechanism for the PCC clients
* to notify the platform about new data. This Doorbell information
* is also specified in each PCC table entry.
*
* Typical high level flow of operation is:
*
* PCC Reads:
* * Client tries to acquire a channel lock.
* * After it is acquired it writes READ cmd in communication region cmd
* address.
* * Client issues mbox_send_message() which rings the PCC doorbell
* for its PCC channel.
* * If command completes, then client has control over channel and
* it can proceed with its reads.
* * Client releases lock.
*
* PCC Writes:
* * Client tries to acquire channel lock.
* * Client writes to its communication region after it acquires a
* channel lock.
* * Client writes WRITE cmd in communication region cmd address.
* * Client issues mbox_send_message() which rings the PCC doorbell
* for its PCC channel.
* * If command completes, then writes have succeded and it can release
* the channel lock.
*
* There is a Nominal latency defined for each channel which indicates
* how long to wait until a command completes. If command is not complete
* the client needs to retry or assume failure.
*
* For more details about PCC, please see the ACPI specification from
* http://www.uefi.org/ACPIv5.1 Section 14.
*
* This file implements PCC as a Mailbox controller and allows for PCC
* clients to be implemented as its Mailbox Client Channels.
*/
#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/platform_device.h>
#include <linux/mailbox_controller.h>
#include <linux/mailbox_client.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <acpi/pcc.h>
#include "mailbox.h"
#define MBOX_IRQ_NAME "pcc-mbox"
static struct mbox_chan *pcc_mbox_channels;
/* Array of cached virtual address for doorbell registers */
static void __iomem **pcc_doorbell_vaddr;
/* Array of cached virtual address for doorbell ack registers */
static void __iomem **pcc_doorbell_ack_vaddr;
/* Array of doorbell interrupts */
static int *pcc_doorbell_irq;
static struct mbox_controller pcc_mbox_ctrl = {};
/**
* get_pcc_channel - Given a PCC subspace idx, get
* the respective mbox_channel.
* @id: PCC subspace index.
*
* Return: ERR_PTR(errno) if error, else pointer
* to mbox channel.
*/
static struct mbox_chan *get_pcc_channel(int id)
{
if (id < 0 || id >= pcc_mbox_ctrl.num_chans)
return ERR_PTR(-ENOENT);
return &pcc_mbox_channels[id];
}
/*
* PCC can be used with perf critical drivers such as CPPC
* So it makes sense to locally cache the virtual address and
* use it to read/write to PCC registers such as doorbell register
*
* The below read_register and write_registers are used to read and
* write from perf critical registers such as PCC doorbell register
*/
static int read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width)
{
int ret_val = 0;
switch (bit_width) {
case 8:
*val = readb(vaddr);
break;
case 16:
*val = readw(vaddr);
break;
case 32:
*val = readl(vaddr);
break;
case 64:
*val = readq(vaddr);
break;
default:
pr_debug("Error: Cannot read register of %u bit width",
bit_width);
ret_val = -EFAULT;
break;
}
return ret_val;
}
static int write_register(void __iomem *vaddr, u64 val, unsigned int bit_width)
{
int ret_val = 0;
switch (bit_width) {
case 8:
writeb(val, vaddr);
break;
case 16:
writew(val, vaddr);
break;
case 32:
writel(val, vaddr);
break;
case 64:
writeq(val, vaddr);
break;
default:
pr_debug("Error: Cannot write register of %u bit width",
bit_width);
ret_val = -EFAULT;
break;
}
return ret_val;
}
/**
* pcc_map_interrupt - Map a PCC subspace GSI to a linux IRQ number
* @interrupt: GSI number.
