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serial: 8250: Move CE4100 quirks to a module under 8250 driver

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There is inconvenient for maintainers and maintainership to have
some quirks under architectural code. Move it to the specific quirk
file like other 8250-compatible drivers do.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250627182743.1273326-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andy Shevchenko 2025-06-27 21:25:00 +03:00 • committed by Greg Kroah-Hartman
parent 5e40169f7a
commit acc902de05
4 changed files with 105 additions and 98 deletions
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6
arch/x86/include/asm/ce4100.h
View file

@ -4,4 +4,10 @@
int ce4100_pci_init(void);
#ifdef CONFIG_SERIAL_8250
void __init sdv_serial_fixup(void);
#else
static inline void sdv_serial_fixup(void) {};
#endif
#endif

98
arch/x86/platform/ce4100/ce4100.c
View file

@ -5,19 +5,12 @@
* (C) Copyright 2010 Intel Corporation
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/irq.h>
#include <linux/reboot.h>
#include <linux/serial_reg.h>
#include <linux/serial_8250.h>
#include <asm/ce4100.h>
#include <asm/prom.h>
#include <asm/setup.h>
#include <asm/i8259.h>
#include <asm/io.h>
#include <asm/io_apic.h>
#include <asm/emergency-restart.h>
/*
* The CE4100 platform has an internal 8051 Microcontroller which is
@ -31,97 +24,6 @@ static void ce4100_power_off(void)
outb(0x4, 0xcf9);
}
#ifdef CONFIG_SERIAL_8250
static unsigned int mem_serial_in(struct uart_port *p, int offset)
{
offset = offset << p->regshift;
return readl(p->membase + offset);
}
/*
* The UART Tx interrupts are not set under some conditions and therefore serial
* transmission hangs. This is a silicon issue and has not been root caused. The
* workaround for this silicon issue checks UART_LSR_THRE bit and UART_LSR_TEMT
* bit of LSR register in interrupt handler to see whether at least one of these
* two bits is set, if so then process the transmit request. If this workaround
* is not applied, then the serial transmission may hang. This workaround is for
* errata number 9 in Errata - B step.
*/
static u32 ce4100_mem_serial_in(struct uart_port *p, unsigned int offset)
{
u32 ret, ier, lsr;
if (offset != UART_IIR)
return mem_serial_in(p, offset);
offset <<= p->regshift;
ret = readl(p->membase + offset);
if (!(ret & UART_IIR_NO_INT))
return ret;
/* see if the TX interrupt should have really set */
ier = mem_serial_in(p, UART_IER);
/* see if the UART's XMIT interrupt is enabled */
if (!(ier & UART_IER_THRI))
return ret;
lsr = mem_serial_in(p, UART_LSR);
/* now check to see if the UART should be generating an interrupt (but isn't) */
if (lsr & (UART_LSR_THRE | UART_LSR_TEMT))
ret &= ~UART_IIR_NO_INT;
return ret;
}
static void ce4100_mem_serial_out(struct uart_port *p, unsigned int offset, u32 value)
{
offset <<= p->regshift;
writel(value, p->membase + offset);
}
static void ce4100_serial_fixup(int port, struct uart_port *up,
u32 *capabilities)
{
#ifdef CONFIG_EARLY_PRINTK
/*
* Over ride the legacy port configuration that comes from
* asm/serial.h. Using the ioport driver then switching to the
* PCI memmaped driver hangs the IOAPIC
*/
if (up->iotype != UPIO_MEM32) {
up->uartclk = 14745600;
up->mapbase = 0xdffe0200;
set_fixmap_nocache(FIX_EARLYCON_MEM_BASE,
up->mapbase & PAGE_MASK);
up->membase =
(void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
up->membase += up->mapbase & ~PAGE_MASK;
up->mapbase += port * 0x100;
up->membase += port * 0x100;
up->iotype = UPIO_MEM32;
up->regshift = 2;
up->irq = 4;
}
#endif
up->iobase = 0;
up->serial_in = ce4100_mem_serial_in;
up->serial_out = ce4100_mem_serial_out;
*capabilities |= (1 << 12);
}
static __init void sdv_serial_fixup(void)
{
serial8250_set_isa_configurator(ce4100_serial_fixup);
}
#else
static inline void sdv_serial_fixup(void) {};
#endif
static void __init sdv_arch_setup(void)
{
sdv_serial_fixup();

