Re: [PATCH 03/14] coresight: tmc: re-implementing tmc_read_prepare/unprepare() functions

From: Mathieu Poirier
Date: Thu Mar 24 2016 - 12:38:32 EST


On 23 March 2016 at 04:37, Suzuki K. Poulose <Suzuki.Poulose@xxxxxxx> wrote:
> On 22/03/16 20:23, Mathieu Poirier wrote:
>>
>> In their current implementation the tmc_read_prepare/unprepare()
>> are a lump of if/else that is difficult to read. This patch is
>> alleviating that by using a switch statement. The latter also
>> allows for a better control on the error path.
>>
>> Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
>> ---
>> drivers/hwtracing/coresight/coresight-tmc.c | 56
>> ++++++++++++++++++-----------
>> 1 file changed, 36 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc.c
>> b/drivers/hwtracing/coresight/coresight-tmc.c
>> index f4ba837a0810..208d47dd3083 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc.c
>> +++ b/drivers/hwtracing/coresight/coresight-tmc.c
>> @@ -430,7 +430,7 @@ static const struct coresight_ops tmc_etf_cs_ops = {
>>
>
>> - if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
>> + switch (drvdata->config_type) {
>> + case TMC_CONFIG_TYPE_ETB:
>> tmc_etb_disable_hw(drvdata);
>> - } else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
>> - tmc_etr_disable_hw(drvdata);
>> - } else {
>> + break;
>> + case TMC_CONFIG_TYPE_ETF:
>> + /* There is no point in reading a TMC in HW FIFO mode */
>> mode = readl_relaxed(drvdata->base + TMC_MODE);
>> - if (mode == TMC_MODE_CIRCULAR_BUFFER) {
>> - tmc_etb_disable_hw(drvdata);
>> - } else {
>> - ret = -ENODEV;
>> + if (mode != TMC_MODE_CIRCULAR_BUFFER) {
>> + ret = -EINVAL;
>> goto err;
>> }
>> +
>> + tmc_etb_disable_hw(drvdata);
>> + break;
>> + case TMC_CONFIG_TYPE_ETR:
>> + tmc_etr_disable_hw(drvdata);
>> + break;
>> + default:
>> + ret = -EINVAL;
>> + goto err;
>> }
>
>
> We seem to be doing this switch at different places in the code just for
> enable_hw/disable_hw.
> e.g, tmc_enable, tmc_disable
>
> Could we make this a bit more cleaner by introducing something like this ?
>
> struct tmc_hw_ops {
> int (*enable_hw)(struct tmc_drvdata *drvdata, enum tmc_mode mode);
> int (*disable_hw)(struct tmc_drvdata *drvdata, enum tmc_mode mode);
> };
>
> struct tmc_hw_ops tmc_etf_ops = {
> tmc_etf_enable_hw,
> tmc_etf_disable_hw,
> };
>
> similiarly for etb and etr and then add struct tmc_hw_ops *hw_ops to
> tmc_drvdata, initialised
> at probe time (while reading the config_type).

That is a good idea - let me experiment with it a little...

>
>
> Suzuki
>