Currently, when a sensor value is read, the kernel calls OPAL, which in turn builds a message for the FSP, and waits for a message back.
The new device tree for OPAL sensors [1] adds new sensors that can be read synchronously (core temperatures for instance) and that don't need to wait for a response. This patch modifies the opal call to accept an OPAL_SUCCESS return value and cover the case above. [1] https://lists.ozlabs.org/pipermail/skiboot/2015-March/000639.html Signed-off-by: Cédric Le Goater <c...@fr.ibm.com> --- We still uselessly reserve a token (for the response) and take a lock, which might raise the need of a new 'opal_sensor_read_sync' call. Changes since v2 : - merged the return code assignments in one call arch/powerpc/platforms/powernv/opal-sensor.c | 32 ++++++++++++++++----------- 1 file changed, 20 insertions(+), 12 deletions(-) Index: linux.git/arch/powerpc/platforms/powernv/opal-sensor.c =================================================================== --- linux.git.orig/arch/powerpc/platforms/powernv/opal-sensor.c +++ linux.git/arch/powerpc/platforms/powernv/opal-sensor.c @@ -46,20 +46,28 @@ int opal_get_sensor_data(u32 sensor_hndl mutex_lock(&opal_sensor_mutex); ret = opal_sensor_read(sensor_hndl, token, &data); - if (ret != OPAL_ASYNC_COMPLETION) { - ret = opal_error_code(ret); - goto out_token; - } + switch (ret) { + case OPAL_ASYNC_COMPLETION: + ret = opal_async_wait_response(token, &msg); + if (ret) { + pr_err("%s: Failed to wait for the async response, %d\n", + __func__, ret); + goto out_token; + } - ret = opal_async_wait_response(token, &msg); - if (ret) { - pr_err("%s: Failed to wait for the async response, %d\n", - __func__, ret); - goto out_token; - } + ret = opal_error_code(be64_to_cpu(msg.params[1])); + *sensor_data = be32_to_cpu(data); + break; - *sensor_data = be32_to_cpu(data); - ret = opal_error_code(be64_to_cpu(msg.params[1])); + case OPAL_SUCCESS: + ret = 0; + *sensor_data = be32_to_cpu(data); + break; + + default: + ret = opal_error_code(ret); + break; + } out_token: mutex_unlock(&opal_sensor_mutex); _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
