diff options
Diffstat (limited to 'drivers/mailbox')
| -rw-r--r-- | drivers/mailbox/Kconfig | 12 | ||||
| -rw-r--r-- | drivers/mailbox/Makefile | 2 | ||||
| -rw-r--r-- | drivers/mailbox/mailbox.c | 4 | ||||
| -rw-r--r-- | drivers/mailbox/mailbox.h | 14 | ||||
| -rw-r--r-- | drivers/mailbox/pcc.c | 403 |
5 files changed, 432 insertions, 3 deletions
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig index 9fd9c6717e0c..c04fed9eb15d 100644 --- a/drivers/mailbox/Kconfig +++ b/drivers/mailbox/Kconfig @@ -33,4 +33,16 @@ config OMAP_MBOX_KFIFO_SIZE Specify the default size of mailbox's kfifo buffers (bytes). This can also be changed at runtime (via the mbox_kfifo_size module parameter). + +config PCC + bool "Platform Communication Channel Driver" + depends on ACPI + help + ACPI 5.0+ spec defines a generic mode of communication + between the OS and a platform such as the BMC. This medium + (PCC) is typically used by CPPC (ACPI CPU Performance management), + RAS (ACPI reliability protocol) and MPST (ACPI Memory power + states). Select this driver if your platform implements the + PCC clients mentioned above. + endif diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile index 94ed7cefb14d..dd412c22208b 100644 --- a/drivers/mailbox/Makefile +++ b/drivers/mailbox/Makefile @@ -5,3 +5,5 @@ obj-$(CONFIG_MAILBOX) += mailbox.o obj-$(CONFIG_PL320_MBOX) += pl320-ipc.o obj-$(CONFIG_OMAP2PLUS_MBOX) += omap-mailbox.o + +obj-$(CONFIG_PCC) += pcc.o diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c index 58789b027708..59aad4d5da53 100644 --- a/drivers/mailbox/mailbox.c +++ b/drivers/mailbox/mailbox.c @@ -21,9 +21,7 @@ #include <linux/mailbox_client.h> #include <linux/mailbox_controller.h> -#define TXDONE_BY_IRQ BIT(0) /* controller has remote RTR irq */ -#define TXDONE_BY_POLL BIT(1) /* controller can read status of last TX */ -#define TXDONE_BY_ACK BIT(2) /* S/W ACK recevied by Client ticks the TX */ +#include "mailbox.h" static LIST_HEAD(mbox_cons); static DEFINE_MUTEX(con_mutex); diff --git a/drivers/mailbox/mailbox.h b/drivers/mailbox/mailbox.h new file mode 100644 index 000000000000..456ba68513bb --- /dev/null +++ b/drivers/mailbox/mailbox.h @@ -0,0 +1,14 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __MAILBOX_H +#define __MAILBOX_H + +#define TXDONE_BY_IRQ BIT(0) /* controller has remote RTR irq */ +#define TXDONE_BY_POLL BIT(1) /* controller can read status of last TX */ +#define TXDONE_BY_ACK BIT(2) /* S/W ACK recevied by Client ticks the TX */ + +#endif /* __MAILBOX_H */ diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c new file mode 100644 index 000000000000..6dbf6fcbdfaf --- /dev/null +++ b/drivers/mailbox/pcc.c @@ -0,0 +1,403 @@ +/* + * 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. See pcc_send_data() + * and pcc_tx_done() for basic mode of operation. + * + * 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/list.h> +#include <linux/platform_device.h> +#include <linux/mailbox_controller.h> +#include <linux/mailbox_client.h> + +#include "mailbox.h" + +#define MAX_PCC_SUBSPACES 256 +#define PCCS_SS_SIG_MAGIC 0x50434300 +#define PCC_CMD_COMPLETE 0x1 + +static struct mbox_chan *pcc_mbox_channels; + +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) +{ + struct mbox_chan *pcc_chan; + + if (id < 0 || id > pcc_mbox_ctrl.num_chans) + return ERR_PTR(-ENOENT); + + pcc_chan = (struct mbox_chan *) + (unsigned long) pcc_mbox_channels + + (id * sizeof(*pcc_chan)); + + return pcc_chan; +} + +/** + * get_subspace_id - Given a Mailbox channel, find out the + * PCC subspace id. + * @chan: Pointer to Mailbox Channel from which we want + * the index. + * Return: Errno if not found, else positive index number. + */ +static int get_subspace_id(struct mbox_chan *chan) +{ + unsigned int id = chan - pcc_mbox_channels; + + if (id < 0 || id > pcc_mbox_ctrl.num_chans) + return -ENOENT; + + return id; +} + +/** + * 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 (!chan || chan->cl) { + dev_err(dev, "%s: PCC mailbox not free\n", __func__); + 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); + + 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) +{ + unsigned long flags; + + if (!chan || !chan->cl) + return; + + spin_lock_irqsave(&chan->lock, flags); + chan->cl = NULL; + chan->active_req = NULL; + if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK)) + chan->txdone_method = TXDONE_BY_POLL; + + spin_unlock_irqrestore(&chan->lock, flags); +} +EXPORT_SYMBOL_GPL(pcc_mbox_free_channel); + +/** + * pcc_tx_done - Callback from Mailbox controller code to + * check if PCC message transmission completed. + * @chan: Pointer to Mailbox channel on which previous + * transmission occurred. + * + * Return: TRUE if succeeded. + */ +static bool pcc_tx_done(struct mbox_chan *chan) +{ + struct acpi_pcct_hw_reduced *pcct_ss = chan->con_priv; + struct acpi_pcct_shared_memory *generic_comm_base = + (struct acpi_pcct_shared_memory *) pcct_ss->base_address; + u16 cmd_delay = pcct_ss->latency; + unsigned int retries = 0; + + /* Try a few times while waiting for platform to consume */ + while (!