linux/drivers/gpu/drm/xe/xe_pcode.c

// SPDX-License-Identifier: MIT
/*
 * Copyright © 2022 Intel Corporation
 */

#include "xe_pcode.h"

#include <linux/delay.h>
#include <linux/errno.h>

#include <drm/drm_managed.h>

#include "xe_assert.h"
#include "xe_device.h"
#include "xe_mmio.h"
#include "xe_pcode_api.h"

/**
 * DOC: PCODE
 *
 * Xe PCODE is the component responsible for interfacing with the PCODE
 * firmware.
 * It shall provide a very simple ABI to other Xe components, but be the
 * single and consolidated place that will communicate with PCODE. All read
 * and write operations to PCODE will be internal and private to this component.
 *
 * What's next:
 * - PCODE hw metrics
 * - PCODE for display operations
 */

static int pcode_mailbox_status(struct xe_tile *tile)
{ … }

static int __pcode_mailbox_rw(struct xe_tile *tile, u32 mbox, u32 *data0, u32 *data1,
			      unsigned int timeout_ms, bool return_data,
			      bool atomic)
{ … }

static int pcode_mailbox_rw(struct xe_tile *tile, u32 mbox, u32 *data0, u32 *data1,
			    unsigned int timeout_ms, bool return_data,
			    bool atomic)
{ … }

int xe_pcode_write_timeout(struct xe_tile *tile, u32 mbox, u32 data, int timeout)
{ … }

int xe_pcode_read(struct xe_tile *tile, u32 mbox, u32 *val, u32 *val1)
{ … }

static int pcode_try_request(struct xe_tile *tile, u32 mbox,
			     u32 request, u32 reply_mask, u32 reply,
			     u32 *status, bool atomic, int timeout_us, bool locked)
{ … }

/**
 * xe_pcode_request - send PCODE request until acknowledgment
 * @tile: tile
 * @mbox: PCODE mailbox ID the request is targeted for
 * @request: request ID
 * @reply_mask: mask used to check for request acknowledgment
 * @reply: value used to check for request acknowledgment
 * @timeout_base_ms: timeout for polling with preemption enabled
 *
 * Keep resending the @request to @mbox until PCODE acknowledges it, PCODE
 * reports an error or an overall timeout of @timeout_base_ms+50 ms expires.
 * The request is acknowledged once the PCODE reply dword equals @reply after
 * applying @reply_mask. Polling is first attempted with preemption enabled
 * for @timeout_base_ms and if this times out for another 50 ms with
 * preemption disabled.
 *
 * Returns 0 on success, %-ETIMEDOUT in case of a timeout, <0 in case of some
 * other error as reported by PCODE.
 */
int xe_pcode_request(struct xe_tile *tile, u32 mbox, u32 request,
		     u32 reply_mask, u32 reply, int timeout_base_ms)
{ … }
/**
 * xe_pcode_init_min_freq_table - Initialize PCODE's QOS frequency table
 * @tile: tile instance
 * @min_gt_freq: Minimal (RPn) GT frequency in units of 50MHz.
 * @max_gt_freq: Maximal (RP0) GT frequency in units of 50MHz.
 *
 * This function initialize PCODE's QOS frequency table for a proper minimal
 * frequency/power steering decision, depending on the current requested GT
 * frequency. For older platforms this was a more complete table including
 * the IA freq. However for the latest platforms this table become a simple
 * 1-1 Ring vs GT frequency. Even though, without setting it, PCODE might
 * not take the right decisions for some memory frequencies and affect latency.
 *
 * It returns 0 on success, and -ERROR number on failure, -EINVAL if max
 * frequency is higher then the minimal, and other errors directly translated
 * from the PCODE Error returs:
 * - -ENXIO: "Illegal Command"
 * - -ETIMEDOUT: "Timed out"
 * - -EINVAL: "Illegal Data"
 * - -ENXIO, "Illegal Subcommand"
 * - -EBUSY: "PCODE Locked"
 * - -EOVERFLOW, "GT ratio out of range"
 * - -EACCES, "PCODE Rejected"
 * - -EPROTO, "Unknown"
 */
int xe_pcode_init_min_freq_table(struct xe_tile *tile, u32 min_gt_freq,
				 u32 max_gt_freq)
{ … }

/**
 * xe_pcode_ready - Ensure PCODE is initialized
 * @xe: xe instance
 * @locked: true if lock held, false otherwise
 *
 * PCODE init mailbox is polled only on root gt of root tile
 * as the root tile provides the initialization is complete only
 * after all the tiles have completed the initialization.
 * Called only on early probe without locks and with locks in
 * resume path.
 *
 * Returns 0 on success, and -error number on failure.
 */
int xe_pcode_ready(struct xe_device *xe, bool locked)
{ … }

/**
 * xe_pcode_init: initialize components of PCODE
 * @tile: tile instance
 *
 * This function initializes the xe_pcode component.
 * To be called once only during probe.
 */
void xe_pcode_init(struct xe_tile *tile)
{ … }

/**
 * xe_pcode_probe_early: initializes PCODE
 * @xe: xe instance
 *
 * This function checks the initialization status of PCODE
 * To be called once only during early probe without locks.
 *
 * Returns 0 on success, error code otherwise
 */
int xe_pcode_probe_early(struct xe_device *xe)
{ … }