From: kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org To: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Eric Anholt <eric-WhKQ6XTQaPysTnJN9+BGXg@public.gmane.org>, Stefan Wahren <stefan.wahren-eS4NqCHxEME@public.gmane.org>, Hubert Denkmair <h.denkmair-4pT7WzY1KUiELgA04lAiVw@public.gmane.org>, linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Subject: [PATCH V2 9/9] spi: bcm2835aux: make the polling duration limits configurable Date: Sun, 24 Mar 2019 17:50:02 +0000 [thread overview] Message-ID: <20190324175002.28969-10-kernel@martin.sperl.org> (raw) In-Reply-To: <20190324175002.28969-1-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org> From: Martin Sperl <kernel@martin.sperl.org> Under some circumstances the default 30 us polling limit is not optimal and may lead to long delays because we are waiting on an interrupt. with this patch we have the possibility to influence this policy. So make this limit (in us) configurable via a module parameters (but also modifyable via /sys/modules/...) Signed-off-by: Martin Sperl <kernel@martin.sperl.org> --- Changelog: V1 -> V2: remove the dependency on a different patchset focused on making cs_change delay configurable --- drivers/spi/spi-bcm2835aux.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index d2b58060b333..df065108122b 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -37,6 +37,12 @@ #include <linux/spi/spi.h> #include <linux/spinlock.h> +/* define polling limits */ +unsigned int polling_limit_us = 30; +module_param(polling_limit_us, uint, 0664); +MODULE_PARM_DESC(polling_limit_us, + "time in us to run a transfer in polling mode\n"); + /* * spi register defines * @@ -89,10 +95,6 @@ #define BCM2835_AUX_SPI_STAT_BUSY 0x00000040 #define BCM2835_AUX_SPI_STAT_BITCOUNT 0x0000003F -/* timeout values */ -#define BCM2835_AUX_SPI_POLLING_LIMIT_US 30 -#define BCM2835_AUX_SPI_POLLING_JIFFIES 2 - struct bcm2835aux_spi { void __iomem *regs; struct clk *clk; @@ -325,8 +327,8 @@ static int bcm2835aux_spi_transfer_one_poll(struct spi_master *master, bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]); bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]); - /* set the timeout */ - timeout = jiffies + BCM2835_AUX_SPI_POLLING_JIFFIES; + /* set the timeout to at least 2 jiffies */ + timeout = jiffies + 2 + HZ * polling_limit_us / 1000000; /* loop until finished the transfer */ while (bs->rx_len) { @@ -356,8 +358,8 @@ static int bcm2835aux_spi_transfer_one(struct spi_master *master, struct spi_transfer *tfr) { struct bcm2835aux_spi *bs = spi_master_get_devdata(master); - unsigned long spi_hz, clk_hz, speed; - unsigned long spi_used_hz; + unsigned long spi_hz, clk_hz, speed, spi_used_hz; + unsigned long hz_per_byte, byte_limit; /* calculate the registers to handle * @@ -401,14 +403,15 @@ static int bcm2835aux_spi_transfer_one(struct spi_master *master, * of Hz per byte per polling limit. E.g., we can transfer 1 byte in * 30 µs per 300,000 Hz of bus clock. */ -#define HZ_PER_BYTE ((9 * 1000000) / BCM2835_AUX_SPI_POLLING_LIMIT_US) + hz_per_byte = polling_limit_us ? (9 * 1000000) / polling_limit_us : 0; + byte_limit = hz_per_byte ? spi_used_hz / hz_per_byte : 1; + /* run in polling mode for short transfers */ - if (tfr->len < spi_used_hz / HZ_PER_BYTE) + if (tfr->len < byte_limit) return bcm2835aux_spi_transfer_one_poll(master, spi, tfr); /* run in interrupt mode for all others */ return bcm2835aux_spi_transfer_one_irq(master, spi, tfr); -#undef HZ_PER_BYTE } static int bcm2835aux_spi_prepare_message(struct spi_master *master, -- 2.11.0 _______________________________________________ linux-rpi-kernel mailing list linux-rpi-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rpi-kernel
WARNING: multiple messages have this Message-ID (diff)
From: kernel@martin.sperl.org To: Mark Brown <broonie@kernel.org>, Eric Anholt <eric@anholt.net>, Stefan Wahren <stefan.wahren@i2se.com>, Hubert Denkmair <h.denkmair@intence.de>, linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Cc: Martin Sperl <kernel@martin.sperl.org> Subject: [PATCH V2 9/9] spi: bcm2835aux: make the polling duration limits configurable Date: Sun, 24 Mar 2019 17:50:02 +0000 [thread overview] Message-ID: <20190324175002.28969-10-kernel@martin.sperl.org> (raw) In-Reply-To: <20190324175002.28969-1-kernel@martin.sperl.org> From: Martin Sperl <kernel@martin.sperl.org> Under some circumstances the default 30 us polling limit is not optimal and may lead to long delays because we are waiting on an interrupt. with this patch we have the possibility to influence this policy. So make this limit (in us) configurable via a module parameters (but also modifyable via /sys/modules/...) Signed-off-by: Martin Sperl <kernel@martin.sperl.org> --- Changelog: V1 -> V2: remove the dependency on a different patchset focused on making cs_change delay configurable --- drivers/spi/spi-bcm2835aux.