1 files changed, 120 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_pcc.c b/drivers/acpi/acpi_pcc.c
new file mode 100644
index 000000000000..41e3ebd204ff
--- /dev/null
+++ b/drivers/acpi/acpi_pcc.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Author: Sudeep Holla <sudeep.holla@arm.com>
+ * Copyright 2021 Arm Limited
+ *
+ * The PCC Address Space also referred as PCC Operation Region pertains to the
+ * region of PCC subspace that succeeds the PCC signature. The PCC Operation
+ * Region works in conjunction with the PCC Table(Platform Communications
+ * Channel Table). PCC subspaces that are marked for use as PCC Operation
+ * Regions must not be used as PCC subspaces for the standard ACPI features
+ * such as CPPC, RASF, PDTT and MPST. These standard features must always use
+ * the PCC Table instead.
+ *
+ * This driver sets up the PCC Address Space and installs an handler to enable
+ * handling of PCC OpRegion in the firmware.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/acpi.h>
+#include <linux/completion.h>
+#include <linux/idr.h>
+#include <linux/io.h>
+
+#include <acpi/pcc.h>
+
+struct pcc_data {
+	struct pcc_mbox_chan *pcc_chan;
+	void __iomem *pcc_comm_addr;
+	struct completion done;
+	struct mbox_client cl;
+	struct acpi_pcc_info ctx;
+};
+
+struct acpi_pcc_info pcc_ctx;
+
+static void pcc_rx_callback(struct mbox_client *cl, void *m)
+{
+	struct pcc_data *data = container_of(cl, struct pcc_data, cl);
+
+	complete(&data->done);
+}
+
+static acpi_status
+acpi_pcc_address_space_setup(acpi_handle region_handle, u32 function,
+			     void *handler_context,  void **region_context)
+{
+	struct pcc_data *data;
+	struct acpi_pcc_info *ctx = handler_context;
+	struct pcc_mbox_chan *pcc_chan;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return AE_NO_MEMORY;
+
+	data->cl.rx_callback = pcc_rx_callback;
+	data->cl.knows_txdone = true;
+	data->ctx.length = ctx->length;
+	data->ctx.subspace_id = ctx->subspace_id;
+	data->ctx.internal_buffer = ctx->internal_buffer;
+
+	init_completion(&data->done);
+	data->pcc_chan = pcc_mbox_request_channel(&data->cl, ctx->subspace_id);
+	if (IS_ERR(data->pcc_chan)) {
+		pr_err("Failed to find PCC channel for subspace %d\n",
+		       ctx->subspace_id);
+		return AE_NOT_FOUND;
+	}
+
+	pcc_chan = data->pcc_chan;
+	data->pcc_comm_addr = acpi_os_ioremap(pcc_chan->shmem_base_addr,
+					      pcc_chan->shmem_size);
+	if (!data->pcc_comm_addr) {
+		pr_err("Failed to ioremap PCC comm region mem for %d\n",
+		       ctx->subspace_id);
+		return AE_NO_MEMORY;
+	}
+
+	*region_context = data;
+	return AE_OK;
+}
+
+static acpi_status
+acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr,
+			       u32 bits, acpi_integer *value,
+			       void *handler_context, void *region_context)
+{
+	int ret;
+	struct pcc_data *data = region_context;
+
+	reinit_completion(&data->done);
+
+	/* Write to Shared Memory */
+	memcpy_toio(data->pcc_comm_addr, (void *)value, data->ctx.length);
+
+	ret = mbox_send_message(data->pcc_chan->mchan, NULL);
+	if (ret < 0)
+		return AE_ERROR;
+
+	if (data->pcc_chan->mchan->mbox->txdone_irq)
+		wait_for_completion(&data->done);
+
+	mbox_client_txdone(data->pcc_chan->mchan, ret);
+
+	memcpy_fromio(value, data->pcc_comm_addr, data->ctx.length);
+
+	return AE_OK;
+}
+
+void __init acpi_init_pcc(void)
+{
+	acpi_status status;
+
+	status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
+						    ACPI_ADR_SPACE_PLATFORM_COMM,
+						    &acpi_pcc_address_space_handler,
+						    &acpi_pcc_address_space_setup,
+						    &pcc_ctx);
+	if (ACPI_FAILURE(status))
+		pr_alert("OperationRegion handler could not be installed\n");
+}