[PATCH v5 09/44] drm: handle HAS_IOPORT dependencies

Niklas Schnelle
2023-05-22T10:52:21Z

In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
not being declared. We thus need to add HAS_IOPORT as dependency for
those drivers using them. In the bochs driver there is optional MMIO
support detected at runtime, warn if this isn't taken when
HAS_IOPORT is not defined.

There is also a direct and hard coded use in cirrus.c which according to
the comment is only necessary during resume. Let's just skip this as
for example s390 which doesn't have I/O port support also doesen't
support suspend/resume.

Co-developed-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
drivers/gpu/drm/qxl/Kconfig | 1 +
drivers/gpu/drm/tiny/bochs.c | 17 +++++++++++++++++
drivers/gpu/drm/tiny/cirrus.c | 2 ++
3 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/qxl/Kconfig b/drivers/gpu/drm/qxl/Kconfig
index ca3f51c2a8fe..d0e0d440c8d9 100644
--- a/drivers/gpu/drm/qxl/Kconfig
+++ b/drivers/gpu/drm/qxl/Kconfig
@@ -2,6 +2,7 @@
config DRM_QXL
tristate "QXL virtual GPU"
depends on DRM && PCI && MMU
+ depends on HAS_IOPORT
select DRM_KMS_HELPER
select DRM_TTM
select DRM_TTM_HELPER
diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
index d254679a136e..3710339407cc 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c
@@ -2,6 +2,7 @@

#include <linux/module.h>
#include <linux/pci.h>
+#include <asm/bug.h>

#include <drm/drm_aperture.h>
#include <drm/drm_atomic_helper.h>
@@ -105,7 +106,9 @@ static void bochs_vga_writeb(struct bochs_device *bochs, u16 ioport, u8 val)

writeb(val, bochs->mmio + offset);
} else {
+#ifdef CONFIG_HAS_IOPORT
outb(val, ioport);
+#endif
}
}

@@ -119,7 +122,11 @@ static u8 bochs_vga_readb(struct bochs_device *bochs, u16 ioport)

return readb(bochs->mmio + offset);
} else {
+#ifdef CONFIG_HAS_IOPORT
return inb(ioport);
+#else
+ return 0xff;
+#endif
}
}

@@ -132,8 +139,12 @@ static u16 bochs_dispi_read(struct bochs_device *bochs, u16 reg)

ret = readw(bochs->mmio + offset);
} else {
+#ifdef CONFIG_HAS_IOPORT
outw(reg, VBE_DISPI_IOPORT_INDEX);
ret = inw(VBE_DISPI_IOPORT_DATA);
+#else
+ ret = 0xffff;
+#endif
}
return ret;
}
@@ -145,8 +156,10 @@ static void bochs_dispi_write(struct bochs_device *bochs, u16 reg, u16 val)

writew(val, bochs->mmio + offset);
} else {
+#ifdef CONFIG_HAS_IOPORT
outw(reg, VBE_DISPI_IOPORT_INDEX);
outw(val, VBE_DISPI_IOPORT_DATA);
+#endif
}
}

@@ -229,6 +242,10 @@ static int bochs_hw_init(struct drm_device *dev)
return -ENOMEM;
}
} else {
+ if (!IS_ENABLED(CONFIG_HAS_IOPORT)) {
+ DRM_ERROR("I/O ports are not supported\n");
+ return -EIO;
+ }
ioaddr = VBE_DISPI_IOPORT_INDEX;
iosize = 2;
if (!request_region(ioaddr, iosize, "bochs-drm")) {
diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
index 594bc472862f..c65fea049bc7 100644
--- a/drivers/gpu/drm/tiny/cirrus.c
+++ b/drivers/gpu/drm/tiny/cirrus.c
@@ -508,8 +508,10 @@ static void cirrus_crtc_helper_atomic_enable(struct drm_crtc *crtc,

cirrus_mode_set(cirrus, &crtc_state->mode);

+#ifdef CONFIG_HAS_IOPORT
/* Unblank (needed on S3 resume, vgabios doesn't do it then) */
outb(VGA_AR_ENABLE_DISPLAY, VGA_ATT_W);
+#endif

drm_dev_exit(idx);
}
--
2.39.2