On Fri, May 06, 2022 at 09:55:48PM +0100, Nikos Nikoleris wrote:
> 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 +++++++++++++++++++--
> lib/arm/psci.c | 4 +++-
> 3 files changed, 47 insertions(+), 3 deletions(-)
>
> diff --git a/lib/acpi.h b/lib/acpi.h
> index 139ccba..5213299 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();
> }
>
> diff --git a/lib/arm/psci.c b/lib/arm/psci.c
> index 0e96d19..afbc33d 100644
> --- a/lib/arm/psci.c
> +++ b/lib/arm/psci.c
> @@ -80,9 +80,11 @@ static void psci_set_conduit_fdt(void)
> static void psci_set_conduit_acpi(void)
> {
> struct acpi_table_fadt *fadt = find_acpi_table_addr(FACP_SIGNATURE);
> +
> assert_msg(fadt, "Unable to find ACPI FADT");
> assert_msg(fadt->arm_boot_flags & ACPI_FADT_PSCI_COMPLIANT,
> - "PSCI is not supported in this platfrom");
> + "PSCI is not supported in this platform");
> +
> if (fadt->arm_boot_flags & ACPI_FADT_PSCI_USE_HVC)
> psci_invoke = psci_invoke_hvc;
> else
> --
> 2.25.1
>
Reviewed-by: Ricardo Koller <ricarkol@xxxxxxxxxx>
