15  *  PCC (Platform Communication Channel) is defined in the ACPI 5.0+
20  *  shared memory regions as defined in the PCC table entries. The PCC
21  *  specification supports a Doorbell mechanism for the PCC clients
23  *  is also specified in each PCC table entry.
27  *  PCC Reads:
31  *  * Client issues mbox_send_message() which rings the PCC doorbell
32  *		for its PCC channel.
37  *  PCC Writes:
42  *  * Client issues mbox_send_message() which rings the PCC doorbell
43  *		for its PCC channel.
51  *	For more details about PCC, please see the ACPI specification from
54  *  This file implements PCC as a Mailbox controller and allows for PCC
68 #include <acpi/pcc.h>
72 #define MBOX_IRQ_NAME		"pcc-mbox"
85  * get_pcc_channel - Given a PCC subspace idx, get
87  * @id: PCC subspace index.
101  * PCC can be used with perf critical drivers such as CPPC
103  * use it to read/write to PCC registers such as doorbell register
106  * write from perf critical registers such as PCC doorbell register
161  * pcc_map_interrupt - Map a PCC subspace GSI to a linux IRQ number
185  * pcc_mbox_irq - PCC mailbox interrupt handler
227  * pcc_mbox_request_channel - PCC clients call this function to
228  *		request a pointer to their PCC subspace, from which they
232  * @subspace_id: The PCC Subspace index as parsed in the PCC client
233  *		ACPI package. This is used to lookup the array of PCC
234  *		subspaces as parsed by the PCC Mailbox controller.
247 	 * Each PCC Subspace is a Mailbox Channel.  in pcc_mbox_request_channel()
248 	 * The PCC Clients get their PCC Subspace ID  in pcc_mbox_request_channel()
250 	 * This returns a pointer to the PCC subspace  in pcc_mbox_request_channel()
278 			dev_err(dev, "failed to register PCC interrupt %d\n",  in pcc_mbox_request_channel()
323  *		here only to ring the channel doorbell. The PCC client
325  *		order to maintain atomicity over PCC channel once
329  *		only for debug after PCC transaction completes.
376  * parse_pcc_subspaces -- Count PCC subspaces defined
380  * Return: If we find a PCC subspace entry of a valid type, return 0.
383  * This gets called for each entry in the PCC table.
397  * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register
398  *		There should be one entry per PCC client.
399  * @id: PCC subspace index.
404  * This gets called for each entry in the PCC table.
412 		pr_err("PCC GSI %d not registered\n",  in pcc_parse_subspace_irq()
425 			pr_err("Failed to ioremap PCC ACK register\n");  in pcc_parse_subspace_irq()
466 			pr_warn("Error parsing PCC subspaces from PCCT\n");  in acpi_pcc_probe()
468 			pr_warn("Invalid PCCT: %d PCC subspaces\n", count);  in acpi_pcc_probe()
475 		pr_err("Could not allocate space for PCC mbox channels\n");  in acpi_pcc_probe()
497 	/* Point to the first PCC subspace entry */  in acpi_pcc_probe()
535 	pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl.num_chans);  in acpi_pcc_probe()
569 	pr_info("Registering PCC driver as Mailbox controller\n");  in pcc_mbox_probe()
573 		pr_err("Err registering PCC as Mailbox controller: %d\n", ret);  in pcc_mbox_probe()
596 	/* Check if PCC support is available. */  in pcc_init()
600 		pr_debug("ACPI PCC probe failed.\n");  in pcc_init()
608 		pr_debug("Err creating PCC platform bundle\n");  in pcc_init()
616  * Make PCC init postcore so that users of this mailbox