154 lines
4.1 KiB
C
154 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Author: Sudeep Holla <sudeep.holla@arm.com>
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* Copyright 2021 Arm Limited
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*
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* The PCC Address Space also referred as PCC Operation Region pertains to the
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* region of PCC subspace that succeeds the PCC signature. The PCC Operation
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* Region works in conjunction with the PCC Table(Platform Communications
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* Channel Table). PCC subspaces that are marked for use as PCC Operation
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* Regions must not be used as PCC subspaces for the standard ACPI features
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* such as CPPC, RASF, PDTT and MPST. These standard features must always use
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* the PCC Table instead.
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*
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* This driver sets up the PCC Address Space and installs an handler to enable
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* handling of PCC OpRegion in the firmware.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/acpi.h>
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#include <linux/completion.h>
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#include <linux/idr.h>
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#include <linux/io.h>
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#include <acpi/pcc.h>
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/*
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* Arbitrary retries in case the remote processor is slow to respond
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* to PCC commands
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*/
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#define PCC_CMD_WAIT_RETRIES_NUM 500ULL
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struct pcc_data {
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struct pcc_mbox_chan *pcc_chan;
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void __iomem *pcc_comm_addr;
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struct completion done;
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struct mbox_client cl;
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struct acpi_pcc_info ctx;
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};
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static struct acpi_pcc_info pcc_ctx;
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static void pcc_rx_callback(struct mbox_client *cl, void *m)
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{
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struct pcc_data *data = container_of(cl, struct pcc_data, cl);
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complete(&data->done);
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}
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static acpi_status
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acpi_pcc_address_space_setup(acpi_handle region_handle, u32 function,
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void *handler_context, void **region_context)
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{
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struct pcc_data *data;
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struct acpi_pcc_info *ctx = handler_context;
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struct pcc_mbox_chan *pcc_chan;
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static acpi_status ret;
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data = kzalloc(sizeof(*data), GFP_KERNEL);
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if (!data)
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return AE_NO_MEMORY;
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data->cl.rx_callback = pcc_rx_callback;
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data->cl.knows_txdone = true;
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data->ctx.length = ctx->length;
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data->ctx.subspace_id = ctx->subspace_id;
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data->ctx.internal_buffer = ctx->internal_buffer;
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init_completion(&data->done);
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data->pcc_chan = pcc_mbox_request_channel(&data->cl, ctx->subspace_id);
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if (IS_ERR(data->pcc_chan)) {
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pr_err("Failed to find PCC channel for subspace %d\n",
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ctx->subspace_id);
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ret = AE_NOT_FOUND;
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goto err_free_data;
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}
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pcc_chan = data->pcc_chan;
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if (!pcc_chan->mchan->mbox->txdone_irq) {
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pr_err("This channel-%d does not support interrupt.\n",
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ctx->subspace_id);
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ret = AE_SUPPORT;
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goto err_free_channel;
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}
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data->pcc_comm_addr = acpi_os_ioremap(pcc_chan->shmem_base_addr,
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pcc_chan->shmem_size);
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if (!data->pcc_comm_addr) {
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pr_err("Failed to ioremap PCC comm region mem for %d\n",
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ctx->subspace_id);
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ret = AE_NO_MEMORY;
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goto err_free_channel;
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}
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*region_context = data;
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return AE_OK;
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err_free_channel:
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pcc_mbox_free_channel(data->pcc_chan);
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err_free_data:
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kfree(data);
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return ret;
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}
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static acpi_status
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acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr,
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u32 bits, acpi_integer *value,
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void *handler_context, void *region_context)
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{
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int ret;
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struct pcc_data *data = region_context;
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u64 usecs_lat;
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reinit_completion(&data->done);
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/* Write to Shared Memory */
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memcpy_toio(data->pcc_comm_addr, (void *)value, data->ctx.length);
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ret = mbox_send_message(data->pcc_chan->mchan, NULL);
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if (ret < 0)
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return AE_ERROR;
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/*
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* pcc_chan->latency is just a Nominal value. In reality the remote
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* processor could be much slower to reply. So add an arbitrary
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* amount of wait on top of Nominal.
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*/
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usecs_lat = PCC_CMD_WAIT_RETRIES_NUM * data->pcc_chan->latency;
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ret = wait_for_completion_timeout(&data->done,
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usecs_to_jiffies(usecs_lat));
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if (ret == 0) {
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pr_err("PCC command executed timeout!\n");
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return AE_TIME;
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}
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mbox_chan_txdone(data->pcc_chan->mchan, ret);
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memcpy_fromio(value, data->pcc_comm_addr, data->ctx.length);
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return AE_OK;
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}
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void __init acpi_init_pcc(void)
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{
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acpi_status status;
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status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
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ACPI_ADR_SPACE_PLATFORM_COMM,
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&acpi_pcc_address_space_handler,
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&acpi_pcc_address_space_setup,
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&pcc_ctx);
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if (ACPI_FAILURE(status))
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pr_alert("OperationRegion handler could not be installed\n");
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}
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