In systems with ACPI support and when a DT is not provided, we can use the SPCR to discover the serial port address range. This change implements this but retains the default behavior; we check if a valid DT is provided, if not, we try to discover the UART using ACPI. Signed-off-by: Nikos Nikoleris <nikos.nikoleris@xxxxxxx> --- lib/acpi.h | 25 +++++++++++++++++++++++++ lib/arm/io.c | 21 +++++++++++++++++++-- 2 files changed, 44 insertions(+), 2 deletions(-) diff --git a/lib/acpi.h b/lib/acpi.h index 40392e3..0611cdf 100644 --- a/lib/acpi.h +++ b/lib/acpi.h @@ -16,6 +16,7 @@ #define XSDT_SIGNATURE ACPI_SIGNATURE('X','S','D','T') #define FACP_SIGNATURE ACPI_SIGNATURE('F','A','C','P') #define FACS_SIGNATURE ACPI_SIGNATURE('F','A','C','S') +#define SPCR_SIGNATURE ACPI_SIGNATURE('S','P','C','R') #define ACPI_SIGNATURE_8BYTE(c1, c2, c3, c4, c5, c6, c7, c8) \ @@ -147,6 +148,30 @@ struct facs_descriptor_rev1 u8 reserved3 [40]; /* Reserved - must be zero */ } __attribute__ ((packed)); +struct spcr_descriptor { + ACPI_TABLE_HEADER_DEF /* ACPI common table header */ + u8 interface_type; /* 0=full 16550, 1=subset of 16550 */ + u8 reserved[3]; + struct acpi_generic_address serial_port; + u8 interrupt_type; + u8 pc_interrupt; + u32 interrupt; + u8 baud_rate; + u8 parity; + u8 stop_bits; + u8 flow_control; + u8 terminal_type; + u8 reserved1; + u16 pci_device_id; + u16 pci_vendor_id; + u8 pci_bus; + u8 pci_device; + u8 pci_function; + u32 pci_flags; + u8 pci_segment; + u32 reserved2; +} __attribute__ ((packed)); + void set_efi_rsdp(struct rsdp_descriptor *rsdp); void* find_acpi_table_addr(u32 sig); diff --git a/lib/arm/io.c b/lib/arm/io.c index 343e108..893bdfc 100644 --- a/lib/arm/io.c +++ b/lib/arm/io.c @@ -8,6 +8,7 @@ * * This work is licensed under the terms of the GNU LGPL, version 2. */ +#include <acpi.h> #include <libcflat.h> #include <devicetree.h> #include <chr-testdev.h> @@ -29,7 +30,7 @@ static struct spinlock uart_lock; #define UART_EARLY_BASE (u8 *)(unsigned long)CONFIG_UART_EARLY_BASE static volatile u8 *uart0_base = UART_EARLY_BASE; -static void uart0_init(void) +static void uart0_init_fdt(void) { /* * kvm-unit-tests uses the uart only for output. Both uart models have @@ -73,9 +74,25 @@ static void uart0_init(void) } } +static void uart0_init_acpi(void) +{ + struct spcr_descriptor *spcr = find_acpi_table_addr(SPCR_SIGNATURE); + assert_msg(spcr, "Unable to find ACPI SPCR"); + uart0_base = ioremap(spcr->serial_port.address, spcr->serial_port.bit_width); + + if (uart0_base != UART_EARLY_BASE) { + printf("WARNING: early print support may not work. " + "Found uart at %p, but early base is %p.\n", + uart0_base, UART_EARLY_BASE); + } +} + void io_init(void) { - uart0_init(); + if (dt_available()) + uart0_init_fdt(); + else + uart0_init_acpi(); chr_testdev_init(); } -- 2.25.1