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Peter Zijlstra (Intel)
8eb3d4df3f
Loosely based on early_pci_serial_init() from Linux, allow GRUB to make
use of PCI serial devices.
Specifically, my Alderlake NUC exposes the Intel AMT SoL UART as a PCI
enumerated device but doesn't include it in the EFI tables.
Tested and confirmed working on a "Lenovo P360 Tiny" with Intel AMT
enabled. This specific machine has (from lspci -vv):
00:16.3 Serial controller: Intel Corporation Device 7aeb (rev 11) (prog-if 02 [16550])
DeviceName: Onboard - Other
Subsystem: Lenovo Device 330e
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Interrupt: pin D routed to IRQ 19
Region 0: I/O ports at 40a0 [size=8]
Region 1: Memory at b4224000 (32-bit, non-prefetchable) [size=4K]
Capabilities: [40] MSI: Enable- Count=1/1 Maskable- 64bit+
Address: 0000000000000000 Data: 0000
Capabilities: [50] Power Management version 3
Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
Kernel driver in use: serial
From which the following config (/etc/default/grub) gets a working
serial setup:
GRUB_CMDLINE_LINUX="console=tty0 earlyprintk=pciserial,00:16.3,115200 console=ttyS0,115200"
GRUB_SERIAL_COMMAND="serial --port=0x40a0 --speed=115200"
GRUB_TERMINAL="serial console"
Documentation is added to note that serial devices found on the PCI bus will
be exposed as "pci,XX:XX.X" and how to find serial terminal logical names.
Also, some minor documentation improvements were added.
This can be tested in QEMU by adding a pci-serial device, e.g. using the option
"-device pci-serial".
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Glenn Washburn <development@efficientek.com>
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
92 lines
2.5 KiB
C
92 lines
2.5 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2023 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/serial.h>
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#include <grub/term.h>
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#include <grub/types.h>
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#include <grub/pci.h>
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#include <grub/mm.h>
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#include <grub/misc.h>
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static int
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find_pciserial (grub_pci_device_t dev, grub_pci_id_t pciid __attribute__ ((unused)), void *data __attribute__ ((unused)))
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{
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grub_pci_address_t cmd_addr, class_addr, bar_addr;
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struct grub_serial_port *port;
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grub_uint32_t class, bar;
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grub_uint16_t cmdreg;
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grub_err_t err;
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cmd_addr = grub_pci_make_address (dev, GRUB_PCI_REG_COMMAND);
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cmdreg = grub_pci_read (cmd_addr);
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class_addr = grub_pci_make_address (dev, GRUB_PCI_REG_REVISION);
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class = grub_pci_read (class_addr);
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bar_addr = grub_pci_make_address (dev, GRUB_PCI_REG_ADDRESS_REG0);
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bar = grub_pci_read (bar_addr);
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/* 16550 compatible MODEM or SERIAL. */
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if (((class >> 16) != GRUB_PCI_CLASS_COMMUNICATION_MODEM &&
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(class >> 16) != GRUB_PCI_CLASS_COMMUNICATION_SERIAL) ||
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((class >> 8) & 0xff) != GRUB_PCI_SERIAL_16550_COMPATIBLE)
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return 0;
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if ((bar & GRUB_PCI_ADDR_SPACE_MASK) != GRUB_PCI_ADDR_SPACE_IO)
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return 0;
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port = grub_zalloc (sizeof (*port));
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if (port == NULL)
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return 0;
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port->name = grub_xasprintf ("pci,%02x:%02x.%x",
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grub_pci_get_bus (dev),
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grub_pci_get_device (dev),
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grub_pci_get_function (dev));
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if (port->name == NULL)
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goto fail;
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grub_pci_write (cmd_addr, cmdreg | GRUB_PCI_COMMAND_IO_ENABLED);
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port->driver = &grub_ns8250_driver;
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port->port = bar & GRUB_PCI_ADDR_IO_MASK;
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err = grub_serial_config_defaults (port);
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if (err != GRUB_ERR_NONE)
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{
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grub_print_error ();
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goto fail;
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}
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err = grub_serial_register (port);
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if (err != GRUB_ERR_NONE)
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goto fail;
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return 0;
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fail:
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grub_free (port->name);
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grub_free (port);
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return 0;
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}
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void
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grub_pciserial_init (void)
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{
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grub_pci_iterate (find_pciserial, NULL);
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}
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