diff options
Diffstat (limited to 'drivers/acpi/spcr.c')
| -rw-r--r-- | drivers/acpi/spcr.c | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c index 4ac3e06b41d8..98aa8c808a33 100644 --- a/drivers/acpi/spcr.c +++ b/drivers/acpi/spcr.c @@ -17,6 +17,16 @@ #include <linux/serial_core.h> /* + * Erratum 44 for QDF2432v1 and QDF2400v1 SoCs describes the BUSY bit as + * occasionally getting stuck as 1. To avoid the potential for a hang, check + * TXFE == 0 instead of BUSY == 1. This may not be suitable for all UART + * implementations, so only do so if an affected platform is detected in + * parse_spcr(). + */ +bool qdf2400_e44_present; +EXPORT_SYMBOL(qdf2400_e44_present); + +/* * 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. @@ -147,8 +157,30 @@ int __init parse_spcr(bool earlycon) goto done; } - if (qdf2400_erratum_44_present(&table->header)) - uart = "qdf2400_e44"; + /* + * If the E44 erratum is required, then we need to tell the pl011 + * driver to implement the work-around. + * + * The global variable is used by the probe function when it + * creates the UARTs, whether or not they're used as a console. + * + * If the user specifies "traditional" earlycon, the qdf2400_e44 + * console name matches the EARLYCON_DECLARE() statement, and + * SPCR is not used. Parameter "earlycon" is false. + * + * If the user specifies "SPCR" earlycon, then we need to update + * the console name so that it also says "qdf2400_e44". Parameter + * "earlycon" is true. + * + * For consistency, if we change the console name, then we do it + * for everyone, not just earlycon. + */ + if (qdf2400_erratum_44_present(&table->header)) { + qdf2400_e44_present = true; + if (earlycon) + uart = "qdf2400_e44"; + } + if (xgene_8250_erratum_present(table)) iotype = "mmio32"; |