Pull mailbox framework updates from Jassi Brar. * 'mailbox-devel' of git://git.linaro.org/landing-teams/working/fujitsu/integration: Mailbox: Add support for Platform Communication Channel mailbox/omap: adapt to the new mailbox framework mailbox: add tx_prepare client callback mailbox: Don't unnecessarily re-arm the polling timertirimbino
Linus Torvalds
10 years ago
commit
14ba9a2e4b
@ -0,0 +1,14 @@ |
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/*
|
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License version 2 as |
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* published by the Free Software Foundation. |
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*/ |
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|
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#ifndef __MAILBOX_H |
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#define __MAILBOX_H |
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#define TXDONE_BY_IRQ BIT(0) /* controller has remote RTR irq */ |
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#define TXDONE_BY_POLL BIT(1) /* controller can read status of last TX */ |
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#define TXDONE_BY_ACK BIT(2) /* S/W ACK recevied by Client ticks the TX */ |
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#endif /* __MAILBOX_H */ |
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@ -0,0 +1,403 @@ |
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/*
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* Copyright (C) 2014 Linaro Ltd. |
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* Author: Ashwin Chaugule <ashwin.chaugule@linaro.org> |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* PCC (Platform Communication Channel) is defined in the ACPI 5.0+ |
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* specification. It is a mailbox like mechanism to allow clients |
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* such as CPPC (Collaborative Processor Performance Control), RAS |
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* (Reliability, Availability and Serviceability) and MPST (Memory |
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* Node Power State Table) to talk to the platform (e.g. BMC) through |
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* shared memory regions as defined in the PCC table entries. The PCC |
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* specification supports a Doorbell mechanism for the PCC clients |
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* to notify the platform about new data. This Doorbell information |
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* is also specified in each PCC table entry. See pcc_send_data() |
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* and pcc_tx_done() for basic mode of operation. |
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* |
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* For more details about PCC, please see the ACPI specification from |
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* http://www.uefi.org/ACPIv5.1 Section 14.
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* |
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* This file implements PCC as a Mailbox controller and allows for PCC |
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* clients to be implemented as its Mailbox Client Channels. |
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*/ |
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#include <linux/acpi.h> |
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#include <linux/delay.h> |
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#include <linux/io.h> |
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#include <linux/init.h> |
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#include <linux/list.h> |
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#include <linux/platform_device.h> |
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#include <linux/mailbox_controller.h> |
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#include <linux/mailbox_client.h> |
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#include "mailbox.h" |
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#define MAX_PCC_SUBSPACES 256 |
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#define PCCS_SS_SIG_MAGIC 0x50434300 |
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#define PCC_CMD_COMPLETE 0x1 |
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static struct mbox_chan *pcc_mbox_channels; |
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static struct mbox_controller pcc_mbox_ctrl = {}; |
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/**
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* get_pcc_channel - Given a PCC subspace idx, get |
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* the respective mbox_channel. |
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* @id: PCC subspace index. |
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* |
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* Return: ERR_PTR(errno) if error, else pointer |
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* to mbox channel. |
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*/ |
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static struct mbox_chan *get_pcc_channel(int id) |
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{ |
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struct mbox_chan *pcc_chan; |
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if (id < 0 || id > pcc_mbox_ctrl.num_chans) |
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return ERR_PTR(-ENOENT); |
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pcc_chan = (struct mbox_chan *) |
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(unsigned long) pcc_mbox_channels + |
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(id * sizeof(*pcc_chan)); |
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return pcc_chan; |
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} |
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/**
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* get_subspace_id - Given a Mailbox channel, find out the |
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* PCC subspace id. |
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* @chan: Pointer to Mailbox Channel from which we want |
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* the index. |
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* Return: Errno if not found, else positive index number. |
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*/ |
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static int get_subspace_id(struct mbox_chan *chan) |
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{ |
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unsigned int id = chan - pcc_mbox_channels; |
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if (id < 0 || id > pcc_mbox_ctrl.num_chans) |
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return -ENOENT; |
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return id; |
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} |
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/**
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* pcc_mbox_request_channel - PCC clients call this function to |
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* request a pointer to their PCC subspace, from which they |
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* can get the details of communicating with the remote. |
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* @cl: Pointer to Mailbox client, so we know where to bind the |
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* Channel. |
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* @subspace_id: The PCC Subspace index as parsed in the PCC client |
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* ACPI package. This is used to lookup the array of PCC |
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* subspaces as parsed by the PCC Mailbox controller. |
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* |
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* Return: Pointer to the Mailbox Channel if successful or |
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* ERR_PTR. |
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*/ |
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struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl, |
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int subspace_id) |
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{ |
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struct device *dev = pcc_mbox_ctrl.dev; |
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struct mbox_chan *chan; |
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unsigned long flags; |
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/*
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* Each PCC Subspace is a Mailbox Channel. |
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* The PCC Clients get their PCC Subspace ID |
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* from their own tables and pass it here. |
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* This returns a pointer to the PCC subspace |
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* for the Client to operate on. |
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*/ |
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chan = get_pcc_channel(subspace_id); |
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if (!chan || chan->cl) { |
