On Wed, Feb 15, 2017 at 07:50:27PM +0000, Mark Rutland wrote: > On Wed, Feb 15, 2017 at 01:01:59PM -0500, Christopher Covington wrote: > > The Qualcomm Datacenter Technologies QDF2400 family of SoCs contains a > > custom (non-PrimeCell) implementation of the SBSA UART. Occasionally the > > BUSY bit in the Flag Register gets stuck as 1, erratum 44 for both 2432v1 > > and 2400v1 SoCs.Checking that the Transmit FIFO Empty (TXFE) bit is 0, > > instead of checking that the BUSY bit is 1, works around the issue. > > > > To facilitate this substitution of flags and values, introduce > > vendor-specific inversion of Feature Register bits when UART AMBA Port > > (UAP) data is available. For the earlycon case, prior to UAP availability, > > implement alternative putc and early_write functions. > > > > Similar to what how ARMv8 ACPI PCI quirks are detected during MCFG parsing, > > check the OEM fields of the Serial Port Console Redirection (SPCR) ACPI > > table to determine if the current platform is known to be affected by the > > erratum. > > > > Signed-off-by: Christopher Covington <cov@xxxxxxxxxxxxxx> > > Acked-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx> > > --- > > Since v2: Formatting and other improvements per Timur's suggestions > > Due to known (although trivial) conflicts in silicon-errata.txt, based on > > http://git.kernel.org/cgit/linux/kernel/git/arm64/linux.git/log/?h=for-next/core > > --- > > Documentation/arm64/silicon-errata.txt | 2 ++ > > drivers/acpi/spcr.c | 23 ++++++++++++ > > drivers/tty/serial/amba-pl011.c | 66 ++++++++++++++++++++++++++++++---- > > 3 files changed, 84 insertions(+), 7 deletions(-) > > > > diff --git a/Documentation/arm64/silicon-errata.txt b/Documentation/arm64/silicon-errata.txt > > index a71b8095dbd8..bc3d086bc624 100644 > > --- a/Documentation/arm64/silicon-errata.txt > > +++ b/Documentation/arm64/silicon-errata.txt > > @@ -68,3 +68,5 @@ stable kernels. > > | | | | | > > | Qualcomm Tech. | Falkor v1 | E1003 | QCOM_FALKOR_ERRATUM_1003 | > > | Qualcomm Tech. | Falkor v1 | E1009 | QCOM_FALKOR_ERRATUM_1009 | > > +| Qualcomm Tech. | QDF2432v1 UART | SoC E44 | N/A | > > +| Qualcomm Tech. | QDF2400v1 UART | SoC E44 | N/A | > > 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"; > > + > > This addresses my concern with using the MIDR; thanks for respinning > this. FWIW: > > Acked-by: Mark Rutland <mark.rutland@xxxxxxx> > > It might be best to split the silicon-errata doc into a separate patch. > That can go via the arm64 tree without conflict whiel the driver patch > can go via the tty tree. Well, I can't take this as-is because I get conflicts in my tty tree with the doc, and with the driver itself: checking file Documentation/arm64/silicon-errata.txt Hunk #1 FAILED at 68. 1 out of 1 hunk FAILED checking file drivers/acpi/spcr.c checking file drivers/tty/serial/amba-pl011.c Hunk #5 FAILED at 2370. 1 out of 8 hunks FAILED I have no idea what the driver conflict is, what branch was this made against? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