* @flags: interrupt flags
*
* Returns: a valid linux IRQ number on success
* 0 or -EINVAL on failure
*/
static int pcc_map_interrupt(u32 interrupt, u32 flags)
{
int trigger, polarity;
if (!interrupt)
return 0;
trigger = (flags & ACPI_PCCT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
: ACPI_LEVEL_SENSITIVE;
polarity = (flags & ACPI_PCCT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
: ACPI_ACTIVE_HIGH;
return acpi_register_gsi(NULL, interrupt, trigger, polarity);
}
/**
* pcc_mbox_irq - PCC mailbox interrupt handler
*/
static irqreturn_t pcc_mbox_irq(int irq, void *p)
{
struct acpi_generic_address *doorbell_ack;
struct acpi_pcct_hw_reduced *pcct_ss;
struct mbox_chan *chan = p;
u64 doorbell_ack_preserve;
u64 doorbell_ack_write;
u64 doorbell_ack_val;
int ret;
pcct_ss = chan->con_priv;
mbox_chan_received_data(chan, NULL);
if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
struct acpi_pcct_hw_reduced_type2 *pcct2_ss = chan->con_priv;
u32 id = chan - pcc_mbox_channels;
doorbell_ack = &pcct2_ss->platform_ack_register;
doorbell_ack_preserve = pcct2_ss->ack_preserve_mask;
doorbell_ack_write = pcct2_ss->ack_write_mask;
ret = read_register(pcc_doorbell_ack_vaddr[id],
&doorbell_ack_val,
doorbell_ack->bit_width);
if (ret)
return IRQ_NONE;
ret = write_register(pcc_doorbell_ack_vaddr[id],
(doorbell_ack_val & doorbell_ack_preserve)
| doorbell_ack_write,
doorbell_ack->bit_width);
if (ret)
return IRQ_NONE;
}
return IRQ_HANDLED;
}
/**
* pcc_mbox_request_channel - PCC clients call this function to
* request a pointer to their PCC subspace, from which they
* can get the details of communicating with the remote.
* @cl: Pointer to Mailbox client, so we know where to bind the
* Channel.
* @subspace_id: The PCC Subspace index as parsed in the PCC client
* ACPI package. This is used to lookup the array of PCC
* subspaces as parsed by the PCC Mailbox controller.
*
* Return: Pointer to the Mailbox Channel if successful or
* ERR_PTR.
*/
struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
int subspace_id)
{
struct device *dev = pcc_mbox_ctrl.dev;
struct mbox_chan *chan;
unsigned long flags;
/*
* Each PCC Subspace is a Mailbox Channel.
* The PCC Clients get their PCC Subspace ID
* from their own tables and pass it here.
* This returns a pointer to the PCC subspace
* for the Client to operate on.
*/
chan = get_pcc_channel(subspace_id);
if (IS_ERR(chan) || chan->cl) {
dev_err(dev, "Channel not found for idx: %d\n", subspace_id);
return ERR_PTR(-EBUSY);
}
spin_lock_irqsave(&chan->lock, flags);
chan->msg_free = 0;
chan->msg_count = 0;
chan->active_req = NULL;
chan->cl = cl;
init_completion(&chan->tx_complete);
if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
chan->txdone_method = TXDONE_BY_ACK;
spin_unlock_irqrestore(&chan->lock, flags);
if (pcc_doorbell_irq[subspace_id] > 0) {
int rc;
rc = devm_request_irq(dev, pcc_doorbell_irq[subspace_id],
pcc_mbox_irq, 0, MBOX_IRQ_NAME, chan);
if (unlikely(rc)) {
dev_err(dev, "failed to register PCC interrupt %d\n",
pcc_doorbell_irq[subspace_id]);
pcc_mbox_free_channel(chan);
chan = ERR_PTR(rc);
}
}
return chan;
}
EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
/**
* pcc_mbox_free_channel - Clients call this to free their Channel.
*
* @chan: Pointer to the mailbox channel as returned by
* pcc_mbox_request_channel()
*/
void pcc_mbox_free_channel(struct mbox_chan *chan)
{
u32 id = chan - pcc_mbox_channels;
unsigned long flags;
if (!chan || !chan->cl)
return;
if (id >= pcc_mbox_ctrl.num_chans) {
pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
return;
}
if (pcc_doorbell_irq[id] > 0)
devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
spin_lock_irqsave(&chan->lock, flags);
chan->cl = NULL;
chan->active_req = NULL;
if (chan->txdone_method == TXDONE_BY_ACK)
chan->txdone_method = TXDONE_BY_POLL;
spin_unlock_irqrestore(&chan->lock, flags);
}
EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
/**
* pcc_send_data - Called from Mailbox Controller code. Used
* here only to ring the channel doorbell. The PCC client
* specific read/write is done in the client driver in
* order to maintain atomicity over PCC channel once
* OS has control over it. See above for flow of operations.
* @chan: Pointer to Mailbox channel over which to send data.
* @data: Client specific data written over channel. Used here
* only for debug after PCC transaction completes.
*
* Return: Err if something failed else 0 for success.
