CoreSight ETM4x devices could be accessed either via MMIO (handled via
amba_driver) or CPU system instructions (handled via platform driver). But
this has the following issues :
- Each new CPU comes up with its own PID and thus we need to keep on
adding the "known" PIDs to get it working with AMBA driver. While
the ETM4 architecture (and CoreSight architecture) defines way to
identify a device as ETM4. Thus older kernels won't be able to
"discover" a newer CPU, unless we add the PIDs.
- With ACPI, the ETM4x devices have the same HID to identify the device
irrespective of the mode of access. This creates a problem where two
different drivers (both AMBA based driver and platform driver) would
hook into the "HID" and could conflict. e.g., if AMBA driver gets
hold of a non-MMIO device, the probe fails. If we have single driver
hooked into the given "HID", we could handle them seamlessly,
irrespective of the mode of access.
- CoreSight is heavily dependent on the runtime power management. With
ACPI, amba_driver doesn't get us anywhere with handling the power
and thus one need to always turn the power ON to use them. Moving to
platform driver gives us the power management for free.
Due to all of the above, we are moving ACPI MMIO based etm4x devices to be
supported via tha platform driver. The series makes the existing platform
driver generic to handle both type of the access modes. Although existing
AMBA driver would still continue to support DT based etm4x MMIO devices.
Although some problems still remain, such as manually adding PIDs for all
new AMBA DT based devices.
The series applies on 6.4-rc3.
Changes in V4:
- Changed in-code comment in etm4_check_arch_features()
- Re-ordered pm_runtime_disable() in etm4_remove_platform_dev()
- Renamed back etm4_match as etm4_sysreg_match
- Moved back [PATCH 6/6] as [PATCH 5/6]
Changes in V3:
https://lore.kernel.org/all/[email protected]/
- Returned from etm4_check_arch_features() for non iomem devices
- Renamed ETM_DEVTYPE_ETMv4x_ARCH as CS_DEVTYPE_PE_TRACE
- Renamed is_etm4x_devtype() as is_devtype_cpu_trace()
- Added a patch to ignore the absence of graph connections
Changes in V2:
https://lore.kernel.org/all/[email protected]/
- Enables ACPI etm4x device support in the existing platform driver
- Dropped last two patches from the series
- Dropped redundant 'devarch' checking from is_etm4x_device()
- Renamed updated is_etm4x_device() as is_etm4x_devtype()
- Fixed arguments in fallback stub for etm4_check_arch_features()
- Tagged etm4_dev_pm_ops with etm4_platform_driver
- Updated the comment for coresight_get_enable_apb_pclk() helper
- Updated the comment for new 'pclk' element in struct etm4_drvdata
- Dropped the clock when devm_ioremap_resource() fails
- Convert IS_ERR() into a direct pointer check in etm4_remove_platform_dev()
- Dropped "arm,coresight-etm4x" compatible property from etm4_match[]
Changes in V1:
https://lore.kernel.org/all/[email protected]/
Cc: Ganapatrao Kulkarni <[email protected]>
Cc: Steve Clevenger <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Frank Rowand <[email protected]>
Cc: Russell King (Oracle) <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Sudeep Holla <[email protected]>
Cc: Lorenzo Pieralisi <[email protected]>
Cc: Mathieu Poirier <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Anshuman Khandual (4):
coresight: etm4x: Allocate and device assign 'struct etmv4_drvdata' earlier
coresight: etm4x: Drop iomem 'base' argument from etm4_probe()
coresight: etm4x: Drop pid argument from etm4_probe()
coresight: etm4x: Change etm4_platform_driver driver for MMIO devices
Suzuki K Poulose (2):
coresight: platform: acpi: Ignore the absence of graph
coresight: etm4x: Add ACPI support in platform driver
drivers/acpi/acpi_amba.c | 1 -
.../coresight/coresight-etm4x-core.c | 117 ++++++++++++++----
drivers/hwtracing/coresight/coresight-etm4x.h | 4 +
.../hwtracing/coresight/coresight-platform.c | 6 +-
include/linux/coresight.h | 59 +++++++++
5 files changed, 163 insertions(+), 24 deletions(-)
--
2.25.1
Allocate and device assign 'struct etmv4_drvdata' earlier during the driver
probe, ensuring that it can be retrieved in power management based runtime
callbacks if required. This will also help in dropping iomem base address
argument from the function etm4_probe() later.