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index d2b58060b333..df065108122b 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -37,6 +37,12 @@ #include <linux/spi/spi.h> #include <linux/spinlock.h> +/* define polling limits */ +unsigned int polling_limit_us = 30; +module_param(polling_limit_us, uint, 0664); +MODULE_PARM_DESC(polling_limit_us, + "time in us to run a transfer in polling mode\n"); + /* * spi register defines * @@ -89,10 +95,6 @@ #define BCM2835_AUX_SPI_STAT_BUSY 0x00000040 #define BCM2835_AUX_SPI_STAT_BITCOUNT 0x0000003F -/* timeout values */ -#define BCM2835_AUX_SPI_POLLING_LIMIT_US 30 -#define BCM2835_AUX_SPI_POLLING_JIFFIES 2 - struct bcm2835aux_spi { void __iomem *regs; struct clk *clk; @@ -325,8 +327,8 @@ static int bcm2835aux_spi_transfer_one_poll(struct spi_master *master, bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]); bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]); - /* set the timeout */ - timeout = jiffies + BCM2835_AUX_SPI_POLLING_JIFFIES; + /* set the timeout to at least 2 jiffies */ + timeout = jiffies + 2 + HZ * polling_limit_us / 1000000; /* loop until finished the transfer */ while (bs->rx_len) { @@ -356,8 +358,8 @@ static int bcm2835aux_spi_transfer_one(struct spi_master *master, struct spi_transfer *tfr) { struct bcm2835aux_spi *bs = spi_master_get_devdata(master); - unsigned long spi_hz, clk_hz, speed; - unsigned long spi_used_hz; + unsigned long spi_hz, clk_hz, speed, spi_used_hz; + unsigned long hz_per_byte, byte_limit; /* calculate the registers to handle * @@ -401,14 +403,15 @@ static int bcm2835aux_spi_transfer_one(struct spi_master *master, * of Hz per byte per polling limit. E.g., we can transfer 1 byte in * 30 µs per 300,000 Hz of bus clock. */ -#define HZ_PER_BYTE ((9 * 1000000) / BCM2835_AUX_SPI_POLLING_LIMIT_US) + hz_per_byte = polling_limit_us ? (9 * 1000000) / polling_limit_us : 0; + byte_limit = hz_per_byte ? spi_used_hz / hz_per_byte : 1; + /* run in polling mode for short transfers */ - if (tfr->len < spi_used_hz / HZ_PER_BYTE) + if (tfr->len < byte_limit) return bcm2835aux_spi_transfer_one_poll(master, spi, tfr); /* run in interrupt mode for all others */ return bcm2835aux_spi_transfer_one_irq(master, spi, tfr); -#undef HZ_PER_BYTE } static int bcm2835aux_spi_prepare_message(struct spi_master *master, -- 2.11.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-03-24 17:50 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-03-24 17:49 [PATCH V2 0/9] spi: bcm2835aux: bug fixes and improvements kernel 2019-03-24 17:49 ` kernel 2019-03-24 17:49 ` [PATCH V2 3/9] spi: bcm2835aux: use BCM2835_AUX_SPI_STAT_RX_LVL kernel 2019-03-24 17:49 ` kernel 2019-03-25 9:52 ` Stefan Wahren 2019-03-25 9:52 ` Stefan Wahren 2019-03-24 17:49 ` [PATCH V2 6/9] spi: bcm2835aux: warn in dmesg that native cs is not really supported kernel 2019-03-24 17:49 ` kernel 2019-03-25 10:28 ` Stefan Wahren 2019-03-25 10:28 ` Stefan Wahren [not found] ` <20190324175002.28969-1-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org> 2019-03-24 17:49 ` [PATCH V2 1/9] spi: bcm2835aux: unifying code between polling and interrupt driven code kernel-TqfNSX0MhmxHKSADF0wUEw 2019-03-24 17:49 ` kernel 2019-03-24 17:49 ` [PATCH V2 2/9] spi: bcm2835aux: remove dangerous uncontrolled read of fifo kernel-TqfNSX0MhmxHKSADF0wUEw 2019-03-24 17:49 ` kernel 2019-03-24 17:49 ` [PATCH V2 4/9] spi: bcm2835aux: remove dead code kernel-TqfNSX0MhmxHKSADF0wUEw 2019-03-24 17:49 ` kernel 2019-03-24 17:49 ` [PATCH V2 5/9] spi: bcm2835aux: fix driver to not allow 65535 (=-1) cs-gpios kernel-TqfNSX0MhmxHKSADF0wUEw 2019-03-24 17:49 ` kernel 2019-03-24 17:50 ` [PATCH V2 7/9] spi: bcm2835aux: setup gpio-cs to output and correct level during setup kernel-TqfNSX0MhmxHKSADF0wUEw 2019-03-24 17:50 ` kernel 2019-03-24 17:50 ` [PATCH V2 8/9] spi: bcm2835aux: add driver stats to debugfs kernel-TqfNSX0MhmxHKSADF0wUEw 2019-03-24 17:50 ` kernel 2019-03-25 9:28 ` Stefan Wahren 2019-03-25 9:28 ` Stefan Wahren 2019-03-25 9:52 ` kernel 2019-03-25 10:06 ` Stefan Wahren 2019-03-25 10:11 ` kernel 2019-03-25 10:45 ` Stefan Wahren 2019-03-24 17:50 ` kernel-TqfNSX0MhmxHKSADF0wUEw [this message] 2019-03-24 17:50 ` [PATCH V2 9/9] spi: bcm2835aux: make the polling duration limits configurable kernel 2019-03-25 9:44 ` Stefan Wahren 2019-03-25 9:44 ` Stefan Wahren 2019-03-25 9:49 ` kernel 2019-03-25 9:49 ` kernel 2019-03-25 9:59 ` Stefan Wahren 2019-03-25 9:59 ` Stefan Wahren
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