diff options
| author | Tim Chu <Tim.Chu@quantatw.com> | 2022-10-19 06:24:21 +0000 |
|---|---|---|
| committer | Felix Held <felix-coreboot@felixheld.de> | 2022-10-25 15:12:36 +0000 |
| commit | e27e1c1c6389e0a4d87c97dfef14068bfc7ddde6 (patch) | |
| tree | d1b6a69811df70b8f2ec0a66434d489de5050e27 | |
| parent | 5e5335da685482bc790fffe22f1b9aab6e416248 (diff) | |
soc/intel/xeon_sp: Add functions to store/restore uart state in smm
When CONFIG_DEBUG_SMI is enabled SMM handler performs console hardware
initialization that may interfere with OS. Here we store the state
before console initialization and restore state before SMM exit.
Tested=On not public yet system, after exiting smm, uart console can
still work well.
Signed-off-by: Tim Chu <Tim.Chu@quantatw.com>
Change-Id: Ifa5042c24f0e3217a75971d9e6067b1d1f56a484
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68567
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jonathan Zhang <jonzhang@fb.com>
| -rw-r--r-- | src/soc/intel/xeon_sp/smihandler.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/src/soc/intel/xeon_sp/smihandler.c b/src/soc/intel/xeon_sp/smihandler.c index 1c04b95d73..d644447aee 100644 --- a/src/soc/intel/xeon_sp/smihandler.c +++ b/src/soc/intel/xeon_sp/smihandler.c @@ -1,12 +1,55 @@ /* SPDX-License-Identifier: GPL-2.0-only */ +#include <arch/io.h> #include <console/console.h> +#include <console/uart.h> #include <cpu/x86/smm.h> #include <device/pci.h> +#include <drivers/uart/uart8250reg.h> #include <intelblocks/smihandler.h> #include <soc/pci_devs.h> #include <soc/pm.h> +struct uart8250_state { + uint8_t IER, IIR, MCR, LCR, DLL, DLM; +}; + +static struct uart8250_state s_uart8250_state; + +static void uart8250_store(unsigned int base_port) +{ + /* Save previous state for restoring later. */ + s_uart8250_state.IER = inb(base_port + UART8250_IER); + s_uart8250_state.IIR = inb(base_port + UART8250_FCR); + s_uart8250_state.MCR = inb(base_port + UART8250_MCR); + s_uart8250_state.LCR = inb(base_port + UART8250_LCR); + s_uart8250_state.DLL = inb(base_port + UART8250_DLL); + s_uart8250_state.DLM = inb(base_port + UART8250_DLM); +} + +void smm_soc_early_init(void) +{ + if (CONFIG(DRIVERS_UART_8250IO) && CONFIG(DEBUG_SMI)) + uart8250_store(uart_platform_base(CONFIG_UART_FOR_CONSOLE)); +} + +static void uart8250_restore(unsigned int base_port) +{ + outb(s_uart8250_state.DLL, base_port + UART8250_DLL); + outb(s_uart8250_state.DLM, base_port + UART8250_DLM); + outb(s_uart8250_state.MCR, base_port + UART8250_MCR); + outb(s_uart8250_state.LCR, base_port + UART8250_LCR); + if ((s_uart8250_state.IIR & UART8250_IIR_FIFO_EN) == UART8250_IIR_FIFO_EN) + outb(UART8250_FCR_FIFO_EN, base_port + UART8250_FCR); + outb(s_uart8250_state.IER, base_port + UART8250_IER); +} + +void smm_soc_exit(void) +{ + if (CONFIG(DRIVERS_UART_8250IO) && CONFIG(DEBUG_SMI)) + uart8250_restore(uart_platform_base(CONFIG_UART_FOR_CONSOLE)); +} + /* * Specific SOC SMI handler during ramstage finalize phase */ |