*/
static int pcc_send_data(struct mbox_chan *chan, void *data)
{
struct acpi_pcct_hw_reduced *pcct_ss = chan->con_priv;
struct acpi_generic_address *doorbell;
u64 doorbell_preserve;
u64 doorbell_val;
u64 doorbell_write;
u32 id = chan - pcc_mbox_channels;
int ret = 0;
if (id >= pcc_mbox_ctrl.num_chans) {
pr_debug("pcc_send_data: Invalid mbox_chan passed\n");
return -ENOENT;
}
doorbell = &pcct_ss->doorbell_register;
doorbell_preserve = pcct_ss->preserve_mask;
doorbell_write = pcct_ss->write_mask;
/* Sync notification from OS to Platform. */
if (pcc_doorbell_vaddr[id]) {
ret = read_register(pcc_doorbell_vaddr[id], &doorbell_val,
doorbell->bit_width);
if (ret)
return ret;
ret = write_register(pcc_doorbell_vaddr[id],
(doorbell_val & doorbell_preserve) | doorbell_write,
doorbell->bit_width);
} else {
ret = acpi_read(&doorbell_val, doorbell);
if (ret)
return ret;
ret = acpi_write((doorbell_val & doorbell_preserve) | doorbell_write,
doorbell);
}
return ret;
}
static const struct mbox_chan_ops pcc_chan_ops = {
.send_data = pcc_send_data,
};
/**
* parse_pcc_subspaces -- Count PCC subspaces defined
* @header: Pointer to the ACPI subtable header under the PCCT.
* @end: End of subtable entry.
*
* Return: If we find a PCC subspace entry of a valid type, return 0.
* Otherwise, return -EINVAL.
*
* This gets called for each entry in the PCC table.
*/
static int parse_pcc_subspace(union acpi_subtable_headers *header,
const unsigned long end)
{
struct acpi_pcct_subspace *ss = (struct acpi_pcct_subspace *) header;
if (ss->header.type < ACPI_PCCT_TYPE_RESERVED)
return 0;
return -EINVAL;
}
/**
* pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register
* There should be one entry per PCC client.
* @id: PCC subspace index.
* @pcct_ss: Pointer to the ACPI subtable header under the PCCT.
*
* Return: 0 for Success, else errno.
*
* This gets called for each entry in the PCC table.
*/
static int pcc_parse_subspace_irq(int id,
struct acpi_pcct_hw_reduced *pcct_ss)
{
pcc_doorbell_irq[id] = pcc_map_interrupt(pcct_ss->platform_interrupt,
(u32)pcct_ss->flags);
if (pcc_doorbell_irq[id] <= 0) {
pr_err("PCC GSI %d not registered\n",
pcct_ss->platform_interrupt);
return -EINVAL;
}
if (pcct_ss->header.type
== ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss;
pcc_doorbell_ack_vaddr[id] = acpi_os_ioremap(
pcct2_ss->platform_ack_register.address,
pcct2_ss->platform_ack_register.bit_width / 8);
if (!pcc_doorbell_ack_vaddr[id]) {
pr_err("Failed to ioremap PCC ACK register\n");
return -ENOMEM;
}
}
return 0;
}
/**
* acpi_pcc_probe - Parse the ACPI tree for the PCCT.
*
* Return: 0 for Success, else errno.
