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x86/earlyprintk: Clean up pciserial

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While working on a GRUB patch to support PCI-serial, a number of
cleanups were suggested that apply to the code I took inspiration from.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>   # pci_ids.h
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lkml.kernel.org/r/YwdeyCEtW+wa+QhH@worktop.programming.kicks-ass.net
This commit is contained in:
Peter Zijlstra 2022-08-25 13:36:40 +02:00
parent b90cb10531
commit bc12b70f7d
2 changed files with 10 additions and 7 deletions
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14
arch/x86/kernel/early_printk.c
View file

@ -264,11 +264,11 @@ static __init void early_pci_serial_init(char *s)
bar0 = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
/*
* Verify it is a UART type device
* Verify it is a 16550-UART type device
*/
if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
(classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
(((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */ {
(((classcode >> 8) & 0xff) != PCI_SERIAL_16550_COMPATIBLE)) {
if (!force)
return;
}
@ -276,22 +276,22 @@ static __init void early_pci_serial_init(char *s)
/*
* Determine if it is IO or memory mapped
*/
if (bar0 & 0x01) {
if ((bar0 & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
/* it is IO mapped */
serial_in = io_serial_in;
serial_out = io_serial_out;
early_serial_base = bar0&0xfffffffc;
early_serial_base = bar0 & PCI_BASE_ADDRESS_IO_MASK;
write_pci_config(bus, slot, func, PCI_COMMAND,
cmdreg|PCI_COMMAND_IO);
cmdreg|PCI_COMMAND_IO);
} else {
/* It is memory mapped - assume 32-bit alignment */
serial_in = mem32_serial_in;
serial_out = mem32_serial_out;
/* WARNING! assuming the address is always in the first 4G */
early_serial_base =
(unsigned long)early_ioremap(bar0 & 0xfffffff0, 0x10);
(unsigned long)early_ioremap(bar0 & PCI_BASE_ADDRESS_MEM_MASK, 0x10);
write_pci_config(bus, slot, func, PCI_COMMAND,
cmdreg|PCI_COMMAND_MEMORY);
cmdreg|PCI_COMMAND_MEMORY);
}
/*

3
include/linux/pci_ids.h
View file

@ -75,6 +75,9 @@
#define PCI_CLASS_COMMUNICATION_MODEM 0x0703
#define PCI_CLASS_COMMUNICATION_OTHER 0x0780
/* Interface for SERIAL/MODEM */
#define PCI_SERIAL_16550_COMPATIBLE 0x02
#define PCI_BASE_CLASS_SYSTEM 0x08
#define PCI_CLASS_SYSTEM_PIC 0x0800
#define PCI_CLASS_SYSTEM_PIC_IOAPIC 0x080010