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struct uart_8250_port contains mcr_mask and mcr_force members whose sole purpose is to work around an Alpha-specific quirk. This code doesn't belong in the core where it is executed by everyone else, so move it to a proper ->set_mctrl callback which is used on the affected Alpha machine only. The quirk was introduced in January 1995: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/diff/drivers/char/serial.c?h=1.1.83 The members in struct uart_8250_port were added in 2002: https://git.kernel.org/history/history/c/4524aad27854 The quirk applies to non-PCI Alphas and arch/alpha/Kconfig specifies "select FORCE_PCI if !ALPHA_JENSEN". So apparently the only affected machine is the EISA-based Jensen that Linus was working on back then: https://lore.kernel.org/all/CAHk-=wj1JWZ3sCrGz16nxEj7=0O+srMg6Ah3iPTDXSPKEws_SA@mail.gmail.com/ Up until now the quirk is not applied unless CONFIG_PCI is disabled. If users forget to do that or run a generic Alpha kernel, the serial ports aren't usable on Jensen. Avoid by confining the quirk to CONFIG_ALPHA_JENSEN instead of !CONFIG_PCI. On generic Alpha kernels, auto-detect at runtime whether the quirk needs to be applied. Cc: Russell King <rmk+kernel@armlinux.org.uk> Cc: Ulrich Teichert <krypton@ulrich-teichert.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Lukas Wunner <lukas@wunner.de> Link: https://lore.kernel.org/r/b83d069cb516549b8a5420e097bb6bdd806f36fc.1640695609.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
22 lines
516 B
C
22 lines
516 B
C
// SPDX-License-Identifier: GPL-2.0+
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#include <asm/machvec.h>
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#include "8250.h"
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bool alpha_jensen(void)
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{
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return !strcmp(alpha_mv.vector_name, "Jensen");
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}
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void alpha_jensen_set_mctrl(struct uart_port *port, unsigned int mctrl)
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{
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/*
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* Digital did something really horribly wrong with the OUT1 and OUT2
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* lines on Alpha Jensen. The failure mode is that if either is
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* cleared, the machine locks up with endless interrupts.
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*/
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mctrl |= TIOCM_OUT1 | TIOCM_OUT2;
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serial8250_do_set_mctrl(port, mctrl);
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}
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