From: Suzuki K Poulose <suzuki.poulose@arm.com> To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, mathieu.poirier@linaro.org, coresight@lists.linaro.org, suzuki.poulose@arm.com, robert.walker@arm.com, al.grant@arm.com Subject: [PATCH v2 09/14] coresight: Add support for CLAIM tag protocol Date: Thu, 6 Sep 2018 10:08:30 +0100 [thread overview] Message-ID: <1536224915-31766-10-git-send-email-suzuki.poulose@arm.com> (raw) In-Reply-To: <1536224915-31766-1-git-send-email-suzuki.poulose@arm.com> Coresight architecture defines CLAIM tags for a device to negotiate control of the components (external agent vs self-hosted). Each device has a pair of registers (CLAIMSET & CLAIMCLR) for managing the CLAIM tags. However, the protocol for the CLAIM tags is IMPLEMENTATION DEFINED. PSCI has recommendations for the use of the CLAIM tags to negotiate controls for external agent vs self-hosted use. This patch implements the recommended protocol by PSCI. The claim/disclaim operations are performed from the device specific drivers. The disadvantage is that the calls are sprinkled in each driver, but this makes the operation much simpler. Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- drivers/hwtracing/coresight/coresight-priv.h | 7 +++ drivers/hwtracing/coresight/coresight.c | 86 ++++++++++++++++++++++++++++ include/linux/coresight.h | 20 +++++++ 3 files changed, 113 insertions(+) diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index c11da55..579f349 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -25,6 +25,13 @@ #define CORESIGHT_DEVID 0xfc8 #define CORESIGHT_DEVTYPE 0xfcc + +/* + * Coresight device CLAIM protocol. + * See PSCI - ARM DEN 0022D, Section: 6.8.1 Debug and Trace save and restore. + */ +#define CORESIGHT_CLAIM_SELF_HOSTED BIT(1) + #define TIMEOUT_US 100 #define BMVAL(val, lsb, msb) ((val & GENMASK(msb, lsb)) >> lsb) diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index f4f5075..2b0df1a 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -128,6 +128,92 @@ static int coresight_find_link_outport(struct coresight_device *csdev, return -ENODEV; } +static inline u32 coresight_read_claim_tags(void __iomem *base) +{ + return readl_relaxed(base + CORESIGHT_CLAIMCLR); +} + +static inline bool coresight_is_claimed_self_hosted(void __iomem *base) +{ + return coresight_read_claim_tags(base) == CORESIGHT_CLAIM_SELF_HOSTED; +} + +static inline bool coresight_is_claimed_any(void __iomem *base) +{ + return coresight_read_claim_tags(base) != 0; +} + +static inline void coresight_set_claim_tags(void __iomem *base) +{ + writel_relaxed(CORESIGHT_CLAIM_SELF_HOSTED, base + CORESIGHT_CLAIMSET); + isb(); +} + +static inline void coresight_clear_claim_tags(void __iomem *base) +{ + writel_relaxed(CORESIGHT_CLAIM_SELF_HOSTED, base + CORESIGHT_CLAIMCLR); + isb(); +} + +/* + * coresight_claim_device_unlocked : Claim the device for self-hosted usage + * to prevent an external tool from touching this device. As per PSCI + * standards, section "Preserving the execution context" => "Debug and Trace + * save and Restore", DBGCLAIM[1] is reserved for Self-hosted debug/trace and + * DBGCLAIM[0] is reserved for external tools. + * + * Called with CS_UNLOCKed for the component. + * Returns : 0 on success + */ +int coresight_claim_device_unlocked(void __iomem *base) +{ + if (coresight_is_claimed_any(base)) + return -EBUSY; + + coresight_set_claim_tags(base); + if (coresight_is_claimed_self_hosted(base)) + return 0; + /* There was a race setting the tags, clean up and fail */ + coresight_clear_claim_tags(base); + return -EBUSY; +} + +int coresight_claim_device(void __iomem *base) +{ + int rc; + + CS_UNLOCK(base); + rc = coresight_claim_device_unlocked(base); + CS_LOCK(base); + + return rc; +} + +/* + * coresight_disclaim_device_unlocked : Clear the claim tags for the device. + * Called with CS_UNLOCKed for the component. + */ +void coresight_disclaim_device_unlocked(void __iomem *base) +{ + + if (coresight_is_claimed_self_hosted(base)) + coresight_clear_claim_tags(base); + else + /* + * The external agent may have not honoured our claim + * and has manipulated it. Or something else has seriously + * gone wrong in our driver. + */ + WARN_ON_ONCE(1); +} + +void coresight_disclaim_device(void __iomem *base) +{ + CS_UNLOCK(base); + coresight_disclaim_device_unlocked(base); + CS_LOCK(base); +} + static int coresight_enable_sink(struct coresight_device *csdev, u32 mode, void *data) { diff --git a/include/linux/coresight.h b/include/linux/coresight.h index 5353582..46c67a7 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -257,6 +257,13 @@ extern int coresight_enable(struct coresight_device *csdev); extern void coresight_disable(struct coresight_device *csdev); extern int coresight_timeout(void __iomem *addr, u32 offset, int position, int value); + +extern int coresight_claim_device(void __iomem *base); +extern int coresight_claim_device_unlocked(void __iomem *base); + +extern void coresight_disclaim_device(void __iomem *base); +extern void coresight_disclaim_device_unlocked(void __iomem *base); + #else static inline struct coresight_device * coresight_register(struct coresight_desc *desc) { return NULL; } @@ -266,6 +273,19 @@ coresight_enable(struct coresight_device *csdev) { return -ENOSYS; } static inline void coresight_disable(struct coresight_device *csdev) {} static inline int coresight_timeout(void __iomem *addr, u32 offset, int position, int value) { return 1; } +static inline int coresight_claim_device_unlocked(void __iomem *base) +{ + return -EINVAL; +} + +static inline int coresight_claim_device(void __iomem *base) +{ + return -EINVAL; +} + +static inline void coresight_disclaim_device(void __iomem *base) {} +static inline void coresight_disclaim_device_unlocked(void __iomem *base) {} + #endif #ifdef CONFIG_OF -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: suzuki.poulose@arm.com (Suzuki K Poulose) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 09/14] coresight: Add support for CLAIM tag protocol Date: Thu, 6 Sep 2018 10:08:30 +0100 [thread overview] Message-ID: <1536224915-31766-10-git-send-email-suzuki.poulose@arm.com> (raw) In-Reply-To: <1536224915-31766-1-git-send-email-suzuki.poulose@arm.com> Coresight architecture defines CLAIM tags for a device to negotiate control of the components (external agent vs self-hosted). Each device has a pair of registers (CLAIMSET & CLAIMCLR) for managing the CLAIM tags. However, the protocol for the CLAIM tags is IMPLEMENTATION DEFINED. PSCI has recommendations for the use of the CLAIM tags to negotiate controls for external agent vs self-hosted use. This patch implements the recommended protocol by PSCI. The claim/disclaim operations are performed from the device specific drivers. The disadvantage is that the calls are sprinkled in each driver, but this makes the operation much simpler. Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- drivers/hwtracing/coresight/coresight-priv.h | 7 +++ drivers/hwtracing/coresight/coresight.c | 86 ++++++++++++++++++++++++++++ include/linux/coresight.h | 20 +++++++ 3 files changed, 113 insertions(+) diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index c11da55..579f349 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -25,6 +25,13 @@ #define CORESIGHT_DEVID 0xfc8 #define CORESIGHT_DEVTYPE 0xfcc + +/* + * Coresight device CLAIM protocol. + * See PSCI - ARM DEN 0022D, Section: 6.8.1 Debug and Trace save and restore. + */ +#define CORESIGHT_CLAIM_SELF_HOSTED BIT(1) + #define TIMEOUT_US 100 #define BMVAL(val, lsb, msb) ((val & GENMASK(msb, lsb)) >> lsb) diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index f4f5075..2b0df1a 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -128,6 +128,92 @@ static int coresight_find_link_outport(struct coresight_device *csdev, return -ENODEV; } +static inline u32 coresight_read_claim_tags(void __iomem *base) +{ + return readl_relaxed(base + CORESIGHT_CLAIMCLR); +} + +static inline bool coresight_is_claimed_self_hosted(void __iomem *base) +{ + return coresight_read_claim_tags(base) == CORESIGHT_CLAIM_SELF_HOSTED; +} + +static inline bool coresight_is_claimed_any(void __iomem *base) +{ + return coresight_read_claim_tags(base) != 0; +} + +static inline void coresight_set_claim_tags(void __iomem *base) +{ + writel_relaxed(CORESIGHT_CLAIM_SELF_HOSTED, base + CORESIGHT_CLAIMSET); + isb(); +} + +static inline void coresight_clear_claim_tags(void __iomem *base) +{ + writel_relaxed(CORESIGHT_CLAIM_SELF_HOSTED, base + CORESIGHT_CLAIMCLR); + isb(); +} + +/* + * coresight_claim_device_unlocked : Claim the device for self-hosted usage + * to prevent an external tool from touching this device. As per PSCI + * standards, section "Preserving the execution context" => "Debug and Trace + * save and Restore", DBGCLAIM[1] is reserved for Self-hosted debug/trace and + * DBGCLAIM[0] is reserved for external tools. + * + * Called with CS_UNLOCKed for the component. + * Returns : 0 on success + */ +int coresight_claim_device_unlocked(void __iomem *base) +{ + if (coresight_is_claimed_any(base)) + return -EBUSY; + + coresight_set_claim_tags(base); + if (coresight_is_claimed_self_hosted(base)) + return 0; + /* There