98
drivers/tty/serial/8250/8250_ce4100.c Normal file
View file

@ -0,0 +1,98 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Intel CE4100 platform specific setup code
*
* (C) Copyright 2010 Intel Corporation
*/
#include <linux/init.h>
#include <linux/io.h>
#include <linux/types.h>
#include <asm/ce4100.h>
#include <asm/fixmap.h>
#include <asm/page.h>
#include <linux/serial_reg.h>
#include <linux/serial_8250.h>
static unsigned int mem_serial_in(struct uart_port *p, int offset)
{
offset = offset << p->regshift;
return readl(p->membase + offset);
}
/*
* The UART Tx interrupts are not set under some conditions and therefore serial
* transmission hangs. This is a silicon issue and has not been root caused. The
* workaround for this silicon issue checks UART_LSR_THRE bit and UART_LSR_TEMT
* bit of LSR register in interrupt handler to see whether at least one of these
* two bits is set, if so then process the transmit request. If this workaround
* is not applied, then the serial transmission may hang. This workaround is for
* errata number 9 in Errata - B step.
*/
static u32 ce4100_mem_serial_in(struct uart_port *p, unsigned int offset)
{
u32 ret, ier, lsr;
if (offset != UART_IIR)
return mem_serial_in(p, offset);
offset <<= p->regshift;
ret = readl(p->membase + offset);
if (!(ret & UART_IIR_NO_INT))
return ret;
/* see if the TX interrupt should have really set */
ier = mem_serial_in(p, UART_IER);
/* see if the UART's XMIT interrupt is enabled */
if (!(ier & UART_IER_THRI))
return ret;
lsr = mem_serial_in(p, UART_LSR);
/* now check to see if the UART should be generating an interrupt (but isn't) */
if (lsr & (UART_LSR_THRE | UART_LSR_TEMT))
ret &= ~UART_IIR_NO_INT;
return ret;
}
static void ce4100_mem_serial_out(struct uart_port *p, unsigned int offset, u32 value)
{
offset <<= p->regshift;
writel(value, p->membase + offset);
}
static void ce4100_serial_fixup(int port, struct uart_port *up, u32 *capabilities)
{
#ifdef CONFIG_EARLY_PRINTK
/*
* Override the legacy port configuration that comes from
* asm/serial.h. Using the ioport driver then switching to the
* PCI memmaped driver hangs the IOAPIC.
*/
if (up->iotype != UPIO_MEM32) {
up->uartclk = 14745600;
up->mapbase = 0xdffe0200;
set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, up->mapbase & PAGE_MASK);
up->membase = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
up->membase += up->mapbase & ~PAGE_MASK;
up->mapbase += port * 0x100;
up->membase += port * 0x100;
up->iotype = UPIO_MEM32;
up->regshift = 2;
up->irq = 4;
}
#endif
up->iobase = 0;
up->serial_in = ce4100_mem_serial_in;
up->serial_out = ce4100_mem_serial_out;
*capabilities |= (1 << 12);
}
void __init sdv_serial_fixup(void)
{
serial8250_set_isa_configurator(ce4100_serial_fixup);
}

1
drivers/tty/serial/8250/Makefile
View file

@ -24,6 +24,7 @@ obj-$(CONFIG_SERIAL_8250_ASPEED_VUART) += 8250_aspeed_vuart.o
obj-$(CONFIG_SERIAL_8250_BCM2835AUX) += 8250_bcm2835aux.o
obj-$(CONFIG_SERIAL_8250_BCM7271) += 8250_bcm7271.o
obj-$(CONFIG_SERIAL_8250_BOCA) += 8250_boca.o
obj-$(CONFIG_X86_INTEL_CE) += 8250_ce4100.o
obj-$(CONFIG_SERIAL_8250_DFL) += 8250_dfl.o
obj-$(CONFIG_SERIAL_8250_DW) += 8250_dw.o
obj-$(CONFIG_SERIAL_8250_EM) += 8250_em.o