linux/drivers/mailbox/pcc.c
Huisong Li 3db174e478 mailbox: pcc: Support shared interrupt for multiple subspaces
If the platform acknowledge interrupt is level triggered, then it can
be shared by multiple subspaces provided each one has a unique platform
interrupt ack preserve and ack set masks.

If it can be shared, then we can request the irq with IRQF_SHARED and
IRQF_ONESHOT flags. The first one indicating it can be shared and the
latter one to keep the interrupt disabled until the hardirq handler
finished.

Further, since there is no way to detect if the interrupt is for a given
channel as the interrupt ack preserve and ack set masks are for clearing
the interrupt and not for reading the status(in case Irq Ack register
may be write-only on some platforms), we need a way to identify if the
given channel is in use and expecting the interrupt.

PCC type0, type1 and type5 do not support shared level triggered interrupt.
The methods of determining whether a given channel for remaining types
should respond to an interrupt are as follows:
 - type2: Whether the interrupt belongs to a given channel is only
          determined by the status field in Generic Communications Channel
          Shared Memory Region, which is done in rx_callback of PCC client.
 - type3: This channel checks chan_in_use flag first and then checks the
          command complete bit(value '1' indicates that the command has
          been completed).
 - type4: Platform ensure that the default value of the command complete
          bit corresponding to the type4 channel is '1'. This command
          complete bit is '0' when receive a platform notification.

The new field, 'chan_in_use' is used by the type only support the
communication from OSPM to Platform (like type3) and should be completely
ignored by other types so as to avoid too many type unnecessary checks in
IRQ handler.

Signed-off-by: Huisong Li <lihuisong@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/20230801063827.25336-3-lihuisong@huawei.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2023-09-11 10:31:17 +01:00

834 lines
22 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2014 Linaro Ltd.
* Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
*
* 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 succeeded 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/log2.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"
/**
* struct pcc_chan_reg - PCC register bundle
*
* @vaddr: cached virtual address for this register
* @gas: pointer to the generic address structure for this register
* @preserve_mask: bitmask to preserve when writing to this register
* @set_mask: bitmask to set when writing to this register
* @status_mask: bitmask to determine and/or update the status for this register
*/
struct pcc_chan_reg {
void __iomem *vaddr;
struct acpi_generic_address *gas;
u64 preserve_mask;
u64 set_mask;
u64 status_mask;
};
/**
* struct pcc_chan_info - PCC channel specific information
*
* @chan: PCC channel information with Shared Memory Region info
* @db: PCC register bundle for the doorbell register
* @plat_irq_ack: PCC register bundle for the platform interrupt acknowledge
* register
* @cmd_complete: PCC register bundle for the command complete check register
* @cmd_update: PCC register bundle for the command complete update register
* @error: PCC register bundle for the error status register
* @plat_irq: platform interrupt
* @type: PCC subspace type
* @plat_irq_flags: platform interrupt flags
* @chan_in_use: this flag is used just to check if the interrupt needs
* handling when it is shared. Since only one transfer can occur
* at a time and mailbox takes care of locking, this flag can be
* accessed without a lock. Note: the type only support the
* communication from OSPM to Platform, like type3, use it, and
* other types completely ignore it.
*/
struct pcc_chan_info {
struct pcc_mbox_chan chan;
struct pcc_chan_reg db;
struct pcc_chan_reg plat_irq_ack;
struct pcc_chan_reg cmd_complete;
struct pcc_chan_reg cmd_update;
struct pcc_chan_reg error;
int plat_irq;
u8 type;
unsigned int plat_irq_flags;
bool chan_in_use;
};
#define to_pcc_chan_info(c) container_of(c, struct pcc_chan_info, chan)
static struct pcc_chan_info *chan_info;
static int pcc_chan_count;
static int pcc_send_data(struct mbox_chan *chan, void *data);
/*
* 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 void read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width)
{
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;
}
}
static void write_register(void __iomem *vaddr, u64 val, unsigned int bit_width)
{
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;
}
}
static int pcc_chan_reg_read(struct pcc_chan_reg *reg, u64 *val)
{
int ret = 0;
if (!reg->gas) {
*val = 0;
return 0;
}
if (reg->vaddr)
read_register(reg->vaddr, val, reg->gas->bit_width);
else
ret = acpi_read(val, reg->gas);
return ret;
}
static int pcc_chan_reg_write(struct pcc_chan_reg *reg, u64 val)
{
int ret = 0;
if (!reg->gas)
return 0;
if (reg->vaddr)
write_register(reg->vaddr, val, reg->gas->bit_width);
else
ret = acpi_write(val, reg->gas);
return ret;
}
static int pcc_chan_reg_read_modify_write(struct pcc_chan_reg *reg)
{
int ret = 0;
u64 val;
ret = pcc_chan_reg_read(reg, &val);
if (ret)
return ret;
val &= reg->preserve_mask;
val |= reg->set_mask;
return pcc_chan_reg_write(reg, 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);
}
static bool pcc_chan_plat_irq_can_be_shared(struct pcc_chan_info *pchan)
{
return (pchan->plat_irq_flags & ACPI_PCCT_INTERRUPT_MODE) ==
ACPI_LEVEL_SENSITIVE;
}
static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan)
{
u64 val;
int ret;
ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
if (ret)
return false;
if (!pchan->cmd_complete.gas)
return true;
/*
* Judge if the channel respond the interrupt based on the value of
* command complete.
