text: // SPDX-License-Identifier: MIT
  /*
   * Copyright © 2013-2021 Intel Corporation
   */
  
  #include <asm/iosf_mbi.h>
  
  #include "i915_drv.h"
  #include "vlv_sideband.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_iosf_sb_read(struct drm_i915_private *i915, u8 port, u32 reg)
  {
  	u32 val = 0;
  
  	vlv_sideband_rw(i915, PCI_DEVFN(0, 0), port,
  			SB_CRRDDA_NP, reg, &val);
  
  	return val;
  }
  
  void vlv_iosf_sb_write(struct drm_i915_private *i915,
  		       u8 port, u32 reg, u32 val)
  {
  	vlv_sideband_rw(i915, PCI_DEVFN(0, 0), port,
  			SB_CRWRDA_NP, reg, &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 pipe pipe, int reg)
  {
  	u32 port = vlv_dpio_phy_iosf_port(i915, DPIO_PHY(pipe));
  	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 read pipe %c reg 0x%x == 0x%x\n",
  		 pipe_name(pipe), reg, val);
  
  	return val;
  }
  
  void vlv_dpio_write(struct drm_i915_private *i915,
  		    enum pipe pipe, int reg, u32 val)
  {
  	u32 port = vlv_dpio_phy_iosf_port(i915, DPIO_PHY(pipe));
  
  	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);
  }
  