linux/drivers/gpu/drm/i915/vlv_sideband.c

// SPDX-License-Identifier: MIT
/*
 * Copyright © 2013-2021 Intel Corporation
 */

#include "i915_drv.h"
#include "i915_iosf_mbi.h"
#include "i915_reg.h"
#include "vlv_sideband.h"

#include "display/intel_dpio_phy.h"

/*
 * IOSF sideband, see VLV2_SidebandMsg_HAS.docx and
 * VLV_VLV2_PUNIT_HAS_0.8.docx
 */

/* Standard MMIO read, non-posted */
#define SB_MRD_NP	0x00
/* Standard MMIO write, non-posted */
#define SB_MWR_NP	0x01
/* Private register read, double-word addressing, non-posted */
#define SB_CRRDDA_NP	0x06
/* Private register write, double-word addressing, non-posted */
#define SB_CRWRDA_NP	0x07

static void ping(void *info)
{
}

static void __vlv_punit_get(struct drm_i915_private *i915)
{
	iosf_mbi_punit_acquire();

	/*
	 * Prevent the cpu from sleeping while we use this sideband, otherwise
	 * the punit may cause a machine hang. The issue appears to be isolated
	 * with changing the power state of the CPU package while changing
	 * the power state via the punit, and we have only observed it
	 * reliably on 4-core Baytail systems suggesting the issue is in the
	 * power delivery mechanism and likely to be board/function
	 * specific. Hence we presume the workaround needs only be applied
	 * to the Valleyview P-unit and not all sideband communications.
	 */
	if (IS_VALLEYVIEW(i915)) {
		cpu_latency_qos_update_request(&i915->sb_qos, 0);
		on_each_cpu(ping, NULL, 1);
	}
}

static void __vlv_punit_put(struct drm_i915_private *i915)
{
	if (IS_VALLEYVIEW(i915))
		cpu_latency_qos_update_request(&i915->sb_qos,
					       PM_QOS_DEFAULT_VALUE);

	iosf_mbi_punit_release();
}

void vlv_iosf_sb_get(struct drm_i915_private *i915, unsigned long ports)
{
	if (ports & BIT(VLV_IOSF_SB_PUNIT))
		__vlv_punit_get(i915);

	mutex_lock(&i915->sb_lock);
}

void vlv_iosf_sb_put(struct drm_i915_private *i915, unsigned long ports)
{
	mutex_unlock(&i915->sb_lock);

	if (ports & BIT(VLV_IOSF_SB_PUNIT))
		__vlv_punit_put(i915);
}

static int vlv_sideband_rw(struct drm_i915_private *i915,
			   u32 devfn, u32 port, u32 opcode,
			   u32 addr, u32 *val)
{
	struct intel_uncore *uncore = &i915->uncore;
	const bool is_read = (opcode == SB_MRD_NP || opcode == SB_CRRDDA_NP);
	int err;

	lockdep_assert_held(&i915->sb_lock);
	if (port == IOSF_PORT_PUNIT)
		iosf_mbi_assert_punit_acquired();

	/* Flush the previous comms, just in case it failed last time. */
	if (intel_wait_for_register(uncore,
				    VLV_IOSF_DOORBELL_REQ, IOSF_SB_BUSY, 0,
				    5)) {
		drm_dbg(&i915->drm, "IOSF sideband idle wait (%s) timed out\n",
			is_read ? "read" : "write");
		return -EAGAIN;
	}

	preempt_disable();

	intel_uncore_write_fw(uncore, VLV_IOSF_ADDR, addr);
	intel_uncore_write_fw(uncore, VLV_IOSF_DATA, is_read ? 0 : *val);
	intel_uncore_write_fw(uncore, VLV_IOSF_DOORBELL_REQ,
			      (devfn << IOSF_DEVFN_SHIFT) |
			      (opcode << IOSF_OPCODE_SHIFT) |
			      (port << IOSF_PORT_SHIFT) |
			      (0xf << IOSF_BYTE_ENABLES_SHIFT) |
			      (0 << IOSF_BAR_SHIFT) |
			      IOSF_SB_BUSY);

	if (__intel_wait_for_register_fw(uncore,
					 VLV_IOSF_DOORBELL_REQ, IOSF_SB_BUSY, 0,
					 10000, 0, NULL) == 0) {
		if (is_read)
			*val = intel_uncore_read_fw(uncore, VLV_IOSF_DATA);
		err = 0;
	} else {
		drm_dbg(&i915->drm, "IOSF sideband finish wait (%s) timed out\n",
			is_read ? "read" : "write");
		err = -ETIMEDOUT;
	}

	preempt_enable();

