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authorGraeme Gregory <graeme.gregory@linaro.org>2017-08-05 00:49:44 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-08-16 19:16:46 +0300
commit03c3876f2e3b4c79ced7d1d227e5a7fe645ed666 (patch)
treec3b93f62cc094ec25e5189df287e7804ab4483fc /drivers/acpi
parentdee82bc1e653126408f4108cd994d1e96949d064 (diff)
downloadlinux-03c3876f2e3b4c79ced7d1d227e5a7fe645ed666.tar.xz
ACPI: SPCR: work around clock issue on xgene UART
xgene v1/v2 8250 UARTs don't run at the standard clock rate expected by the driver and there is no information on clocking available from the SPCR table. As there has been no progress on relevant vendors updating DBG2/SPCR specifications to fix this work around this using the previous xgene quirk handling to avoid setting a baud rate and therefore using the UART as configured by firmware. Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org> Tested-by: Mark Salter <msalter@redhat.com> Reviewed-by: Mark Salter <msalter@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/spcr.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
index 2c156941b371..40a56b538b9f 100644
--- a/drivers/acpi/spcr.c
+++ b/drivers/acpi/spcr.c
@@ -188,11 +188,19 @@ int __init parse_spcr(bool earlycon)
uart = "qdf2400_e44";
}
- if (xgene_8250_erratum_present(table))
+ if (xgene_8250_erratum_present(table)) {
iotype = "mmio32";
- snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
- table->serial_port.address, baud_rate);
+ /* for xgene v1 and v2 we don't know the clock rate of the
+ * UART so don't attempt to change to the baud rate state
+ * in the table because driver cannot calculate the dividers
+ */
+ snprintf(opts, sizeof(opts), "%s,%s,0x%llx", uart, iotype,
+ table->serial_port.address);
+ } else {
+ snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
+ table->serial_port.address, baud_rate);
+ }
pr_info("console: %s\n", opts);