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| 1 | +// SPDX-License-Identifier: GPL-2.0-only |
| 2 | +/* |
| 3 | + * Author: Sudeep Holla <[email protected]> |
| 4 | + * Copyright 2021 Arm Limited |
| 5 | + * |
| 6 | + * The PCC Address Space also referred as PCC Operation Region pertains to the |
| 7 | + * region of PCC subspace that succeeds the PCC signature. The PCC Operation |
| 8 | + * Region works in conjunction with the PCC Table(Platform Communications |
| 9 | + * Channel Table). PCC subspaces that are marked for use as PCC Operation |
| 10 | + * Regions must not be used as PCC subspaces for the standard ACPI features |
| 11 | + * such as CPPC, RASF, PDTT and MPST. These standard features must always use |
| 12 | + * the PCC Table instead. |
| 13 | + * |
| 14 | + * This driver sets up the PCC Address Space and installs an handler to enable |
| 15 | + * handling of PCC OpRegion in the firmware. |
| 16 | + * |
| 17 | + */ |
| 18 | +#include <linux/kernel.h> |
| 19 | +#include <linux/acpi.h> |
| 20 | +#include <linux/completion.h> |
| 21 | +#include <linux/idr.h> |
| 22 | +#include <linux/io.h> |
| 23 | + |
| 24 | +#include <acpi/pcc.h> |
| 25 | + |
| 26 | +struct pcc_data { |
| 27 | + struct pcc_mbox_chan *pcc_chan; |
| 28 | + void __iomem *pcc_comm_addr; |
| 29 | + struct completion done; |
| 30 | + struct mbox_client cl; |
| 31 | + struct acpi_pcc_info ctx; |
| 32 | +}; |
| 33 | + |
| 34 | +struct acpi_pcc_info pcc_ctx; |
| 35 | + |
| 36 | +static void pcc_rx_callback(struct mbox_client *cl, void *m) |
| 37 | +{ |
| 38 | + struct pcc_data *data = container_of(cl, struct pcc_data, cl); |
| 39 | + |
| 40 | + complete(&data->done); |
| 41 | +} |
| 42 | + |
| 43 | +static acpi_status |
| 44 | +acpi_pcc_address_space_setup(acpi_handle region_handle, u32 function, |
| 45 | + void *handler_context, void **region_context) |
| 46 | +{ |
| 47 | + struct pcc_data *data; |
| 48 | + struct acpi_pcc_info *ctx = handler_context; |
| 49 | + struct pcc_mbox_chan *pcc_chan; |
| 50 | + |
| 51 | + data = kzalloc(sizeof(*data), GFP_KERNEL); |
| 52 | + if (!data) |
| 53 | + return AE_NO_MEMORY; |
| 54 | + |
| 55 | + data->cl.rx_callback = pcc_rx_callback; |
| 56 | + data->cl.knows_txdone = true; |
| 57 | + data->ctx.length = ctx->length; |
| 58 | + data->ctx.subspace_id = ctx->subspace_id; |
| 59 | + data->ctx.internal_buffer = ctx->internal_buffer; |
| 60 | + |
| 61 | + init_completion(&data->done); |
| 62 | + data->pcc_chan = pcc_mbox_request_channel(&data->cl, ctx->subspace_id); |
| 63 | + if (IS_ERR(data->pcc_chan)) { |
| 64 | + pr_err("Failed to find PCC channel for subspace %d\n", |
| 65 | + ctx->subspace_id); |
| 66 | + return AE_NOT_FOUND; |
| 67 | + } |
| 68 | + |
| 69 | + pcc_chan = data->pcc_chan; |
| 70 | + data->pcc_comm_addr = acpi_os_ioremap(pcc_chan->shmem_base_addr, |
| 71 | + pcc_chan->shmem_size); |
| 72 | + if (!data->pcc_comm_addr) { |
| 73 | + pr_err("Failed to ioremap PCC comm region mem for %d\n", |
| 74 | + ctx->subspace_id); |
| 75 | + return AE_NO_MEMORY; |
| 76 | + } |
| 77 | + |
| 78 | + *region_context = data; |
| 79 | + return AE_OK; |
| 80 | +} |
| 81 | + |
| 82 | +static acpi_status |
| 83 | +acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr, |
| 84 | + u32 bits, acpi_integer *value, |
| 85 | + void *handler_context, void *region_context) |
| 86 | +{ |
| 87 | + int ret; |
| 88 | + struct pcc_data *data = region_context; |
| 89 | + |
| 90 | + reinit_completion(&data->done); |
| 91 | + |
| 92 | + /* Write to Shared Memory */ |
| 93 | + memcpy_toio(data->pcc_comm_addr, (void *)value, data->ctx.length); |
| 94 | + |
| 95 | + ret = mbox_send_message(data->pcc_chan->mchan, NULL); |
| 96 | + if (ret < 0) |
| 97 | + return AE_ERROR; |
| 98 | + |
| 99 | + if (data->pcc_chan->mchan->mbox->txdone_irq) |
| 100 | + wait_for_completion(&data->done); |
| 101 | + |
| 102 | + mbox_client_txdone(data->pcc_chan->mchan, ret); |
| 103 | + |
| 104 | + memcpy_fromio(value, data->pcc_comm_addr, data->ctx.length); |
| 105 | + |
| 106 | + return AE_OK; |
| 107 | +} |
| 108 | + |
| 109 | +void __init acpi_init_pcc(void) |
| 110 | +{ |
| 111 | + acpi_status status; |
| 112 | + |
| 113 | + status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT, |
| 114 | + ACPI_ADR_SPACE_PLATFORM_COMM, |
| 115 | + &acpi_pcc_address_space_handler, |
| 116 | + &acpi_pcc_address_space_setup, |
| 117 | + &pcc_ctx); |
| 118 | + if (ACPI_FAILURE(status)) |
| 119 | + pr_alert("OperationRegion handler could not be installed\n"); |
| 120 | +} |
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