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// SPDX-License-Identifier: MIT
/*
* Copyright © 2019 Intel Corporation
*/
#include <linux/pci.h>
#include <linux/vgaarb.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "intel_de.h"
#include "intel_vga.h"
static i915_reg_t intel_vga_cntrl_reg(struct drm_i915_private *i915)
{
if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915))
return VLV_VGACNTRL;
else if (DISPLAY_VER(i915) >= 5)
return CPU_VGACNTRL;
else
return VGACNTRL;
}
/* Disable the VGA plane that we never use */
void intel_vga_disable(struct drm_i915_private *dev_priv)
{
struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
u8 sr1;
if (intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)
return;
/* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */
vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
outb(SR01, VGA_SR_INDEX);
sr1 = inb(VGA_SR_DATA);
outb(sr1 | 1 << 5, VGA_SR_DATA);
vga_put(pdev, VGA_RSRC_LEGACY_IO);
udelay(300);
intel_de_write(dev_priv, vga_reg, VGA_DISP_DISABLE);
intel_de_posting_read(dev_priv, vga_reg);
}
void intel_vga_redisable_power_on(struct drm_i915_private *dev_priv)
{
i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
if (!(intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)) {
drm_dbg_kms(&dev_priv->drm,
"Something enabled VGA plane, disabling it\n");
intel_vga_disable(dev_priv);
}
}
void intel_vga_redisable(struct drm_i915_private *i915)
{
intel_wakeref_t wakeref;
/*
* This function can be called both from intel_modeset_setup_hw_state or
* at a very early point in our resume sequence, where the power well
* structures are not yet restored. Since this function is at a very
* paranoid "someone might have enabled VGA while we were not looking"
* level, just check if the power well is enabled instead of trying to
* follow the "don't touch the power well if we don't need it" policy
* the rest of the driver uses.
*/
wakeref = intel_display_power_get_if_enabled(i915, POWER_DOMAIN_VGA);
if (!wakeref)
return;
intel_vga_redisable_power_on(i915);
intel_display_power_put(i915, POWER_DOMAIN_VGA, wakeref);
}
void intel_vga_reset_io_mem(struct drm_i915_private *i915)
{
struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
/*
* After we re-enable the power well, if we touch VGA register 0x3d5
* we'll get unclaimed register interrupts. This stops after we write
* anything to the VGA MSR register. The vgacon module uses this
* register all the time, so if we unbind our driver and, as a
* consequence, bind vgacon, we'll get stuck in an infinite loop at
* console_unlock(). So make here we touch the VGA MSR register, making
* sure vgacon can keep working normally without triggering interrupts
* and error messages.
*/
vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
outb(inb(VGA_MSR_READ), VGA_MSR_WRITE);
vga_put(pdev, VGA_RSRC_LEGACY_IO);
}
static int
intel_vga_set_state(struct drm_i915_private *i915, bool enable_decode)
{
unsigned int reg = DISPLAY_VER(i915) >= 6 ? SNB_GMCH_CTRL : INTEL_GMCH_CTRL;
u16 gmch_ctrl;
if (pci_read_config_word(i915->bridge_dev, reg, &gmch_ctrl)) {
drm_err(&i915->drm, "failed to read control word\n");
return -EIO;
}
if (!!(gmch_ctrl & INTEL_GMCH_VGA_DISABLE) == !enable_decode)
return 0;
if (enable_decode)
gmch_ctrl &= ~INTEL_GMCH_VGA_DISABLE;
else
gmch_ctrl |= INTEL_GMCH_VGA_DISABLE;
if (pci_write_config_word(i915->bridge_dev, reg, gmch_ctrl)) {
drm_err(&i915->drm, "failed to write control word\n");
return -EIO;
}
return 0;
}
static unsigned int
intel_vga_set_decode(struct pci_dev *pdev, bool enable_decode)
{
struct drm_i915_private *i915 = pdev_to_i915(pdev);
intel_vga_set_state(i915, enable_decode);
if (enable_decode)
return VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
else
return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
}
int intel_vga_register(struct drm_i915_private *i915)
{
struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
int ret;
/*
* If we have > 1 VGA cards, then we need to arbitrate access to the
* common VGA resources.
*
* If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA),
* then we do not take part in VGA arbitration and the
* vga_client_register() fails with -ENODEV.
*/
ret = vga_client_register(pdev, intel_vga_set_decode);
if (ret && ret != -ENODEV)
return ret;
return 0;
}
void intel_vga_unregister(struct drm_i915_private *i915)
{
struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
vga_client_unregister(pdev);
}
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