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dev_err(dev, "%s: PCC mailbox not free\n", __func__); |
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return ERR_PTR(-EBUSY); |
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} |
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spin_lock_irqsave(&chan->lock, flags); |
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chan->msg_free = 0; |
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chan->msg_count = 0; |
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chan->active_req = NULL; |
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chan->cl = cl; |
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init_completion(&chan->tx_complete); |
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if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone) |
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chan->txdone_method |= TXDONE_BY_ACK; |
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spin_unlock_irqrestore(&chan->lock, flags); |
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return chan; |
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} |
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EXPORT_SYMBOL_GPL(pcc_mbox_request_channel); |
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/**
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* pcc_mbox_free_channel - Clients call this to free their Channel. |
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* |
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* @chan: Pointer to the mailbox channel as returned by |
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* pcc_mbox_request_channel() |
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*/ |
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void pcc_mbox_free_channel(struct mbox_chan *chan) |
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{ |
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unsigned long flags; |
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if (!chan || !chan->cl) |
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return; |
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spin_lock_irqsave(&chan->lock, flags); |
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chan->cl = NULL; |
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chan->active_req = NULL; |
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if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK)) |
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chan->txdone_method = TXDONE_BY_POLL; |
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spin_unlock_irqrestore(&chan->lock, flags); |
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} |
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EXPORT_SYMBOL_GPL(pcc_mbox_free_channel); |
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/**
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* pcc_tx_done - Callback from Mailbox controller code to |
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* check if PCC message transmission completed. |
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* @chan: Pointer to Mailbox channel on which previous |
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* transmission occurred. |
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* |
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* Return: TRUE if succeeded. |
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*/ |
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static bool pcc_tx_done(struct mbox_chan *chan) |
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{ |
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struct acpi_pcct_hw_reduced *pcct_ss = chan->con_priv; |
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struct acpi_pcct_shared_memory *generic_comm_base = |
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(struct acpi_pcct_shared_memory *) pcct_ss->base_address; |
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u16 cmd_delay = pcct_ss->latency; |
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unsigned int retries = 0; |
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/* Try a few times while waiting for platform to consume */ |
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while (!(readw_relaxed(&generic_comm_base->status) |
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& PCC_CMD_COMPLETE)) { |
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if (retries++ < 5) |
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udelay(cmd_delay); |
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else { |
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/*
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* If the remote is dead, this will cause the Mbox |
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* controller to timeout after mbox client.tx_tout |
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* msecs. |
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*/ |
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pr_err("PCC platform did not respond.\n"); |
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return false; |
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} |
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} |
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return true; |
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} |
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/**
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* pcc_send_data - Called from Mailbox Controller code to finally |
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* transmit data over channel. |
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* @chan: Pointer to Mailbox channel over which to send data. |
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* @data: Actual data to be written over channel. |
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* |
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* Return: Err if something failed else 0 for success. |
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*/ |
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static int pcc_send_data(struct mbox_chan *chan, void *data) |
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{ |
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struct acpi_pcct_hw_reduced *pcct_ss = chan->con_priv; |
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struct acpi_pcct_shared_memory *generic_comm_base = |
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(struct acpi_pcct_shared_memory *) pcct_ss->base_address; |
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struct acpi_generic_address doorbell; |
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u64 doorbell_preserve; |
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u64 doorbell_val; |
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u64 doorbell_write; |
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u16 cmd = *(u16 *) data; |
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u16 ss_idx = -1; |
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ss_idx = get_subspace_id(chan); |
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if (ss_idx < 0) { |
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pr_err("Invalid Subspace ID from PCC client\n"); |
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return -EINVAL; |
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} |
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doorbell = pcct_ss->doorbell_register; |
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doorbell_preserve = pcct_ss->preserve_mask; |
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doorbell_write = pcct_ss->write_mask; |
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/* Write to the shared comm region. */ |
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writew(cmd, &generic_comm_base->command); |
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/* Write Subspace MAGIC value so platform can identify destination. */ |
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writel((PCCS_SS_SIG_MAGIC | ss_idx), &generic_comm_base->signature); |
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/* Flip CMD COMPLETE bit */ |
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writew(0, &generic_comm_base->status); |
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/* Sync notification from OSPM to Platform. */ |
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acpi_read(&doorbell_val, &doorbell); |
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acpi_write((doorbell_val & doorbell_preserve) | doorbell_write, |
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&doorbell); |
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return 0; |
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} |
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static struct mbox_chan_ops pcc_chan_ops = { |
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.send_data = pcc_send_data, |
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.last_tx_done = pcc_tx_done, |
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}; |
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/**
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* parse_pcc_subspace - Parse the PCC table and verify PCC subspace |
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* entries. There should be one entry per PCC client. |
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* @header: Pointer to the ACPI subtable header under the PCCT. |
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* @end: End of subtable entry. |
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* |