*/
val &= pchan->cmd_complete.status_mask;
/*
* If this is PCC slave subspace channel, and the command complete
* bit 0 indicates that Platform is sending a notification and OSPM
* needs to respond this interrupt to process this command.
*/
if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
return !val;
return !!val;
}
/**
* pcc_mbox_irq - PCC mailbox interrupt handler
* @irq: interrupt number
* @p: data/cookie passed from the caller to identify the channel
*
* Returns: IRQ_HANDLED if interrupt is handled or IRQ_NONE if not
*/
static irqreturn_t pcc_mbox_irq(int irq, void *p)
{
struct pcc_chan_info *pchan;
struct mbox_chan *chan = p;
u64 val;
int ret;
pchan = chan->con_priv;
if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE &&
!pchan->chan_in_use)
return IRQ_NONE;
if (!pcc_mbox_cmd_complete_check(pchan))
return IRQ_NONE;
ret = pcc_chan_reg_read(&pchan->error, &val);
if (ret)
return IRQ_NONE;
val &= pchan->error.status_mask;
if (val) {
val &= ~pchan->error.status_mask;
pcc_chan_reg_write(&pchan->error, val);
return IRQ_NONE;
}
if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack))
return IRQ_NONE;
mbox_chan_received_data(chan, NULL);
/*
* The PCC slave subspace channel needs to set the command complete bit
* and ring doorbell after processing message.
*
* The PCC master subspace channel clears chan_in_use to free channel.
*/
if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
pcc_send_data(chan, NULL);
pchan->chan_in_use = false;
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 PCC Mailbox Channel if successful or ERR_PTR.
*/
struct pcc_mbox_chan *
pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
{
struct pcc_chan_info *pchan;
struct mbox_chan *chan;
int rc;
if (subspace_id < 0 || subspace_id >= pcc_chan_count)
return ERR_PTR(-ENOENT);
pchan = chan_info + subspace_id;
chan = pchan->chan.mchan;
if (IS_ERR(chan) || chan->cl) {
pr_err("Channel not found for idx: %d\n", subspace_id);
return ERR_PTR(-EBUSY);
}
rc = mbox_bind_client(chan, cl);
if (rc)
return ERR_PTR(rc);
return &pchan->chan;
}
EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
/**
* pcc_mbox_free_channel - Clients call this to free their Channel.
*
* @pchan: Pointer to the PCC mailbox channel as returned by
* pcc_mbox_request_channel()
*/
void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan)
{
struct mbox_chan *chan = pchan->mchan;
if (!chan || !chan->cl)
return;
mbox_free_channel(chan);
}
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)
{
int ret;
struct pcc_chan_info *pchan = chan->con_priv;
ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update);
if (ret)
return ret;
ret = pcc_chan_reg_read_modify_write(&pchan->db);
if (!ret && pchan->plat_irq > 0)
pchan->chan_in_use = true;
return ret;
}
/**
* pcc_startup - Called from Mailbox Controller code. Used here
* to request the interrupt.
* @chan: Pointer to Mailbox channel to startup.
*
* Return: Err if something failed else 0 for success.
*/
static int pcc_startup(struct mbox_chan *chan)
{
struct pcc_chan_info *pchan = chan->con_priv;
unsigned long irqflags;
int rc;
if (pchan->plat_irq > 0) {
irqflags = pcc_chan_plat_irq_can_be_shared(pchan) ?
IRQF_SHARED | IRQF_ONESHOT : 0;
rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq,
irqflags, MBOX_IRQ_NAME, chan);
if (unlikely(rc)) {
dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n",
pchan->plat_irq);
return rc;
}
}
return 0;
}
/**
* pcc_shutdown - Called from Mailbox Controller code. Used here
* to free the interrupt.
* @chan: Pointer to Mailbox channel to shutdown.