*/
static int __init acpi_pcc_probe(void)
{
struct acpi_table_header *pcct_tbl;
struct acpi_subtable_header *pcct_entry;
struct acpi_table_pcct *acpi_pcct_tbl;
struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED];
int count, i, rc;
acpi_status status = AE_OK;
/* Search for PCCT */
status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
if (ACPI_FAILURE(status) || !pcct_tbl)
return -ENODEV;
/* Set up the subtable handlers */
for (i = ACPI_PCCT_TYPE_GENERIC_SUBSPACE;
i < ACPI_PCCT_TYPE_RESERVED; i++) {
proc[i].id = i;
proc[i].count = 0;
proc[i].handler = parse_pcc_subspace;
}
count = acpi_table_parse_entries_array(ACPI_SIG_PCCT,
sizeof(struct acpi_table_pcct), proc,
ACPI_PCCT_TYPE_RESERVED, MAX_PCC_SUBSPACES);
if (count <= 0 || count > MAX_PCC_SUBSPACES) {
if (count < 0)
pr_warn("Error parsing PCC subspaces from PCCT\n");
else
pr_warn("Invalid PCCT: %d PCC subspaces\n", count);
return -EINVAL;
}
pcc_mbox_channels = kcalloc(count, sizeof(struct mbox_chan),
GFP_KERNEL);
if (!pcc_mbox_channels) {
pr_err("Could not allocate space for PCC mbox channels\n");
return -ENOMEM;
}
pcc_doorbell_vaddr = kcalloc(count, sizeof(void *), GFP_KERNEL);
if (!pcc_doorbell_vaddr) {
rc = -ENOMEM;
goto err_free_mbox;
}
pcc_doorbell_ack_vaddr = kcalloc(count, sizeof(void *), GFP_KERNEL);
if (!pcc_doorbell_ack_vaddr) {
rc = -ENOMEM;
goto err_free_db_vaddr;
}
pcc_doorbell_irq = kcalloc(count, sizeof(int), GFP_KERNEL);
if (!pcc_doorbell_irq) {
rc = -ENOMEM;
goto err_free_db_ack_vaddr;
}
/* Point to the first PCC subspace entry */
pcct_entry = (struct acpi_subtable_header *) (
(unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct));
acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl;
if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL)
pcc_mbox_ctrl.txdone_irq = true;
for (i = 0; i < count; i++) {
struct acpi_generic_address *db_reg;
struct acpi_pcct_subspace *pcct_ss;
pcc_mbox_channels[i].con_priv = pcct_entry;
if (pcct_entry->type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE ||
pcct_entry->type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
struct acpi_pcct_hw_reduced *pcct_hrss;
pcct_hrss = (struct acpi_pcct_hw_reduced *) pcct_entry;
if (pcc_mbox_ctrl.txdone_irq) {
rc = pcc_parse_subspace_irq(i, pcct_hrss);
if (rc < 0)
goto err;
}
}
pcct_ss = (struct acpi_pcct_subspace *) pcct_entry;
/* If doorbell is in system memory cache the virt address */
db_reg = &pcct_ss->doorbell_register;
if (db_reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
pcc_doorbell_vaddr[i] = acpi_os_ioremap(db_reg->address,
db_reg->bit_width/8);
pcct_entry = (struct acpi_subtable_header *)
((unsigned long) pcct_entry + pcct_entry->length);
}
pcc_mbox_ctrl.num_chans = count;
pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl.num_chans);
return 0;
err:
kfree(pcc_doorbell_irq);
err_free_db_ack_vaddr:
kfree(pcc_doorbell_ack_vaddr);
err_free_db_vaddr:
kfree(pcc_doorbell_vaddr);
err_free_mbox:
kfree(pcc_mbox_channels);
return rc;
}
/**
* pcc_mbox_probe - Called when we find a match for the
* PCCT platform device. This is purely used to represent
* the PCCT as a virtual device for registering with the
* generic Mailbox framework.
*
* @pdev: Pointer to platform device returned when a match
* is found.
*
* Return: 0 for Success, else errno.
*/
static int pcc_mbox_probe(struct platform_device *pdev)
{
int ret = 0;
pcc_mbox_ctrl.chans = pcc_mbox_channels;
pcc_mbox_ctrl.ops = &pcc_chan_ops;
pcc_mbox_ctrl.dev = &pdev->dev;
pr_info("Registering PCC driver as Mailbox controller\n");
ret = mbox_controller_register(&pcc_mbox_ctrl);
if (ret) {
pr_err("Err registering PCC as Mailbox controller: %d\n", ret);
ret = -ENODEV;
}
return ret;
}
struct platform_driver pcc_mbox_driver = {
.probe = pcc_mbox_probe,
.driver = {
.name = "PCCT",
.owner = THIS_MODULE,
},
};
static int __init pcc_init(void)
{
int ret;
struct platform_device *pcc_pdev;
if (acpi_disabled)
return -ENODEV;
/* Check if PCC support is available. */
ret = acpi_pcc_probe();
if (ret) {
pr_debug("ACPI PCC probe failed.\n");
return -ENODEV;
}
pcc_pdev = platform_create_bundle(&pcc_mbox_driver,
pcc_mbox_probe, NULL, 0, NULL, 0);
if (IS_ERR(pcc_pdev)) {
pr_debug("Err creating PCC platform bundle\n");
return PTR_ERR(pcc_pdev);
}
return 0;
}
/*
* Make PCC init postcore so that users of this mailbox
* such as the ACPI Processor driver have it available
* at their init.
*/
postcore_initcall(pcc_init);