Cc: Mathieu Poirier <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
---
.../coresight/coresight-etm4x-core.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 4c15fae534f3..7e96293c638f 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -2046,17 +2046,14 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
{
- struct etmv4_drvdata *drvdata;
+ struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
struct csdev_access access = { 0 };
struct etm4_init_arg init_arg = { 0 };
struct etm4_init_arg *delayed;
- drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
- if (!drvdata)
+ if (WARN_ON(!drvdata))
return -ENOMEM;
- dev_set_drvdata(dev, drvdata);
-
if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE)
pm_save_enable = coresight_loses_context_with_cpu(dev) ?
PARAM_PM_SAVE_SELF_HOSTED : PARAM_PM_SAVE_NEVER;
@@ -2108,6 +2105,7 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
{
+ struct etmv4_drvdata *drvdata;
void __iomem *base;
struct device *dev = &adev->dev;
struct resource *res = &adev->res;
@@ -2118,6 +2116,11 @@ static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
if (IS_ERR(base))
return PTR_ERR(base);
+ drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
+ if (!drvdata)
+ return -ENOMEM;
+
+ dev_set_drvdata(dev, drvdata);
ret = etm4_probe(dev, base, id->id);
if (!ret)
pm_runtime_put(&adev->dev);
@@ -2127,8 +2130,14 @@ static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
static int etm4_probe_platform_dev(struct platform_device *pdev)
{
+ struct etmv4_drvdata *drvdata;
int ret;
+ drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
+ if (!drvdata)
+ return -ENOMEM;
+
+ dev_set_drvdata(&pdev->dev, drvdata);
pm_runtime_get_noresume(&pdev->dev);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
--
2.25.1
'struct etm4_drvdata' itself can carry the base address before etm4_probe()
gets called. Just drop that redundant argument from etm4_probe().
Cc: Mathieu Poirier <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Reviewed-by: James Clark <[email protected]>
Signed-off-by: Anshuman Khandual <[email protected]>
---
drivers/hwtracing/coresight/coresight-etm4x-core.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 7e96293c638f..748d2ef53cb0 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -2044,7 +2044,7 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
return 0;
}
-static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
+static int etm4_probe(struct device *dev, u32 etm_pid)
{
struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
struct csdev_access access = { 0 };
@@ -2065,8 +2065,6 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
return -ENOMEM;
}
- drvdata->base = base;
-
spin_lock_init(&drvdata->spinlock);
drvdata->cpu = coresight_get_cpu(dev);
@@ -2120,8 +2118,9 @@ static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
if (!drvdata)
return -ENOMEM;
+ drvdata->base = base;
dev_set_drvdata(dev, drvdata);
- ret = etm4_probe(dev, base, id->id);
+ ret = etm4_probe(dev, id->id);
if (!ret)
pm_runtime_put(&adev->dev);
@@ -2137,6 +2136,7 @@ static int etm4_probe_platform_dev(struct platform_device *pdev)
if (!drvdata)
return -ENOMEM;
+ drvdata->base = NULL;
dev_set_drvdata(&pdev->dev, drvdata);
pm_runtime_get_noresume(&pdev->dev);
pm_runtime_set_active(&pdev->dev);
@@ -2147,7 +2147,7 @@ static int etm4_probe_platform_dev(struct platform_device *pdev)
* HW by reading appropriate registers on the HW
* and thus we could skip the PID.
*/
- ret = etm4_probe(&pdev->dev, NULL, 0);
+ ret = etm4_probe(&pdev->dev, 0);
pm_runtime_put(&pdev->dev);
return ret;
--
2.25.1
Coresight device pid can be retrieved from its iomem base address, which is
stored in 'struct etm4x_drvdata'. This drops pid argument from etm4_probe()
and 'struct etm4_init_arg'. Instead etm4_check_arch_features() derives the
coresight device pid with a new helper coresight_get_pid(), right before it
is consumed in etm4_hisi_match_pid().