was a race setting the tags, clean up and fail */ + coresight_clear_claim_tags(base); + return -EBUSY; +} + +int coresight_claim_device(void __iomem *base) +{ + int rc; + + CS_UNLOCK(base); + rc = coresight_claim_device_unlocked(base); + CS_LOCK(base); + + return rc; +} + +/* + * coresight_disclaim_device_unlocked : Clear the claim tags for the device. + * Called with CS_UNLOCKed for the component. + */ +void coresight_disclaim_device_unlocked(void __iomem *base) +{ + + if (coresight_is_claimed_self_hosted(base)) + coresight_clear_claim_tags(base); + else + /* + * The external agent may have not honoured our claim + * and has manipulated it. Or something else has seriously + * gone wrong in our driver. + */ + WARN_ON_ONCE(1); +} + +void coresight_disclaim_device(void __iomem *base) +{ + CS_UNLOCK(base); + coresight_disclaim_device_unlocked(base); + CS_LOCK(base); +} + static int coresight_enable_sink(struct coresight_device *csdev, u32 mode, void *data) { diff --git a/include/linux/coresight.h b/include/linux/coresight.h index 5353582..46c67a7 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -257,6 +257,13 @@ extern int coresight_enable(struct coresight_device *csdev); extern void coresight_disable(struct coresight_device *csdev); extern int coresight_timeout(void __iomem *addr, u32 offset, int position, int value); + +extern int coresight_claim_device(void __iomem *base); +extern int coresight_claim_device_unlocked(void __iomem *base); + +extern void coresight_disclaim_device(void __iomem *base); +extern void coresight_disclaim_device_unlocked(void __iomem *base); + #else static inline struct coresight_device * coresight_register(struct coresight_desc *desc) { return NULL; } @@ -266,6 +273,19 @@ coresight_enable(struct coresight_device *csdev) { return -ENOSYS; } static inline void coresight_disable(struct coresight_device *csdev) {} static inline int coresight_timeout(void __iomem *addr, u32 offset, int position, int value) { return 1; } +static inline int coresight_claim_device_unlocked(void __iomem *base) +{ + return -EINVAL; +} + +static inline int coresight_claim_device(void __iomem *base) +{ + return -EINVAL; +} + +static inline void coresight_disclaim_device(void __iomem *base) {} +static inline void coresight_disclaim_device_unlocked(void __iomem *base) {} + #endif #ifdef CONFIG_OF -- 2.7.4
next prev parent reply other threads:[~2018-09-06 9:09 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-09-06 9:08 [PATCH v2 00/14] coresight: Implement device claim protocol Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 01/14] coresight: Handle failures in enabling a trace path Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 02/14] coresight: tmc-etr: Refactor for handling errors Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 03/14] coresight: tmc-etr: Handle errors enabling CATU Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 04/14] coresight: tmc-etb/etf: Prepare to handle errors enabling Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 05/14] coresight: etm4x: Add support for handling errors Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 06/14] coresight: etm3: " Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 07/14] coresight: etb10: Handle errors enabling the device Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 08/14] coresight: dynamic-replicator: Handle multiple connections Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose [this message] 2018-09-06 9:08 ` [PATCH v2 09/14] coresight: Add support for CLAIM tag protocol Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 10/14] coresight: etmx: Claim devices before use Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 11/14] coresight: funnel: " Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 12/14] coresight: catu: Claim device " Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 13/14] coresight: dynamic-replicator: Claim device for use Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-06 9:08 ` [PATCH v2 14/14] coreisght: tmc: Claim device before use Suzuki K Poulose 2018-09-06 9:08 ` Suzuki K Poulose 2018-09-12 19:42 ` [PATCH v2 00/14] coresight: Implement device claim protocol Mathieu Poirier 2018-09-12 19:42 ` Mathieu Poirier
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1536224915-31766-10-git-send-email-suzuki.poulose@arm.com \ --to=suzuki.poulose@arm.com \ --cc=al.grant@arm.com \ --cc=coresight@lists.linaro.org \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=mathieu.poirier@linaro.org \ --cc=robert.walker@arm.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.