[PATCH V2 8/9] spi: bcm2835aux: add driver stats to debugfs

kernel
2019-03-24T17:52:21Z

To estimate efficiency add statistics on transfer types
(polling and interrupt) used to debugfs.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
---
drivers/spi/spi-bcm2835aux.c | 61 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)

diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index dd0446968da6..d2b58060b333 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -21,6 +21,7 @@

#include <linux/clk.h>
#include <linux/completion.h>
+#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
@@ -102,8 +103,57 @@ struct bcm2835aux_spi {
int tx_len;
int rx_len;
int pending;
+
+#if defined(CONFIG_DEBUG_FS)
+#define BCM2835_AUX_INCR(field) ((field)++)
+ u64 count_transfer_polling;
+ u64 count_transfer_irq;
+ u64 count_transfer_irq_after_poll;
+
+ struct dentry *debugfs_dir;
+#else
+#define BCM2835_AUX_INCR(field)
+#endif /* CONFIG_DEBUG_FS */
};

+#if defined(CONFIG_DEBUG_FS)
+static void bcm2835aux_debugfs_create(struct bcm2835aux_spi *bs,
+ const char *dname)
+{
+ char name[64];
+ struct dentry *dir;
+
+ /* get full name */
+ snprintf(name, sizeof(name), "spi-bcm2835aux-%s", dname);
+
+ /* the base directory */
+ dir = debugfs_create_dir(name, NULL);
+ bs->debugfs_dir = dir;
+
+ /* the counters */
+ debugfs_create_u64("count_transfer_polling", 0444, dir,
+ &bs->count_transfer_polling);
+ debugfs_create_u64("count_transfer_irq", 0444, dir,
+ &bs->count_transfer_irq);
+ debugfs_create_u64("count_transfer_irq_after_poll", 0444, dir,
+ &bs->count_transfer_irq_after_poll);
+}
+
+static void bcm2835aux_debugfs_remove(struct bcm2835aux_spi *bs)
+{
+ debugfs_remove_recursive(bs->debugfs_dir);
+ bs->debugfs_dir = NULL;
+}
+#else
+static void bcm2835aux_debugfs_create(struct bcm2835aux_spi *bs)
+{
+}
+
+static void bcm2835aux_debugfs_remove(struct bcm2835aux_spi *bs)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
static inline u32 bcm2835aux_rd(struct bcm2835aux_spi *bs, unsigned reg)
{
return readl(bs->regs + reg);
@@ -242,6 +292,9 @@ static int bcm2835aux_spi_transfer_one_irq(struct spi_master *master,
{
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);

+ /* update statistics */
+ BCM2835_AUX_INCR(bs->count_transfer_irq);
+
/* fill in registers and fifos before enabling interrupts */
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]);
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]);
@@ -265,6 +318,9 @@ static int bcm2835aux_spi_transfer_one_poll(struct spi_master *master,
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
unsigned long timeout;

+ /* update statistics */
+ BCM2835_AUX_INCR(bs->count_transfer_polling);
+
/* configure spi */
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]);
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]);
@@ -285,6 +341,7 @@ static int bcm2835aux_spi_transfer_one_poll(struct spi_master *master,
jiffies - timeout,
bs->tx_len, bs->rx_len);
/* forward to interrupt handler */
+ BCM2835_AUX_INCR(bs->count_transfer_irq_after_poll);
return __bcm2835aux_spi_transfer_one_irq(master,
spi, tfr);
}
@@ -531,6 +588,8 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)
goto out_clk_disable;
}

+ bcm2835aux_debugfs_create(bs, dev_name(&pdev->dev));
+
return 0;

out_clk_disable:
@@ -545,6 +604,8 @@ static int bcm2835aux_spi_remove(struct platform_device *pdev)
struct spi_master *master = platform_get_drvdata(pdev);
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);

+ bcm2835aux_debugfs_remove(bs);
+
bcm2835aux_spi_reset_hw(bs);

/* disable the HW block by releasing the clock */