Hi, > From: linux-acpi-owner@xxxxxxxxxxxxxxx [mailto:linux-acpi-owner@xxxxxxxxxxxxxxx] On Behalf Of Ashwin Chaugule > Sent: Friday, September 05, 2014 2:49 AM > > 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). > > This patch adds PCC support as a Mailbox Controller. > > Signed-off-by: Ashwin Chaugule <ashwin.chaugule@xxxxxxxxxx> > --- > drivers/mailbox/Kconfig | 12 ++ > drivers/mailbox/Makefile | 2 + > drivers/mailbox/mailbox.c | 4 +- > drivers/mailbox/mailbox.h | 16 +++ > drivers/mailbox/pcc.c | 279 ++++++++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 310 insertions(+), 3 deletions(-) > create mode 100644 drivers/mailbox/mailbox.h > create mode 100644 drivers/mailbox/pcc.c > > diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig > index c8b5c13..e08cc83 100644 > --- a/drivers/mailbox/Kconfig > +++ b/drivers/mailbox/Kconfig > @@ -50,4 +50,16 @@ 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 2fa343a..0b09d6f 100644 > --- a/drivers/mailbox/Makefile > +++ b/drivers/mailbox/Makefile > @@ -9,3 +9,5 @@ obj-$(CONFIG_OMAP1_MBOX) += mailbox_omap1.o > mailbox_omap1-objs := mailbox-omap1.o > obj-$(CONFIG_OMAP2PLUS_MBOX) += mailbox_omap2.o > mailbox_omap2-objs := mailbox-omap2.o > + > +obj-$(CONFIG_PCC) += pcc.o > diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c > index 63ecc17..9d9366a 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 0000000..5a15a25 > --- /dev/null > +++ b/drivers/mailbox/mailbox.h > @@ -0,0 +1,16 @@ > +/* > + * 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 0000000..7831a01 > --- /dev/null > +++ b/drivers/mailbox/pcc.c > @@ -0,0 +1,279 @@ > +/* > + * Copyright (C) 2014 Linaro Ltd. > + * Author: Ashwin Chaugule <ashwin.chaugule@xxxxxxxxxx> > + * > + * 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. > + * > + */ > + > +#include <linux/acpi.h> > +#include <linux/cpufreq.h> > +#include <linux/delay.h> > +#include <linux/io.h> > +#include <linux/init.h> > +#include <linux/ioctl.h> > +#include <linux/module.h> > +#include <linux/uaccess.h> > +#include <linux/vmalloc.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_chan[MAX_PCC_SUBSPACES]; > +static struct mbox_controller pcc_mbox_ctrl = {}; > + > +struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl, > + int index) > +{ > + 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 = &pcc_mbox_chan[index]; > + > + 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) The tab should be a space here? > + chan->txdone_method |= TXDONE_BY_ACK; > + > + spin_unlock_irqrestore(&chan->lock, flags); > + > + return chan; > +} > +EXPORT_SYMBOL_GPL(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); > + > +static bool pcc_tx_done(struct mbox_chan *chan) > +{ > + struct acpi_pcct_subspace *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->min_turnaround_time; Should these parameters be acquired with chan-lock held? Is that possible to change them during runtime? > + > + /* Wait for Platform to consume. */ > + while (!(readw_relaxed(&generic_comm_base->status) & PCC_CMD_COMPLETE)) > + udelay(cmd_delay); > + > + return true; > +} > + > +static int get_subspace_id(struct mbox_chan *chan) > +{ > + int id = chan - pcc_mbox_chan; > + > + if (id < 0 || id > pcc_mbox_ctrl.num_chans) > + return -ENOENT; > + > + return id; > +} > + > +/* Channel lock is already held by mbox controller code. */ > +static int pcc_send_data(struct mbox_chan *chan, void *data) > +{ > + struct acpi_pcct_subspace *pcct_ss = chan->con_priv; > + struct acpi_pcct_shared_memory *generic_comm_base = > + (struct acpi_pcct_shared_memory *) pcct_ss->base_address; Ditto. > + struct acpi_generic_address doorbell; > + u64 doorbell_preserve; > + u64 doorbell_val; > + u64 doorbell_write; > + u16 cmd = *(u16 *) data; > + u16 ss_idx = -1; > + int ret = 0; > + > + ss_idx = get_subspace_id(chan); > + > + if (ss_idx < 0) { > + pr_err("Invalid Subspace ID from PCC client\n"); > + ret = -EINVAL; > + goto out_err; > + } > + > + 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); > + > +out_err: > + return ret; > +} > + > +static struct mbox_chan_ops pcc_chan_ops = { > + .send_data = pcc_send_data, > + .last_tx_done = pcc_tx_done, > +}; > + > +static int parse_pcc_subspace(struct acpi_subtable_header *header, > + const unsigned long end) > +{ > + struct acpi_pcct_subspace *pcct_ss; > + > + if (pcc_mbox_ctrl.num_chans <= MAX_PCC_SUBSPACES) { > + pcct_ss = (struct acpi_pcct_subspace *) header; > + > + if (pcct_ss->header.type != ACPI_PCCT_TYPE_GENERIC_SUBSPACE) { > + pr_err("Incorrect PCC Subspace type detected\n"); > + return -EINVAL; > + } > + > + /* New mbox channel entry for each PCC subspace detected. */ > + pcc_mbox_chan[pcc_mbox_ctrl.num_chans].con_priv = pcct_ss; > + pcc_mbox_ctrl.num_chans++; > + > + } else { > + pr_err("No more space for PCC subspaces.\n"); > + return -ENOSPC; > + } > + > + return 0; > +} > + > +static int __init acpi_pcc_probe(void) > +{ > + acpi_status status = AE_OK; > + acpi_size pcct_tbl_header_size; > + struct acpi_table_pcct *pcct_tbl; > + > + /* Search for PCCT */ > + status = acpi_get_table_with_size(ACPI_SIG_PCCT, 0, > + (struct acpi_table_header **)&pcct_tbl, > + &pcct_tbl_header_size); > + > + if (ACPI_SUCCESS(status) && !pcct_tbl) { > + pr_warn("PCCT header not found.\n"); > + status = AE_NOT_FOUND; > + goto out_err; > + } > + > + status = acpi_table_parse_entries(ACPI_SIG_PCCT, > + sizeof(struct acpi_table_pcct), > + ACPI_PCCT_TYPE_GENERIC_SUBSPACE, > + parse_pcc_subspace, MAX_PCC_SUBSPACES); > + > + if (ACPI_SUCCESS(status)) > + pr_err("Error parsing PCC subspaces from PCCT\n"); > + > + pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl.num_chans); > + > + pcc_mbox_ctrl.chans = pcc_mbox_chan; > + pcc_mbox_ctrl.ops = &pcc_chan_ops; > + pcc_mbox_ctrl.txdone_poll = true; > + pcc_mbox_ctrl.txpoll_period = 1; > + > +out_err: > + return ACPI_SUCCESS(status) ? 1 : 0; Should the return value of 1 here be -EINVAL? Thanks and best regards -Lv > +} > + > +static int pcc_mbox_probe(struct platform_device *pdev) > +{ > + int ret = 0; > + > + 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 -EINVAL; > + } > + > + 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); > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