*/
static void pcc_shutdown(struct mbox_chan *chan)
{
struct pcc_chan_info *pchan = chan->con_priv;
if (pchan->plat_irq > 0)
devm_free_irq(chan->mbox->dev, pchan->plat_irq, chan);
}
static const struct mbox_chan_ops pcc_chan_ops = {
.send_data = pcc_send_data,
.startup = pcc_startup,
.shutdown = pcc_shutdown,
};
/**
* parse_pcc_subspace - 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;
}
static int
pcc_chan_reg_init(struct pcc_chan_reg *reg, struct acpi_generic_address *gas,
u64 preserve_mask, u64 set_mask, u64 status_mask, char *name)
{
if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
if (!(gas->bit_width >= 8 && gas->bit_width <= 64 &&
is_power_of_2(gas->bit_width))) {
pr_err("Error: Cannot access register of %u bit width",
gas->bit_width);
return -EFAULT;
}
reg->vaddr = acpi_os_ioremap(gas->address, gas->bit_width / 8);
if (!reg->vaddr) {
pr_err("Failed to ioremap PCC %s register\n", name);
return -ENOMEM;
}
}
reg->gas = gas;
reg->preserve_mask = preserve_mask;
reg->set_mask = set_mask;
reg->status_mask = status_mask;
return 0;
}
/**
* pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register
*
* @pchan: Pointer to the PCC channel info structure.
* @pcct_entry: Pointer to the ACPI subtable header.
*
* Return: 0 for Success, else errno.
*
* There should be one entry per PCC channel. This gets called for each
* entry in the PCC table. This uses PCCY Type1 structure for all applicable
* types(Type 1-4) to fetch irq
*/
static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan,
struct acpi_subtable_header *pcct_entry)
{
int ret = 0;
struct acpi_pcct_hw_reduced *pcct_ss;
if (pcct_entry->type < ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE ||
pcct_entry->type > ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
return 0;
pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry;
pchan->plat_irq = pcc_map_interrupt(pcct_ss->platform_interrupt,
(u32)pcct_ss->flags);
if (pchan->plat_irq <= 0) {
pr_err("PCC GSI %d not registered\n",
pcct_ss->platform_interrupt);
return -EINVAL;
}
pchan->plat_irq_flags = pcct_ss->flags;
if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss;
ret = pcc_chan_reg_init(&pchan->plat_irq_ack,
&pcct2_ss->platform_ack_register,
pcct2_ss->ack_preserve_mask,
pcct2_ss->ack_write_mask, 0,
"PLAT IRQ ACK");
} else if (pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE ||
pcct_ss->header.type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE) {
struct acpi_pcct_ext_pcc_master *pcct_ext = (void *)pcct_ss;
ret = pcc_chan_reg_init(&pchan->plat_irq_ack,
&pcct_ext->platform_ack_register,
pcct_ext->ack_preserve_mask,
pcct_ext->ack_set_mask, 0,
"PLAT IRQ ACK");
}
if (pcc_chan_plat_irq_can_be_shared(pchan) &&
!pchan->plat_irq_ack.gas) {
pr_err("PCC subspace has level IRQ with no ACK register\n");
return -EINVAL;
}
return ret;
}
/**
* pcc_parse_subspace_db_reg - Parse the PCC doorbell register
*
* @pchan: Pointer to the PCC channel info structure.
* @pcct_entry: Pointer to the ACPI subtable header.
*
* Return: 0 for Success, else errno.
*/
static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan,
struct acpi_subtable_header *pcct_entry)
{
int ret = 0;
if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
struct acpi_pcct_subspace *pcct_ss;
pcct_ss = (struct acpi_pcct_subspace *)pcct_entry;
ret = pcc_chan_reg_init(&pchan->db,
&pcct_ss->doorbell_register,
pcct_ss->preserve_mask,
pcct_ss->write_mask, 0, "Doorbell");
} else {
struct acpi_pcct_ext_pcc_master *pcct_ext;
pcct_ext = (struct acpi_pcct_ext_pcc_master *)pcct_entry;
ret = pcc_chan_reg_init(&pchan->db,
&pcct_ext->doorbell_register,
pcct_ext->preserve_mask,
pcct_ext->write_mask, 0, "Doorbell");
if (ret)
return ret;
ret = pcc_chan_reg_init(&pchan->cmd_complete,
&pcct_ext->cmd_complete_register,
0, 0, pcct_ext->cmd_complete_mask,
"Command Complete Check");
if (ret)
return ret;
ret = pcc_chan_reg_init(&pchan->cmd_update,
&pcct_ext->cmd_update_register,
pcct_ext->cmd_update_preserve_mask,
pcct_ext->cmd_update_set_mask, 0,
"Command Complete Update");
if (ret)
return ret;
ret = pcc_chan_reg_init(&pchan->error,
&pcct_ext->error_status_register,
0, 0, pcct_ext->error_status_mask,
"Error Status");
}
return ret;
}
/**
* pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information
*
* @pchan: Pointer to the PCC channel info structure.