Cc: Mathieu Poirier <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
---
.../coresight/coresight-etm4x-core.c | 29 ++++++++++---------
include/linux/coresight.h | 12 ++++++++
2 files changed, 27 insertions(+), 14 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 748d2ef53cb0..57a7181017bd 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -66,7 +66,6 @@ static u64 etm4_get_access_type(struct etmv4_config *config);
static enum cpuhp_state hp_online;
struct etm4_init_arg {
- unsigned int pid;
struct device *dev;
struct csdev_access *csa;
};
@@ -370,9 +369,17 @@ static void etm4_disable_arch_specific(struct etmv4_drvdata *drvdata)
}
static void etm4_check_arch_features(struct etmv4_drvdata *drvdata,
- unsigned int id)
+ struct csdev_access *csa)
{
- if (etm4_hisi_match_pid(id))
+ /*
+ * TRCPIDR* registers are not required for ETMs with system
+ * instructions. They must be identified by the MIDR+REVIDRs.
+ * Skip the TRCPID checks for now.
+ */
+ if (!csa->io_mem)
+ return;
+
+ if (etm4_hisi_match_pid(coresight_get_pid(csa)))
set_bit(ETM4_IMPDEF_HISI_CORE_COMMIT, drvdata->arch_features);
}
#else
@@ -385,7 +392,7 @@ static void etm4_disable_arch_specific(struct etmv4_drvdata *drvdata)
}
static void etm4_check_arch_features(struct etmv4_drvdata *drvdata,
- unsigned int id)
+ struct csdev_access *csa)
{
}
#endif /* CONFIG_ETM4X_IMPDEF_FEATURE */
@@ -1161,7 +1168,7 @@ static void etm4_init_arch_data(void *info)
etm4_os_unlock_csa(drvdata, csa);
etm4_cs_unlock(drvdata, csa);
- etm4_check_arch_features(drvdata, init_arg->pid);
+ etm4_check_arch_features(drvdata, csa);
/* find all capabilities of the tracing unit */
etmidr0 = etm4x_relaxed_read32(csa, TRCIDR0);
@@ -2044,7 +2051,7 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
return 0;
}
-static int etm4_probe(struct device *dev, u32 etm_pid)
+static int etm4_probe(struct device *dev)
{
struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
struct csdev_access access = { 0 };
@@ -2073,7 +2080,6 @@ static int etm4_probe(struct device *dev, u32 etm_pid)
init_arg.dev = dev;
init_arg.csa = &access;
- init_arg.pid = etm_pid;
/*
* Serialize against CPUHP callbacks to avoid race condition
@@ -2120,7 +2126,7 @@ static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
drvdata->base = base;
dev_set_drvdata(dev, drvdata);
- ret = etm4_probe(dev, id->id);
+ ret = etm4_probe(dev);
if (!ret)
pm_runtime_put(&adev->dev);
@@ -2142,12 +2148,7 @@ static int etm4_probe_platform_dev(struct platform_device *pdev)
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
- /*
- * System register based devices could match the
- * HW by reading appropriate registers on the HW
- * and thus we could skip the PID.
- */
- ret = etm4_probe(&pdev->dev, 0);
+ ret = etm4_probe(&pdev->dev);
pm_runtime_put(&pdev->dev);
return ret;
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index f19a47b9bb5a..f85b041ea475 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -370,6 +370,18 @@ static inline u32 csdev_access_relaxed_read32(struct csdev_access *csa,
return csa->read(offset, true, false);
}
+#define CORESIGHT_PIDRn(i) (0xFE0 + ((i) * 4))
+
+static inline u32 coresight_get_pid(struct csdev_access *csa)
+{
+ u32 i, pid = 0;
+
+ for (i = 0; i < 4; i++)
+ pid |= csdev_access_relaxed_read32(csa, CORESIGHT_PIDRn(i)) << (i * 8);
+
+ return pid;
+}
+
static inline u64 csdev_access_relaxed_read_pair(struct csdev_access *csa,
u32 lo_offset, u32 hi_offset)
{
--
2.25.1
From: Suzuki K Poulose <[email protected]>
Drop ETM4X ACPI ID from the AMBA ACPI device list, and instead just move it
inside the new ACPI devices list detected and used via platform driver.
