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

From: Mathieu Poirier
Date: Tue Mar 22 2016 - 16:23:59 EST


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 = {

static int tmc_read_prepare(struct tmc_drvdata *drvdata)
{
- int ret;
+ int ret = 0;
unsigned long flags;
enum tmc_mode mode;

@@ -438,25 +438,31 @@ static int tmc_read_prepare(struct tmc_drvdata *drvdata)
if (!drvdata->enable)
goto out;

- 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;
}
+
out:
drvdata->reading = true;
- spin_unlock_irqrestore(&drvdata->spinlock, flags);
-
dev_info(drvdata->dev, "TMC read start\n");
- return 0;
err:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
return ret;
@@ -471,20 +477,30 @@ static void tmc_read_unprepare(struct tmc_drvdata *drvdata)
if (!drvdata->enable)
goto out;

- if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
+ switch (drvdata->config_type) {
+ case TMC_CONFIG_TYPE_ETB:
tmc_etb_enable_hw(drvdata);
- } else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
- tmc_etr_enable_hw(drvdata);
- } else {
+ break;
+ case TMC_CONFIG_TYPE_ETF:
+ /* Make sure we don't re-enable a TMC in HW FIFO mode */
mode = readl_relaxed(drvdata->base + TMC_MODE);
- if (mode == TMC_MODE_CIRCULAR_BUFFER)
- tmc_etb_enable_hw(drvdata);
+ if (mode != TMC_MODE_CIRCULAR_BUFFER)
+ goto err;
+
+ tmc_etb_enable_hw(drvdata);
+ break;
+ case TMC_CONFIG_TYPE_ETR:
+ tmc_etr_disable_hw(drvdata);
+ break;
+ default:
+ goto err;
}
+
out:
drvdata->reading = false;
- spin_unlock_irqrestore(&drvdata->spinlock, flags);
-
dev_info(drvdata->dev, "TMC read end\n");
+err:
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
}

static int tmc_open(struct inode *inode, struct file *file)
--
2.1.4