[RFC v2 08/39] drm: handle HAS_IOPORT dependencies

[Niklas Schnelle]

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 <a...@kernel.org>
Signed-off-by: Niklas Schnelle <schne...@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