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Mathieu Poirier <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Sudeep Holla <[email protected]>
Cc: Lorenzo Pieralisi <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Reviewed-by: Sudeep Holla <[email protected]> (for ACPI specific changes)
Signed-off-by: Suzuki K Poulose <[email protected]>
Signed-off-by: Anshuman Khandual <[email protected]>
---
drivers/acpi/acpi_amba.c | 1 -
drivers/hwtracing/coresight/coresight-etm4x-core.c | 10 ++++++++++
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/acpi_amba.c b/drivers/acpi/acpi_amba.c
index f5b443ab01c2..099966cbac5a 100644
--- a/drivers/acpi/acpi_amba.c
+++ b/drivers/acpi/acpi_amba.c
@@ -22,7 +22,6 @@
static const struct acpi_device_id amba_id_list[] = {
{"ARMH0061", 0}, /* PL061 GPIO Device */
{"ARMH0330", 0}, /* ARM DMA Controller DMA-330 */
- {"ARMHC500", 0}, /* ARM CoreSight ETM4x */
{"ARMHC501", 0}, /* ARM CoreSight ETR */
{"ARMHC502", 0}, /* ARM CoreSight STM */
{"ARMHC503", 0}, /* ARM CoreSight Debug */
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index c9e2219ee6b6..5f2c0c52b026 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -3,6 +3,7 @@
* Copyright (c) 2014, The Linux Foundation. All rights reserved.
*/
+#include <linux/acpi.h>
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/moduleparam.h>
@@ -2344,12 +2345,21 @@ static const struct of_device_id etm4_sysreg_match[] = {
{}
};
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id etm4x_acpi_ids[] = {
+ {"ARMHC500", 0}, /* ARM CoreSight ETM4x */
+ {}
+};
+MODULE_DEVICE_TABLE(acpi, etm4x_acpi_ids);
+#endif
+
static struct platform_driver etm4_platform_driver = {
.probe = etm4_probe_platform_dev,
.remove = etm4_remove_platform_dev,
.driver = {
.name = "coresight-etm4x",
.of_match_table = etm4_sysreg_match,
+ .acpi_match_table = ACPI_PTR(etm4x_acpi_ids),
.suppress_bind_attrs = true,
.pm = &etm4_dev_pm_ops,
},
--
2.25.1
On Tue, May 23, 2023 at 10:15:47AM +0530, Anshuman Khandual wrote:
> CoreSight ETM4x devices could be accessed either via MMIO (handled via
> amba_driver) or CPU system instructions (handled via platform driver). But
> this has the following issues :
>
> - Each new CPU comes up with its own PID and thus we need to keep on
> adding the "known" PIDs to get it working with AMBA driver. While
> the ETM4 architecture (and CoreSight architecture) defines way to
> identify a device as ETM4. Thus older kernels won't be able to
> "discover" a newer CPU, unless we add the PIDs.
>
> - With ACPI, the ETM4x devices have the same HID to identify the device
> irrespective of the mode of access. This creates a problem where two
> different drivers (both AMBA based driver and platform driver) would
> hook into the "HID" and could conflict. e.g., if AMBA driver gets
> hold of a non-MMIO device, the probe fails. If we have single driver
> hooked into the given "HID", we could handle them seamlessly,
> irrespective of the mode of access.
>
> - CoreSight is heavily dependent on the runtime power management. With
> ACPI, amba_driver doesn't get us anywhere with handling the power
> and thus one need to always turn the power ON to use them. Moving to
> platform driver gives us the power management for free.
>
> Due to all of the above, we are moving ACPI MMIO based etm4x devices to be
> supported via tha platform driver. The series makes the existing platform
> driver generic to handle both type of the access modes. Although existing
> AMBA driver would still continue to support DT based etm4x MMIO devices.
> Although some problems still remain, such as manually adding PIDs for all
> new AMBA DT based devices.
>
> The series applies on 6.4-rc3.
>
Tested on Juno with some hacked up UEFI f/w.
Tested-by: Sudeep Holla <[email protected]>
--
Regards,
Sudeep