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* Return: 0 for Success, else errno. |
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* |
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* This gets called for each entry in the PCC table. |
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*/ |
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static int parse_pcc_subspace(struct acpi_subtable_header *header, |
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const unsigned long end) |
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{ |
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struct acpi_pcct_hw_reduced *pcct_ss; |
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if (pcc_mbox_ctrl.num_chans <= MAX_PCC_SUBSPACES) { |
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pcct_ss = (struct acpi_pcct_hw_reduced *) header; |
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if (pcct_ss->header.type != |
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ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE) { |
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pr_err("Incorrect PCC Subspace type detected\n"); |
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return -EINVAL; |
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} |
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} |
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return 0; |
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} |
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/**
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* acpi_pcc_probe - Parse the ACPI tree for the PCCT. |
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* |
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* Return: 0 for Success, else errno. |
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*/ |
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static int __init acpi_pcc_probe(void) |
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{ |
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acpi_size pcct_tbl_header_size; |
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struct acpi_table_header *pcct_tbl; |
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struct acpi_subtable_header *pcct_entry; |
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int count, i; |
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acpi_status status = AE_OK; |
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/* Search for PCCT */ |
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status = acpi_get_table_with_size(ACPI_SIG_PCCT, 0, |
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&pcct_tbl, |
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&pcct_tbl_header_size); |
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if (ACPI_FAILURE(status) || !pcct_tbl) { |
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pr_warn("PCCT header not found.\n"); |
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return -ENODEV; |
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} |
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count = acpi_table_parse_entries(ACPI_SIG_PCCT, |
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sizeof(struct acpi_table_pcct), |
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ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE, |
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parse_pcc_subspace, MAX_PCC_SUBSPACES); |
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if (count <= 0) { |
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pr_err("Error parsing PCC subspaces from PCCT\n"); |
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return -EINVAL; |
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} |
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pcc_mbox_channels = kzalloc(sizeof(struct mbox_chan) * |
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count, GFP_KERNEL); |
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if (!pcc_mbox_channels) { |
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pr_err("Could not allocate space for PCC mbox channels\n"); |
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return -ENOMEM; |
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} |
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/* Point to the first PCC subspace entry */ |
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pcct_entry = (struct acpi_subtable_header *) ( |
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(unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct)); |
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for (i = 0; i < count; i++) { |
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pcc_mbox_channels[i].con_priv = pcct_entry; |
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pcct_entry = (struct acpi_subtable_header *) |
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((unsigned long) pcct_entry + pcct_entry->length); |
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} |
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pcc_mbox_ctrl.num_chans = count; |
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pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl.num_chans); |
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return 0; |
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} |
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/**
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* pcc_mbox_probe - Called when we find a match for the |
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* PCCT platform device. This is purely used to represent |
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* the PCCT as a virtual device for registering with the |
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* generic Mailbox framework. |
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* |
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* @pdev: Pointer to platform device returned when a match |
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* is found. |
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* |
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* Return: 0 for Success, else errno. |
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*/ |
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static int pcc_mbox_probe(struct platform_device *pdev) |
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{ |
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int ret = 0; |
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pcc_mbox_ctrl.chans = pcc_mbox_channels; |
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pcc_mbox_ctrl.ops = &pcc_chan_ops; |
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pcc_mbox_ctrl.txdone_poll = true; |
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pcc_mbox_ctrl.txpoll_period = 10; |
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pcc_mbox_ctrl.dev = &pdev->dev; |
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pr_info("Registering PCC driver as Mailbox controller\n"); |
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ret = mbox_controller_register(&pcc_mbox_ctrl); |
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if (ret) { |
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pr_err("Err registering PCC as Mailbox controller: %d\n", ret); |
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ret = -ENODEV; |
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} |
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return ret; |
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} |
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struct platform_driver pcc_mbox_driver = { |
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.probe = pcc_mbox_probe, |
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.driver = { |
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.name = "PCCT", |
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.owner = THIS_MODULE, |
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}, |
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}; |
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static int __init pcc_init(void) |
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{ |
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int ret; |
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struct platform_device *pcc_pdev; |
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if (acpi_disabled) |
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return -ENODEV; |
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/* Check if PCC support is available. */ |
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ret = acpi_pcc_probe(); |
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if (ret) { |
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pr_err("ACPI PCC probe failed.\n"); |
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return -ENODEV; |
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} |
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pcc_pdev = platform_create_bundle(&pcc_mbox_driver, |
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pcc_mbox_probe, NULL, 0, NULL, 0); |
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if (!pcc_pdev) { |
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pr_err("Err creating PCC platform bundle\n"); |
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return -ENODEV; |
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} |
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return 0; |
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} |
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device_initcall(pcc_init); |
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