(readw_relaxed(&generic_comm_base->status) + & PCC_CMD_COMPLETE)) { + + if (retries++ < 5) + udelay(cmd_delay); + else { + /* + * If the remote is dead, this will cause the Mbox + * controller to timeout after mbox client.tx_tout + * msecs. + */ + pr_err("PCC platform did not respond.\n"); + return false; + } + } + return true; +} + +/** + * pcc_send_data - Called from Mailbox Controller code to finally + * transmit data over channel. + * @chan: Pointer to Mailbox channel over which to send data. + * @data: Actual data to be written over channel. + * + * 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_pcct_shared_memory *generic_comm_base = + (struct acpi_pcct_shared_memory *) pcct_ss->base_address; + struct acpi_generic_address doorbell; + u64 doorbell_preserve; + u64 doorbell_val; + u64 doorbell_write; + u16 cmd = *(u16 *) data; + u16 ss_idx = -1; + + ss_idx = get_subspace_id(chan); + + if (ss_idx < 0) { + pr_err("Invalid Subspace ID from PCC client\n"); + return -EINVAL; + } + + doorbell = pcct_ss->doorbell_register; + doorbell_preserve = pcct_ss->preserve_mask; + doorbell_write = pcct_ss->write_mask; + + /* Write to the shared comm region. */ + writew(cmd, &generic_comm_base->command); + + /* Write Subspace MAGIC value so platform can identify destination. */ + writel((PCCS_SS_SIG_MAGIC | ss_idx), &generic_comm_base->signature); + + /* Flip CMD COMPLETE bit */ + writew(0, &generic_comm_base->status); + + /* Sync notification from OSPM to Platform. */ + acpi_read(&doorbell_val, &doorbell); + acpi_write((doorbell_val & doorbell_preserve) | doorbell_write, + &doorbell); + + return 0; +} + +static struct mbox_chan_ops pcc_chan_ops = { + .send_data = pcc_send_data, + .last_tx_done = pcc_tx_done, +}; + +/** + * parse_pcc_subspace - Parse the PCC table and verify PCC subspace + * entries. There should be one entry per PCC client. + * @header: Pointer to the ACPI subtable header under the PCCT. + * @end: End of subtable entry. + * + * Return: 0 for Success, else errno. + * + * This gets called for each entry in the PCC table. + */ +static int parse_pcc_subspace(struct acpi_subtable_header *header, + const unsigned long end) +{ + struct acpi_pcct_hw_reduced *pcct_ss; + + if (pcc_mbox_ctrl.num_chans <= MAX_PCC_SUBSPACES) { + pcct_ss = (struct acpi_pcct_hw_reduced *) header; + + if (pcct_ss->header.type != + ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE) { + pr_err("Incorrect PCC Subspace type detected\n"); + return -EINVAL; + } + } + + 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) +{ + acpi_size pcct_tbl_header_size; + struct acpi_table_header *pcct_tbl; + struct acpi_subtable_header *pcct_entry; + int count, i; + acpi_status status = AE_OK; + + /* Search for PCCT */ + status = acpi_get_table_with_size(ACPI_SIG_PCCT, 0, + &pcct_tbl, + &pcct_tbl_header_size); + + if (ACPI_FAILURE(status) || !pcct_tbl) { + pr_warn("PCCT header not found.\n"); + return -ENODEV; + } + + count = acpi_table_parse_entries(ACPI_SIG_PCCT, + sizeof(struct acpi_table_pcct), + ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE, + parse_pcc_subspace, MAX_PCC_SUBSPACES); + + if (count <= 0) { + pr_err("Error parsing PCC subspaces from PCCT\n"); + return -EINVAL; + } + + pcc_mbox_channels = kzalloc(sizeof(struct mbox_chan) * + count, GFP_KERNEL); + + if (!pcc_mbox_channels) { + pr_err("Could not allocate space for PCC mbox channels\n"); + return -ENOMEM; + } + + /* Point to the first PCC subspace entry */ + pcct_entry = (struct acpi_subtable_header *) ( + (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct)); + + for (i = 0; i < count; i++) { + pcc_mbox_channels[i].con_priv = 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); + + return 0; +} + +/** + * 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.txdone_poll = true; + pcc_mbox_ctrl.txpoll_period = 10; + 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_err("ACPI PCC probe failed.\n"); + return -ENODEV; + } + + pcc_pdev = platform_create_bundle(&pcc_mbox_driver, + pcc_mbox_probe, NULL, 0, NULL, 0); + + if (!pcc_pdev) { + pr_err("Err creating PCC platform bundle\n"); + return -ENODEV; + } + + return 0; +} +device_initcall(pcc_init); |