	return err;
}

u32 vlv_punit_read(struct drm_i915_private *i915, u32 addr)
{
	u32 val = 0;

	vlv_sideband_rw(i915, PCI_DEVFN(0, 0), IOSF_PORT_PUNIT,
			SB_CRRDDA_NP, addr, &val);

	return val;
}

int vlv_punit_write(struct drm_i915_private *i915, u32 addr, u32 val)
{
	return vlv_sideband_rw(i915, PCI_DEVFN(0, 0), IOSF_PORT_PUNIT,
			       SB_CRWRDA_NP, addr, &val);
}

u32 vlv_bunit_read(struct drm_i915_private *i915, u32 reg)
{
	u32 val = 0;

	vlv_sideband_rw(i915, PCI_DEVFN(0, 0), IOSF_PORT_BUNIT,
			SB_CRRDDA_NP, reg, &val);

	return val;
}

void vlv_bunit_write(struct drm_i915_private *i915, u32 reg, u32 val)
{
	vlv_sideband_rw(i915, PCI_DEVFN(0, 0), IOSF_PORT_BUNIT,
			SB_CRWRDA_NP, reg, &val);
}

u32 vlv_nc_read(struct drm_i915_private *i915, u8 addr)
{
	u32 val = 0;

	vlv_sideband_rw(i915, PCI_DEVFN(0, 0), IOSF_PORT_NC,
			SB_CRRDDA_NP, addr, &val);

	return val;
}

u32 vlv_cck_read(struct drm_i915_private *i915, u32 reg)
{
	u32 val = 0;

	vlv_sideband_rw(i915, PCI_DEVFN(0, 0), IOSF_PORT_CCK,
			SB_CRRDDA_NP, reg, &val);

	return val;
}

void vlv_cck_write(struct drm_i915_private *i915, u32 reg, u32 val)
{
	vlv_sideband_rw(i915, PCI_DEVFN(0, 0), IOSF_PORT_CCK,
			SB_CRWRDA_NP, reg, &val);
}

u32 vlv_ccu_read(struct drm_i915_private *i915, u32 reg)
{
	u32 val = 0;

	vlv_sideband_rw(i915, PCI_DEVFN(0, 0), IOSF_PORT_CCU,
			SB_CRRDDA_NP, reg, &val);

	return val;
}

void vlv_ccu_write(struct drm_i915_private *i915, u32 reg, u32 val)
{
	vlv_sideband_rw(i915, PCI_DEVFN(0, 0), IOSF_PORT_CCU,
			SB_CRWRDA_NP, reg, &val);
}

static u32 vlv_dpio_phy_iosf_port(struct drm_i915_private *i915, enum dpio_phy phy)
{
	/*
	 * IOSF_PORT_DPIO: VLV x2 PHY (DP/HDMI B and C), CHV x1 PHY (DP/HDMI D)
	 * IOSF_PORT_DPIO_2: CHV x2 PHY (DP/HDMI B and C)
	 */
	if (IS_CHERRYVIEW(i915))
		return phy == DPIO_PHY0 ? IOSF_PORT_DPIO_2 : IOSF_PORT_DPIO;
	else
		return IOSF_PORT_DPIO;
}

u32 vlv_dpio_read(struct drm_i915_private *i915, enum dpio_phy phy, int reg)
{
	u32 port = vlv_dpio_phy_iosf_port(i915, phy);
	u32 val = 0;

	vlv_sideband_rw(i915, DPIO_DEVFN, port, SB_MRD_NP, reg, &val);

	/*
	 * FIXME: There might be some registers where all 1's is a valid value,
	 * so ideally we should check the register offset instead...
	 */
	drm_WARN(&i915->drm, val == 0xffffffff,
		 "DPIO PHY%d read reg 0x%x == 0x%x\n",
		 phy, reg, val);

	return val;
}

void vlv_dpio_write(struct drm_i915_private *i915,
		    enum dpio_phy phy, int reg, u32 val)
{
	u32 port = vlv_dpio_phy_iosf_port(i915, phy);

	vlv_sideband_rw(i915, DPIO_DEVFN, port, SB_MWR_NP, reg, &val);
}

u32 vlv_flisdsi_read(struct drm_i915_private *i915, u32 reg)
{
	u32 val = 0;

	vlv_sideband_rw(i915, DPIO_DEVFN, IOSF_PORT_FLISDSI, SB_CRRDDA_NP,
			reg, &val);
	return val;
}

void vlv_flisdsi_write(struct drm_i915_private *i915, u32 reg, u32 val)
{
	vlv_sideband_rw(i915, DPIO_DEVFN, IOSF_PORT_FLISDSI, SB_CRWRDA_NP,
			reg, &val);
}