1// SPDX-License-Identifier: MIT
  2/*
  3 * Copyright © 2019 Intel Corporation
  4 */
  5
  6#include <linux/delay.h>
  7#include <linux/vgaarb.h>
  8
  9#include <video/vga.h>
 10#include "soc/intel_gmch.h"
 11
 12#include "i915_drv.h"
 13#include "i915_reg.h"
 14#include "intel_de.h"
 15#include "intel_vga.h"
 16
 17static i915_reg_t intel_vga_cntrl_reg(struct intel_display *display)
 18{
 19	if (display->platform.valleyview || display->platform.cherryview)
 20		return VLV_VGACNTRL;
 21	else if (DISPLAY_VER(display) >= 5)
 22		return CPU_VGACNTRL;
 23	else
 24		return VGACNTRL;
 25}
 26
 27/* Disable the VGA plane that we never use */
 28void intel_vga_disable(struct intel_display *display)
 29{
 30	struct pci_dev *pdev = to_pci_dev(display->drm->dev);
 31	i915_reg_t vga_reg = intel_vga_cntrl_reg(display);
 32	u8 sr1;
 33
 34	if (intel_de_read(display, vga_reg) & VGA_DISP_DISABLE)
 35		return;
 36
 37	/* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */
 38	vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
 39	outb(0x01, VGA_SEQ_I);
 40	sr1 = inb(VGA_SEQ_D);
 41	outb(sr1 | VGA_SR01_SCREEN_OFF, VGA_SEQ_D);
 42	vga_put(pdev, VGA_RSRC_LEGACY_IO);
 43	udelay(300);
 44
 45	intel_de_write(display, vga_reg, VGA_DISP_DISABLE);
 46	intel_de_posting_read(display, vga_reg);
 47}
 48
 49void intel_vga_redisable_power_on(struct intel_display *display)
 50{
 51	i915_reg_t vga_reg = intel_vga_cntrl_reg(display);
 52
 53	if (!(intel_de_read(display, vga_reg) & VGA_DISP_DISABLE)) {
 54		drm_dbg_kms(display->drm,
 55			    "Something enabled VGA plane, disabling it\n");
 56		intel_vga_disable(display);
 57	}
 58}
 59
 60void intel_vga_redisable(struct intel_display *display)
 61{
 62	struct drm_i915_private *i915 = to_i915(display->drm);
 63	intel_wakeref_t wakeref;
 64
 65	/*
 66	 * This function can be called both from intel_modeset_setup_hw_state or
 67	 * at a very early point in our resume sequence, where the power well
 68	 * structures are not yet restored. Since this function is at a very
 69	 * paranoid "someone might have enabled VGA while we were not looking"
 70	 * level, just check if the power well is enabled instead of trying to
 71	 * follow the "don't touch the power well if we don't need it" policy
 72	 * the rest of the driver uses.
 73	 */
 74	wakeref = intel_display_power_get_if_enabled(i915, POWER_DOMAIN_VGA);
 75	if (!wakeref)
 76		return;
 77
 78	intel_vga_redisable_power_on(display);
 79
 80	intel_display_power_put(i915, POWER_DOMAIN_VGA, wakeref);
 81}
 82
 83void intel_vga_reset_io_mem(struct intel_display *display)
 84{
 85	struct pci_dev *pdev = to_pci_dev(display->drm->dev);
 86
 87	/*
 88	 * After we re-enable the power well, if we touch VGA register 0x3d5
 89	 * we'll get unclaimed register interrupts. This stops after we write
 90	 * anything to the VGA MSR register. The vgacon module uses this
 91	 * register all the time, so if we unbind our driver and, as a
 92	 * consequence, bind vgacon, we'll get stuck in an infinite loop at
 93	 * console_unlock(). So make here we touch the VGA MSR register, making
 94	 * sure vgacon can keep working normally without triggering interrupts
 95	 * and error messages.
 96	 */
 97	vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
 98	outb(inb(VGA_MIS_R), VGA_MIS_W);
 99	vga_put(pdev, VGA_RSRC_LEGACY_IO);
100}
101
102int intel_vga_register(struct intel_display *display)
103{
104
105	struct pci_dev *pdev = to_pci_dev(display->drm->dev);
106	int ret;
107
108	/*
109	 * If we have > 1 VGA cards, then we need to arbitrate access to the
110	 * common VGA resources.
111	 *
112	 * If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA),
113	 * then we do not take part in VGA arbitration and the
114	 * vga_client_register() fails with -ENODEV.
115	 */
116	ret = vga_client_register(pdev, intel_gmch_vga_set_decode);
117	if (ret && ret != -ENODEV)
118		return ret;
119
120	return 0;
121}
122
123void intel_vga_unregister(struct intel_display *display)
124{
125	struct pci_dev *pdev = to_pci_dev(display->drm->dev);
126
127	vga_client_unregister(pdev);
128}