diff options
Diffstat (limited to 'drivers/spi/spi-bcm2835.c')
| -rw-r--r-- | drivers/spi/spi-bcm2835.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 3230d37fa89a..eb67da697ef5 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -22,6 +22,7 @@ #include <linux/clk.h> #include <linux/completion.h> +#include <linux/debugfs.h> #include <linux/delay.h> #include <linux/dma-mapping.h> #include <linux/dmaengine.h> @@ -101,6 +102,15 @@ MODULE_PARM_DESC(polling_limit_us, * length is not a multiple of 4 (to overcome hardware limitation) * @tx_spillover: whether @tx_prologue spills over to second TX sglist entry * @dma_pending: whether a DMA transfer is in progress + * @debugfs_dir: the debugfs directory - neede to remove debugfs when + * unloading the module + * @count_transfer_polling: count of how often polling mode is used + * @count_transfer_irq: count of how often interrupt mode is used + * @count_transfer_irq_after_polling: count of how often we fall back to + * interrupt mode after starting in polling mode. + * These are counted as well in @count_transfer_polling and + * @count_transfer_irq + * @count_transfer_dma: count how often dma mode is used */ struct bcm2835_spi { void __iomem *regs; @@ -115,8 +125,55 @@ struct bcm2835_spi { int rx_prologue; unsigned int tx_spillover; unsigned int dma_pending; + + struct dentry *debugfs_dir; + u64 count_transfer_polling; + u64 count_transfer_irq; + u64 count_transfer_irq_after_polling; + u64 count_transfer_dma; }; +#if defined(CONFIG_DEBUG_FS) +static void bcm2835_debugfs_create(struct bcm2835_spi *bs, + const char *dname) +{ + char name[64]; + struct dentry *dir; + + /* get full name */ + snprintf(name, sizeof(name), "spi-bcm2835-%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_polling", 0444, dir, + &bs->count_transfer_irq_after_polling); + debugfs_create_u64("count_transfer_dma", 0444, dir, + &bs->count_transfer_dma); +} + +static void bcm2835_debugfs_remove(struct bcm2835_spi *bs) +{ + debugfs_remove_recursive(bs->debugfs_dir); + bs->debugfs_dir = NULL; +} +#else +static void bcm2835_debugfs_create(struct bcm2835_spi *bs, + const char *dname) +{ +} + +static void bcm2835_debugfs_remove(struct bcm2835_spi *bs) +{ +} +#endif /* CONFIG_DEBUG_FS */ + static inline u32 bcm2835_rd(struct bcm2835_spi *bs, unsigned reg) { return readl(bs->regs + reg); @@ -320,6 +377,9 @@ static int bcm2835_spi_transfer_one_irq(struct spi_master *master, { struct bcm2835_spi *bs = spi_master_get_devdata(master); + /* update usage statistics */ + bs->count_transfer_irq++; + /* * Enable HW block, but with interrupts still disabled. * Otherwise the empty TX FIFO would immediately trigger an interrupt. @@ -564,6 +624,9 @@ static int bcm2835_spi_transfer_one_dma(struct spi_master *master, struct bcm2835_spi *bs = spi_master_get_devdata(master); int ret; + /* update usage statistics */ + bs->count_transfer_dma++; + /* * Transfer first few bytes without DMA if length of first TX or RX * sglist entry is not a multiple of 4 bytes (hardware limitation). @@ -706,6 +769,9 @@ static int bcm2835_spi_transfer_one_poll(struct spi_master *master, struct bcm2835_spi *bs = spi_master_get_devdata(master); unsigned long timeout; + /* update usage statistics */ + bs->count_transfer_polling++; + /* enable HW block without interrupts */ bcm2835_wr(bs, BCM2835_SPI_CS, cs | BCM2835_SPI_CS_TA); @@ -735,6 +801,10 @@ static int bcm2835_spi_transfer_one_poll(struct spi_master *master, jiffies - timeout, bs->tx_len, bs->rx_len); /* fall back to interrupt mode */ + + /* update usage statistics */ + bs->count_transfer_irq_after_polling++; + return bcm2835_spi_transfer_one_irq(master, spi, tfr, cs, false); } @@ -982,6 +1052,8 @@ static int bcm2835_spi_probe(struct platform_device *pdev) goto out_clk_disable; } + bcm2835_debugfs_create(bs, dev_name(&pdev->dev)); + return 0; out_clk_disable: @@ -996,6 +1068,8 @@ static int bcm2835_spi_remove(struct platform_device *pdev) struct spi_master *master = platform_get_drvdata(pdev); struct bcm2835_spi *bs = spi_master_get_devdata(master); + bcm2835_debugfs_remove(bs); + /* Clear FIFOs, and disable the HW block */ bcm2835_wr(bs, BCM2835_SPI_CS, BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX); |