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Subject[RFC v2 08/39] drm: handle HAS_IOPORT dependencies
Date
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: Niklas Schnelle <schnelle@linux.ibm.com>
---
drivers/gpu/drm/qxl/Kconfig | 1 +
drivers/gpu/drm/tiny/bochs.c | 19 +++++++++++++++++++
drivers/gpu/drm/tiny/cirrus.c | 2 ++
3 files changed, 22 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 ed971c8bb446..9acc726d99ec 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-or-later

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

#include <drm/drm_aperture.h>
@@ -102,7 +103,11 @@ static void bochs_vga_writeb(struct bochs_device *bochs, u16 ioport, u8 val)

writeb(val, bochs->mmio + offset);
} else {
+#ifdef HAS_IOPORT
outb(val, ioport);
+#else
+ WARN_ONCE(1, "Non-MMIO bochs device needs HAS_IOPORT");
+#endif
}
}

@@ -116,7 +121,12 @@ static u8 bochs_vga_readb(struct bochs_device *bochs, u16 ioport)

return readb(bochs->mmio + offset);
} else {
+#ifdef HAS_IOPORT
return inb(ioport);
+#else
+ WARN_ONCE(1, "Non-MMIO bochs device needs HAS_IOPORT");
+ return 0xff;
+#endif
}
}

@@ -129,8 +139,13 @@ static u16 bochs_dispi_read(struct bochs_device *bochs, u16 reg)

ret = readw(bochs->mmio + offset);
} else {
+#ifdef HAS_IOPORT
outw(reg, VBE_DISPI_IOPORT_INDEX);
ret = inw(VBE_DISPI_IOPORT_DATA);
+#else
+ WARN_ONCE(1, "Non-MMIO bochs device needs HAS_IOPORT");
+ ret = 0xffff;
+#endif
}
return ret;
}
@@ -142,8 +157,12 @@ static void bochs_dispi_write(struct bochs_device *bochs, u16 reg, u16 val)

writew(val, bochs->mmio + offset);
} else {
+#ifdef HAS_IOPORT
outw(reg, VBE_DISPI_IOPORT_INDEX);
outw(val, VBE_DISPI_IOPORT_DATA);
+#else
+ WARN_ONCE(1, "Non-MMIO bochs device needs HAS_IOPORT");
+#endif
}
}

diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
index c8e791840862..0dc4788c5399 100644
--- a/drivers/gpu/drm/tiny/cirrus.c
+++ b/drivers/gpu/drm/tiny/cirrus.c
@@ -306,8 +306,10 @@ static int cirrus_mode_set(struct cirrus_device *cirrus,

cirrus_set_start_address(cirrus, 0);

+#ifdef CONFIG_HAS_IOPORT
/* Unblank (needed on S3 resume, vgabios doesn't do it then) */
outb(0x20, 0x3c0);
+#endif

drm_dev_exit(idx);
return 0;
--
2.32.0
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