* @pcct_entry: Pointer to the ACPI subtable header.
*
*/
static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan,
struct acpi_subtable_header *pcct_entry)
{
if (pcct_entry->type <= ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
struct acpi_pcct_subspace *pcct_ss =
(struct acpi_pcct_subspace *)pcct_entry;
pchan->chan.shmem_base_addr = pcct_ss->base_address;
pchan->chan.shmem_size = pcct_ss->length;
pchan->chan.latency = pcct_ss->latency;
pchan->chan.max_access_rate = pcct_ss->max_access_rate;
pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time;
} else {
struct acpi_pcct_ext_pcc_master *pcct_ext =
(struct acpi_pcct_ext_pcc_master *)pcct_entry;
pchan->chan.shmem_base_addr = pcct_ext->base_address;
pchan->chan.shmem_size = pcct_ext->length;
pchan->chan.latency = pcct_ext->latency;
pchan->chan.max_access_rate = pcct_ext->max_access_rate;
pchan->chan.min_turnaround_time = pcct_ext->min_turnaround_time;
}
}
/**
* acpi_pcc_probe - Parse the ACPI tree for the PCCT.
*
* Return: 0 for Success, else errno.
*/
static int __init acpi_pcc_probe(void)
{
int count, i, rc = 0;
acpi_status status;
struct acpi_table_header *pcct_tbl;
struct acpi_subtable_proc proc[ACPI_PCCT_TYPE_RESERVED];
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);
rc = -EINVAL;
} else {
pcc_chan_count = count;
}
acpi_put_table(pcct_tbl);
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)
{
struct device *dev = &pdev->dev;
struct mbox_controller *pcc_mbox_ctrl;
struct mbox_chan *pcc_mbox_channels;
struct acpi_table_header *pcct_tbl;
struct acpi_subtable_header *pcct_entry;
struct acpi_table_pcct *acpi_pcct_tbl;
acpi_status status = AE_OK;
int i, rc, count = pcc_chan_count;
/* Search for PCCT */
status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
if (ACPI_FAILURE(status) || !pcct_tbl)
return -ENODEV;
pcc_mbox_channels = devm_kcalloc(dev, count, sizeof(*pcc_mbox_channels),
GFP_KERNEL);
if (!pcc_mbox_channels) {
rc = -ENOMEM;
goto err;
}
chan_info = devm_kcalloc(dev, count, sizeof(*chan_info), GFP_KERNEL);
if (!chan_info) {
rc = -ENOMEM;
goto err;
}
pcc_mbox_ctrl = devm_kzalloc(dev, sizeof(*pcc_mbox_ctrl), GFP_KERNEL);
if (!pcc_mbox_ctrl) {
rc = -ENOMEM;
goto err;
}
/* 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 pcc_chan_info *pchan = chan_info + i;
pcc_mbox_channels[i].con_priv = pchan;
pchan->chan.mchan = &pcc_mbox_channels[i];
if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE &&
!pcc_mbox_ctrl->txdone_irq) {
pr_err("Platform Interrupt flag must be set to 1");
rc = -EINVAL;
goto err;
}
if (pcc_mbox_ctrl->txdone_irq) {
rc = pcc_parse_subspace_irq(pchan, pcct_entry);
if (rc < 0)
goto err;
}
rc = pcc_parse_subspace_db_reg(pchan, pcct_entry);
if (rc < 0)
goto err;
pcc_parse_subspace_shmem(pchan, pcct_entry);
pchan->type = pcct_entry->type;
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);
pcc_mbox_ctrl->chans = pcc_mbox_channels;
pcc_mbox_ctrl->ops = &pcc_chan_ops;
pcc_mbox_ctrl->dev = dev;
pr_info("Registering PCC driver as Mailbox controller\n");
rc = mbox_controller_register(pcc_mbox_ctrl);
if (rc)
pr_err("Err registering PCC as Mailbox controller: %d\n", rc);
else
return 0;
err:
acpi_put_table(pcct_tbl);
return rc;
}
static struct platform_driver pcc_mbox_driver = {
.probe = pcc_mbox_probe,
.driver = {
.name = "PCCT",
},
};
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");
pcc_chan_count = 0;
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);