[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v2 2/3] term/serial: Add support for PCI serial devices
From: |
Glenn Washburn |
Subject: |
Re: [PATCH v2 2/3] term/serial: Add support for PCI serial devices |
Date: |
Fri, 26 Aug 2022 13:32:25 -0500 |
On Fri, 26 Aug 2022 13:01:44 +0200
peterz@infradead.org wrote:
> 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"
Forgive my ignorance, I'm a bit confused why the above line does not
work without the patch, or does it? Is it because the line
"grub_pci_write (cmd_addr, cmdreg | GRUB_PCI_COMMAND_IO_ENABLED);" was
needed to enable that IO port?
Either way, I think it would be better to example would be something
like:
GRUB_SERIAL_COMMAND="serial --speed=115200 pci0"
Otherwise, LGTM.
Reviewed-by: Glenn Washburn <development@efficientek.com>
Glenn
> GRUB_TERMINAL="serial console"
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
>
> Index: grub/grub-core/Makefile.core.def
> ===================================================================
> --- grub.orig/grub-core/Makefile.core.def
> +++ grub/grub-core/Makefile.core.def
> @@ -2047,6 +2047,7 @@ module = {
> ieee1275 = term/ieee1275/serial.c;
> mips_arc = term/arc/serial.c;
> efi = term/efi/serial.c;
> + pci = term/pci/serial.c;
>
> enable = terminfomodule;
> enable = ieee1275;
> Index: grub/grub-core/term/pci/serial.c
> ===================================================================
> --- /dev/null
> +++ grub/grub-core/term/pci/serial.c
> @@ -0,0 +1,95 @@
> +/*
> + * GRUB -- GRand Unified Bootloader
> + * Copyright (C) 2022 Free Software Foundation, Inc.
> + *
> + * GRUB is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 3 of the License, or
> + * (at your option) any later version.
> + *
> + * GRUB is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <grub/serial.h>
> +#include <grub/term.h>
> +#include <grub/types.h>
> +#include <grub/pci.h>
> +#include <grub/mm.h>
> +#include <grub/misc.h>
> +
> +static int
> +find_pciserial (grub_pci_device_t dev, grub_pci_id_t pciid, void *data)
> +{
> + grub_pci_address_t cmd_addr, class_addr, bar_addr;
> + struct grub_serial_port *port;
> + grub_uint32_t class, bar;
> + grub_uint16_t cmdreg;
> + int *port_num = data;
> + grub_err_t err;
> +
> + (void)pciid;
> +
> + cmd_addr = grub_pci_make_address (dev, GRUB_PCI_REG_COMMAND);
> + cmdreg = grub_pci_read (cmd_addr);
> +
> + class_addr = grub_pci_make_address (dev, GRUB_PCI_REG_REVISION);
> + class = grub_pci_read (class_addr);
> +
> + bar_addr = grub_pci_make_address (dev, GRUB_PCI_REG_ADDRESS_REG0);
> + bar = grub_pci_read (bar_addr);
> +
> + /* 16550 compattible MODEM or SERIAL */
> + if (((class >> 16) != GRUB_PCI_CLASS_COMMUNICATION_MODEM &&
> + (class >> 16) != GRUB_PCI_CLASS_COMMUNICATION_SERIAL) ||
> + ((class >> 8) & 0xff) != GRUB_PCI_SERIAL_16550_COMPATIBLE)
> + return 0;
> +
> + if ((bar & GRUB_PCI_ADDR_SPACE_MASK) != GRUB_PCI_ADDR_SPACE_IO)
> + return 0;
> +
> + port = grub_zalloc (sizeof (*port));
> + if (port == NULL)
> + return 0;
> +
> + port->name = grub_xasprintf ("pci%d", (*port_num));
> + if (port->name == NULL)
> + goto error;
> +
> + grub_pci_write (cmd_addr, cmdreg | GRUB_PCI_COMMAND_IO_ENABLED);
> +
> + port->driver = &grub_ns8250_driver;
> + port->port = bar & GRUB_PCI_ADDR_IO_MASK;
> + err = grub_serial_config_defaults (port);
> + if (err != GRUB_ERR_NONE)
> + {
> + grub_print_error ();
> + goto error;
> + }
> +
> + err = grub_serial_register (port);
> + if (err != GRUB_ERR_NONE)
> + goto error;
> +
> + (*port_num)++;
> +
> + return 0;
> +
> +error:
> + grub_free (port->name);
> + grub_free (port);
> + return 0;
> +}
> +
> +void
> +grub_pciserial_init (void)
> +{
> + int port_num;
> +
> + grub_pci_iterate (find_pciserial, &port_num);
> +}
> Index: grub/grub-core/term/serial.c
> ===================================================================
> --- grub.orig/grub-core/term/serial.c
> +++ grub/grub-core/term/serial.c
> @@ -448,6 +448,9 @@ GRUB_MOD_INIT(serial)
> #ifdef GRUB_MACHINE_ARC
> grub_arcserial_init ();
> #endif
> +#ifdef GRUB_HAS_PCI
> + grub_pciserial_init ();
> +#endif
> }
>
> GRUB_MOD_FINI(serial)
> Index: grub/include/grub/pci.h
> ===================================================================
> --- grub.orig/include/grub/pci.h
> +++ grub/include/grub/pci.h
> @@ -80,8 +80,13 @@
>
> #define GRUB_PCI_STATUS_DEVSEL_TIMING_SHIFT 9
> #define GRUB_PCI_STATUS_DEVSEL_TIMING_MASK 0x0600
> +
> #define GRUB_PCI_CLASS_SUBCLASS_VGA 0x0300
> #define GRUB_PCI_CLASS_SUBCLASS_USB 0x0c03
> +#define GRUB_PCI_CLASS_COMMUNICATION_SERIAL 0x0700
> +#define GRUB_PCI_CLASS_COMMUNICATION_MODEM 0x0703
> +
> +#define GRUB_PCI_SERIAL_16550_COMPATIBLE 0x02
>
> #ifndef ASM_FILE
>
> Index: grub/include/grub/serial.h
> ===================================================================
> --- grub.orig/include/grub/serial.h
> +++ grub/include/grub/serial.h
> @@ -193,6 +193,10 @@ const char *
> grub_arcserial_add_port (const char *path);
> #endif
>
> +#ifdef GRUB_HAS_PCI
> +void grub_pciserial_init (void);
> +#endif
> +
> struct grub_serial_port *grub_serial_find (const char *name);
> extern struct grub_serial_driver grub_ns8250_driver;
> void EXPORT_FUNC(grub_serial_unregister_driver) (struct grub_serial_driver
> *driver);
>
>