From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/mailbox/pcc.c | 758 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 758 insertions(+) create mode 100644 drivers/mailbox/pcc.c (limited to 'drivers/mailbox/pcc.c') diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c new file mode 100644 index 000000000..105d46c98 --- /dev/null +++ b/drivers/mailbox/pcc.c @@ -0,0 +1,758 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2014 Linaro Ltd. + * Author: Ashwin Chaugule + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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 + */ +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; +}; + +#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; + +/* + * 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); +} + +/** + * 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; + + ret = pcc_chan_reg_read(&pchan->cmd_complete, &val); + if (ret) + return IRQ_NONE; + + if (val) { /* Ensure GAS exists and value is non-zero */ + val &= pchan->cmd_complete.status_mask; + if (!val) + 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); + + 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; + struct device *dev; + unsigned long flags; + + 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); + } + dev = chan->mbox->dev; + + 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 (pchan->plat_irq > 0) { + int rc; + + rc = devm_request_irq(dev, pchan->plat_irq, pcc_mbox_irq, 0, + MBOX_IRQ_NAME, chan); + if (unlikely(rc)) { + dev_err(dev, "failed to register PCC interrupt %d\n", + pchan->plat_irq); + pcc_mbox_free_channel(&pchan->chan); + 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 pcc_chan_info *pchan_info = to_pcc_chan_info(pchan); + struct mbox_chan *chan = pchan->mchan; + unsigned long flags; + + if (!chan || !chan->cl) + return; + + if (pchan_info->plat_irq > 0) + devm_free_irq(chan->mbox->dev, pchan_info->plat_irq, 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) +{ + int ret; + struct pcc_chan_info *pchan = chan->con_priv; + + ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update); + if (ret) + return ret; + + return pcc_chan_reg_read_modify_write(&pchan->db); +} + +static const struct mbox_chan_ops pcc_chan_ops = { + .send_data = pcc_send_data, +}; + +/** + * 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; + } + + 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"); + } + + 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); + + 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); -- cgit v1.2.3