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path: root/drivers/acpi/spcr.c
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Diffstat (limited to 'drivers/acpi/spcr.c')
-rw-r--r--drivers/acpi/spcr.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
index b8019c4c1d38..2b5d0fac81f0 100644
--- a/drivers/acpi/spcr.c
+++ b/drivers/acpi/spcr.c
@@ -16,6 +16,26 @@
#include <linux/kernel.h>
#include <linux/serial_core.h>
+/*
+ * Some Qualcomm Datacenter Technologies SoCs have a defective UART BUSY bit.
+ * Detect them by examining the OEM fields in the SPCR header, similiar to PCI
+ * quirk detection in pci_mcfg.c.
+ */
+static bool qdf2400_erratum_44_present(struct acpi_table_header *h)
+{
+ if (memcmp(h->oem_id, "QCOM ", ACPI_OEM_ID_SIZE))
+ return false;
+
+ if (!memcmp(h->oem_table_id, "QDF2432 ", ACPI_OEM_TABLE_ID_SIZE))
+ return true;
+
+ if (!memcmp(h->oem_table_id, "QDF2400 ", ACPI_OEM_TABLE_ID_SIZE) &&
+ h->oem_revision == 0)
+ return true;
+
+ return false;
+}
+
/**
* parse_spcr() - parse ACPI SPCR table and add preferred console
*
@@ -93,6 +113,9 @@ int __init parse_spcr(bool earlycon)
goto done;
}
+ if (qdf2400_erratum_44_present(&table->header))
+ uart = "qdf2400_e44";
+
snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
table->serial_port.address, baud_rate);