The access_size is part of a union, so doesn't technically exist for
a PIO port (i.e., not MMIO), but we set it anyways.
This doesn't cause a bug today because the other leg of the union
doesn't have anything overlapping with it now, but it's bad, I will
punish myself for writing it that way :-) In the meantime, fix this
and actually name the struct inside the union for clarity of intent
and to avoid such issue in the future.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
We currently rely on some pretty fragile comparison by name to
identify whether a serial port being configured is identical
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The various functions to add a port used to return port->name, and
the callers would immediately iterate all registered ports to "find"
the one just created by comparing that return value with ... port->name.
This is a waste of cycles and code. Instead, have those functions
return "port" directly.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
It is common for PCI based UARTs to use larger than one byte access
sizes. This adds support for this and uses the information present
in SPCR accordingly.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This will allow ports to be added with a pre-set configuration.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
And while at it, unify it as clock frequency in Hz, to match the value in
grub_serial_config struct and do the division by 16 in one common place.
This will simplify adding SPCR support.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This adds the ability for the driver to access UARTs via MMIO instead
of PIO selectively at runtime, and exposes a new function to add an
MMIO port.
In an ideal world, MMIO accessors would be generic and have architecture
specific memory barriers. However, existing drivers don't have them and
most of those "bare metal" drivers tend to be for x86 which doesn't need
them. If necessary, those can be added later.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The GRUB is failing to build with GCC-12 in many places like this:
In function 'init_cbfsdisk',
inlined from 'grub_mod_init' at ../../grub-core/fs/cbfs.c:391:3:
../../grub-core/fs/cbfs.c:345:7: error: array subscript 0 is outside array bounds of 'grub_uint32_t[0]' {aka 'unsigned int[]'} [-Werror=array-bounds]
345 | ptr = *(grub_uint32_t *) 0xfffffffc;
| ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is caused by GCC regression in 11/12 [1]. In a nut shell, the
warning is about detected invalid accesses at non-zero offsets to NULL
pointers. Since hardwired constant address is treated as NULL plus an
offset in the same underlying code, the warning is therefore triggered.
Instead of inserting #pragma all over the places where literal pointers
are accessed to avoid diagnosing array-bounds, we can try to borrow the
idea from Linux kernel that the absolute_pointer() macro [2][3] is used
to disconnect a pointer using literal address from it's original object,
hence GCC won't be able to make assumptions on the boundary while doing
pointer arithmetic. With that we can greatly reduce the code we have to
cover up by making initial literal pointer assignment to use the new
wrapper but not having to track everywhere literal pointers are
accessed. This also makes code looks cleaner.
Please note the grub_absolute_pointer() macro requires to be invoked in
a function as long as it is compound expression. Some global variables
with literal pointers has been changed to local ones in order to use
grub_absolute_pointer() to initialize it. The shuffling is basically done
in a selective and careful way that the variable's scope doesn't matter
being local or global, for example, the global variable must not get
modified at run time throughout. For the record, here's the list of
global variables got shuffled in this patch:
grub-core/commands/i386/pc/drivemap.c:int13slot
grub-core/term/i386/pc/console.c:bios_data_area
grub-core/term/ns8250.c:serial_hw_io_addr
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
[2] https://elixir.bootlin.com/linux/v5.16.14/source/include/linux/compiler.h#L180
[3] https://elixir.bootlin.com/linux/v5.16.14/source/include/linux/compiler-gcc.h#L31
Signed-off-by: Michael Chang <mchang@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
