@@ -77,6 +77,9 @@ config ACPI_DEBUGGER_USER
endif
+config ACPI_SPCR_TABLE
+ bool
+
config ACPI_SLEEP
bool
depends on SUSPEND || HIBERNATION
@@ -82,6 +82,7 @@ obj-$(CONFIG_ACPI_EC_DEBUGFS) += ec_sys.o
obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
obj-$(CONFIG_ACPI_BGRT) += bgrt.o
obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o
+obj-$(CONFIG_ACPI_SPCR_TABLE) += spcr.o
obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o
# processor has its own "processor." module_param namespace
new file mode 100644
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2012, Intel Corporation
+ * Copyright (c) 2015, Red Hat, Inc.
+ * Copyright (c) 2015, 2016 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#define pr_fmt(fmt) "ACPI: SPCR: " fmt
+
+#include <linux/acpi.h>
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/serial_core.h>
+
+static bool init_earlycon;
+
+void __init init_spcr_earlycon(void)
+{
+ init_earlycon = true;
+}
+
+int __init parse_spcr(void)
+{
+ static char opts[64];
+ struct acpi_table_spcr *table;
+ acpi_size table_size;
+ acpi_status status;
+ char *uart;
+ char *iotype;
+ int baud_rate;
+ int err = 0;
+
+ status = acpi_get_table_with_size(ACPI_SIG_SPCR, 0,
+ (struct acpi_table_header **)&table,
+ &table_size);
+
+ if (ACPI_FAILURE(status))
+ return -ENOENT;
+
+ if (table->header.revision < 2) {
+ err = -EINVAL;
+ pr_err("wrong table version\n");
+ goto done;
+ }
+
+ iotype = (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) ?
+ "mmio" : "io";
+
+ switch (table->interface_type) {
+ case ACPI_DBG2_ARM_SBSA_32BIT:
+ iotype = "mmio32";
+ /* fall through */
+ case ACPI_DBG2_ARM_PL011:
+ case ACPI_DBG2_ARM_SBSA_GENERIC:
+ case ACPI_DBG2_BCM2835:
+ uart = "pl011";
+ break;
+ case ACPI_DBG2_16550_COMPATIBLE:
+ case ACPI_DBG2_16550_SUBSET:
+ uart = "uart";
+ break;
+ default:
+ err = -ENOENT;
+ goto done;
+ }
+
+ switch (table->baud_rate) {
+ case 3:
+ baud_rate = 9600;
+ break;
+ case 4:
+ baud_rate = 19200;
+ break;
+ case 6:
+ baud_rate = 57600;
+ break;
+ case 7:
+ baud_rate = 115200;
+ break;
+ default:
+ err = -ENOENT;
+ goto done;
+ }
+
+ sprintf(opts, "%s,%s,0x%llx,%d", uart, iotype,
+ table->serial_port.address, baud_rate);
+
+ pr_info("console: %s", opts);
+
+ if (init_earlycon)
+ setup_earlycon(opts);
+
+ err = add_preferred_console(uart, 0, opts + strlen(uart) + 1);
+
+done:
+ early_acpi_os_unmap_memory((void __iomem *)table, table_size);
+ return err;
+}
@@ -22,6 +22,7 @@
#include <linux/sizes.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
+#include <linux/acpi.h>
#ifdef CONFIG_FIX_EARLYCON_MEM
#include <asm/fixmap.h>
@@ -206,11 +207,15 @@ static int __init param_setup_earlycon(char *buf)
int err;
/*
- * Just 'earlycon' is a valid param for devicetree earlycons;
- * don't generate a warning from parse_early_params() in that case
+ * Just 'earlycon' is a valid param for devicetree and ACPI SPCR
+ * earlycons; don't generate a warning from parse_early_params()
+ * in that case
*/
- if (!buf || !buf[0])
- return early_init_dt_scan_chosen_serial();
+ if (!buf || !buf[0]) {
+ init_spcr_earlycon();
+ early_init_dt_scan_chosen_serial();
+ return 0;
+ }
err = setup_earlycon(buf);
if (err == -ENOENT || err == -EALREADY)
@@ -1004,4 +1004,12 @@ static inline struct fwnode_handle *acpi_get_next_subnode(struct device *dev,
#define acpi_probe_device_table(t) ({ int __r = 0; __r;})
#endif
+#ifdef CONFIG_ACPI_SPCR_TABLE
+int parse_spcr(void);
+void init_spcr_earlycon(void);
+#else
+static inline int parse_spcr(void) { return 0; }
+static inline void init_spcr_earlycon(void) {}
+#endif
+
#endif /*_LINUX_ACPI_H*/
'ARM Server Base Boot Requiremets' [1] mentions SPCR (Serial Port Console Redirection Table) [2] as a mandatory ACPI table that specifies the configuration of serial console. Parse this table, setup earlycon and enable the specified console. Thanks to Peter Hurley for explaining how this should work. [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0044a/index.html [2] https://msdn.microsoft.com/en-us/library/windows/hardware/dn639132(v=vs.85).aspx Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org> --- drivers/acpi/Kconfig | 3 ++ drivers/acpi/Makefile | 1 + drivers/acpi/spcr.c | 102 ++++++++++++++++++++++++++++++++++++++++++ drivers/tty/serial/earlycon.c | 13 ++++-- include/linux/acpi.h | 8 ++++ 5 files changed, 123 insertions(+), 4 deletions(-) create mode 100644 drivers/acpi/spcr.c -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html