On Mon, Mar 24, 2025 at 03:01:49PM +0200, Ilpo Järvinen wrote: > On Mon, 24 Mar 2025, Manivannan Sadhasivam via B4 Relay wrote: > > > From: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > > > Precision Time Management (PTM) mechanism defined in PCIe spec r6.0, > > sec 6.22 allows precise coordination of timing information across multiple > > components in a PCIe hierarchy with independent local time clocks. > > Hi Mani, > > PCIe r6.0.1 sec 6.22 is about Readiness Notification (RN) and PTM is 6.21, > did you perhaps mistype the section number? > Oops, yeah. I referred the PCIe 5.0 spec, but mistakenly quoted 6.0. Will fix it. > > PCI core already supports enabling PTM in the root port and endpoint > > devices through PTM Extended Capability registers. But the PTM context > > supported by the PTM capable components such as Root Complex (RC) and > > Endpoint (EP) controllers were not exposed as of now. > > > > Hence, add the sysfs support to expose the PTM context to userspace from > > both PCIe RC and EP controllers. Controller drivers are expected to call > > pcie_ptm_create_sysfs() to create the sysfs attributes for the PTM context > > and call pcie_ptm_destroy_sysfs() to destroy them. The drivers should also > > populate the relevant callbacks in the 'struct pcie_ptm_ops' structure > > based on the controller implementation. > > > > Below PTM context are exposed through sysfs: > > > > PCIe RC > > ======= > > > > 1. PTM Local clock > > 2. PTM T2 timestamp > > 3. PTM T3 timestamp > > 4. PTM Context valid > > > > PCIe EP > > ======= > > > > 1. PTM Local clock > > 2. PTM T1 timestamp > > 3. PTM T4 timestamp > > 4. PTM Master clock > > 5. PTM Context update > > > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > --- > > Documentation/ABI/testing/sysfs-platform-pcie-ptm | 70 ++++++ > > MAINTAINERS | 1 + > > drivers/pci/pcie/ptm.c | 268 ++++++++++++++++++++++ > > include/linux/pci.h | 35 +++ > > 4 files changed, 374 insertions(+) > > > > diff --git a/Documentation/ABI/testing/sysfs-platform-pcie-ptm b/Documentation/ABI/testing/sysfs-platform-pcie-ptm > > new file mode 100644 > > index 0000000000000000000000000000000000000000..010c3e32e2b8eaf352a8e1aad7420d8a3e948dae > > --- /dev/null > > +++ b/Documentation/ABI/testing/sysfs-platform-pcie-ptm > > @@ -0,0 +1,70 @@ > > +What: /sys/devices/platform/*/ptm/local_clock > > +Date: February 2025 > > +Contact: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > +Description: > > + (RO) PTM local clock in nanoseconds. Applicable for both Root > > + Complex and Endpoint controllers. > > + > > +What: /sys/devices/platform/*/ptm/master_clock > > +Date: February 2025 > > +Contact: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > +Description: > > + (RO) PTM master clock in nanoseconds. Applicable only for > > + Endpoint controllers. > > + > > +What: /sys/devices/platform/*/ptm/t1 > > +Date: February 2025 > > +Contact: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > +Description: > > + (RO) PTM T1 timestamp in nanoseconds. Applicable only for > > + Endpoint controllers. > > + > > +What: /sys/devices/platform/*/ptm/t2 > > +Date: February 2025 > > +Contact: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > +Description: > > + (RO) PTM T2 timestamp in nanoseconds. Applicable only for > > + Root Complex controllers. > > + > > +What: /sys/devices/platform/*/ptm/t3 > > +Date: February 2025 > > +Contact: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > +Description: > > + (RO) PTM T3 timestamp in nanoseconds. Applicable only for > > + Root Complex controllers. > > + > > +What: /sys/devices/platform/*/ptm/t4 > > +Date: February 2025 > > +Contact: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > +Description: > > + (RO) PTM T4 timestamp in nanoseconds. Applicable only for > > + Endpoint controllers. > > + > > +What: /sys/devices/platform/*/ptm/context_update > > +Date: February 2025 > > +Contact: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > +Description: > > + (RW) Control the PTM context update mode. Applicable only for > > + Endpoint controllers. > > + > > + Following values are supported: > > + > > + * auto = PTM context auto update trigger for every 10ms > > + > > + * manual = PTM context manual update. Writing 'manual' to this > > + file triggers PTM context update (default) > > + > > +What: /sys/devices/platform/*/ptm/context_valid > > +Date: February 2025 > > +Contact: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > +Description: > > + (RW) Control the PTM context validity (local clock timing). > > + Applicable only for Root Complex controllers. PTM context is > > + invalidated by hardware if the Root Complex enters low power > > + mode or changes link frequency. > > + > > + Following values are supported: > > + > > + * 0 = PTM context invalid (default) > > + > > + * 1 = PTM context valid > > diff --git a/MAINTAINERS b/MAINTAINERS > > index b4d09d52a750b320f689c1365791cdfa6e719fde..f1bac092877df739328347481bd14f6701a7df19 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -18213,6 +18213,7 @@ Q: https://patchwork.kernel.org/project/linux-pci/list/ > > B: https://bugzilla.kernel.org > > C: irc://irc.oftc.net/linux-pci > > T: git git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git > > +F: Documentation/ABI/testing/sysfs-platform-pcie-ptm > > F: Documentation/devicetree/bindings/pci/ > > F: drivers/pci/controller/ > > F: drivers/pci/pci-bridge-emul.c > > diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c > > index 7cfb6c0d5dcb6de2a759b56d6877c95102b3d10f..bfa632b76a87ad304e966a8edfb5dba14d58a23c 100644 > > --- a/drivers/pci/pcie/ptm.c > > +++ b/drivers/pci/pcie/ptm.c > > @@ -10,6 +10,8 @@ > > #include <linux/pci.h> > > #include "../pci.h" > > > > +struct device *ptm_device; > > + > > /* > > * If the next upstream device supports PTM, return it; otherwise return > > * NULL. PTM Messages are local, so both link partners must support it. > > @@ -252,3 +254,269 @@ bool pcie_ptm_enabled(struct pci_dev *dev) > > return dev->ptm_enabled; > > } > > EXPORT_SYMBOL(pcie_ptm_enabled); > > + > > +static ssize_t context_update_store(struct device *dev, > > + struct device_attribute *attr, > > + const char *buf, size_t count) > > +{ > > + struct pcie_ptm *ptm = dev_get_drvdata(dev); > > + int ret; > > + > > + if (!ptm->ops->context_update_store) > > + return -EOPNOTSUPP; > > + > > + ret = ptm->ops->context_update_store(ptm->pdata, buf); > > Do these store funcs need some locking? Who is responsible about it? > Good catch! I obviously missed the locking here. > Why isn't buf parsed here and converted to some define/enum values, what > is the advantage of passing it on as char *? > Only because I was not sure if the values are going to be the same across all implementations. But since I document 'auto' and 'manual' in ABI documentation, I think it makes sense to pass the values directly. - Mani -- மணிவண்ணன் சதாசிவம்
