From: Amey Narkhede <ameynarkhede03@gmail.com>
To: Shanker R Donthineni <sdonthineni@nvidia.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
alex.williamson@redhat.com,
Raphael Norwitz <raphael.norwitz@nutanix.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
kw@linux.com, Sinan Kaya <okaya@kernel.org>,
Len Brown <lenb@kernel.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>
Subject: Re: [PATCH v7 2/8] PCI: Add new array for keeping track of ordering of reset methods
Date: Mon, 21 Jun 2021 22:45:18 +0530 [thread overview]
Message-ID: <20210621171518.vs4h4y6ag2benlwp@archlinux> (raw)
In-Reply-To: <1fb0a184-908c-5f98-ef6d-74edc602c2e0@nvidia.com>
On 21/06/21 10:02AM, Shanker R Donthineni wrote:
> Hi Bjorn,
>
> On 6/18/21 12:22 PM, Amey Narkhede wrote:
> > I wonder if this would be easier if dev->reset_methods[] contained
> > indices into pci_reset_fn_methods[], highest priority first, with the
> > priority being determined when dev->reset_methods[] is updated. For
> > example:
> >
> > const struct pci_reset_fn_method pci_reset_fn_methods[] = {
> > { }, # 0
> > { &pci_dev_specific_reset, .name = "device_specific" }, # 1
> > { &pci_dev_acpi_reset, .name = "acpi" }, # 2
> > { &pcie_reset_flr, .name = "flr" }, # 3
> > { &pci_af_flr, .name = "af_flr" }, # 4
> > { &pci_pm_reset, .name = "pm" }, # 5
> > { &pci_reset_bus_function, .name = "bus" }, # 6
> > };
> >
> > dev->reset_methods[] = [1, 2, 3, 4, 5, 6]
> > means all reset methods are supported, in the default priority
> > order
> >
> > dev->reset_methods[] = [1, 0, 0, 0, 0, 0]
> > means only pci_dev_specific_reset is supported
> >
> > dev->reset_methods[] = [3, 5, 0, 0, 0, 0]
> > means pcie_reset_flr and pci_pm_reset are supported, in that
> > priority order
> What about keeping two bitmap fields 'resets_supported' and 'resets_enabled' in
> pci_dev object and mange it through sysfs and probe helper function. We can avoid
> two loops multiple paces and takes only 2Bytes of memory to keep track resets.
>
> resets_supported ---> initialized during pci_dev setup
> resets_enabled ---> Exposed to userspace through sysfs by default set to resets_supported
>
> include/linux/pci.h:
> ------------------------
> /* Different types of PCI resets possible, lower number is higher priority */
> #define PCI_RESET_METHOD_DEVSPEC 0
> #define PCI_RESET_METHOD_ACPI 1
> #define PCI_RESET_METHOD_FLR 2
> #define PCI_RESET_METHOD_Af_FLR 3
> #define PCI_RESET_METHOD_PM 4
> #define PCI_RESET_METHOD_BUS 5
> #define PCI_RESET_METHOD_MAX 6
>
> struct pci_dev {
> ...
> u8 resets_supported;
> u8 resets_enabled;
> };
>
> static inline bool pci_reset_supported(struct pci_dev *dev)
> {
> return !!(dev->resets_supported);
> }
>
>
> drivers/pci/pci.c:
> --------------------
> const struct pci_reset_fn_method pci_reset_fn_methods[PCI_RESET_METHOD_MAX] = {
> [PCI_RESET_METHOD_DEVSPEC] = { &pci_dev_specific_reset,
> .name = "device_specific" },
> [PCI_RESET_METHOD_ACPI] = { &pci_dev_acpi_reset, .name = "acpi" },
> [PCI_RESET_METHOD_FLR] = { &pcie_reset_flr, .name = "flr" },
> [PCI_RESET_METHOD_Af_FLR] = { &pci_af_flr, .name = "af_flr" },
> [PCI_RESET_METHOD_PM] = { &pci_pm_reset, .name = "pm" },
> [PCI_RESET_METHOD_BUS] = { &pci_reset_bus_function, .name = "bus" }
> };
>
>
> void pci_init_reset_methods(struct pci_dev *dev)
> {
> int i, rc;
>
> BUILD_BUG_ON(ARRAY_SIZE(pci_reset_fn_methods) != PCI_RESET_METHOD_MAX);
> might_sleep();
>
> for (i = 0; i < PCI_RESET_METHOD_MAX; i++) {
> rc = pci_reset_fn_methods[i].reset_fn(dev, PCI_RESET_PROBE);
> if (!rc)
> dev->resets_supported |= BIT(i);
> else if (rc != -ENOTTY)
> break;
> }
> dev->resets_enabled = dev->resets_supported;
> }
>
> int __pci_reset_function_locked(struct pci_dev *dev)
> {
> int i, rc = -ENOTTY;
>
> might_sleep();
>
> for (i = 0; i < PCI_RESET_METHOD_MAX; i++) {
> if (dev->resets_enabled & BIT(i)) {
> rc = pci_reset_fn_methods[i].reset_fn(dev, 0);
> if (rc != -ENOTTY)
> return rc;
> }
> }
>
> if (rc == -ENOTTY)
> pci_warn(dev, "No reset happened reason %s\n",
> !!dev->resets_supported ?
> "disabled by user" : "not supported");
>
> return rc;
> }
>
> drivers/pci/pci-sysfs.c
> ----------------------------
> static ssize_t reset_method_store(struct device *dev,
> struct device_attribute *attr,
> const char *buf, size_t count)
> {
> struct pci_dev *pdev = to_pci_dev(dev);
> u8 resets_enabled = 0;
> ...
> if (sysfs_streq(options, "default")) {
> pdev->resets_enabled = pdev->resets_supported;
> goto set_reset_methods;
> }
>
> while ((name = strsep(&options, ",")) != NULL) {
> if (sysfs_streq(name, ""))
> continue;
> name = strim(name);
>
> for (i = 0; i < PCI_RESET_METHOD_MAX; i++) {
> if ((pdev->resets_supported & BIT(i)) &&
> sysfs_streq(name, pci_reset_fn_methods[i].name)) {
> resets_enabled |= BIT(i);
> break;
> }
> }
> ...
> }
>
> set_reset_methods:
> kfree(options);
> pdev->resets_enabled = resets_enabled;
> return count;
> }
>
> static ssize_t reset_method_show(struct device *dev,
> struct device_attribute *attr,
> char *buf)
> {
> struct pci_dev *pdev = to_pci_dev(dev);
> ssize_t len = 0;
> int i;
>
> for (i = 0; i < PCI_RESET_METHOD_MAX; i++) {
> if (pdev->resets_enabled & BIT(i))
> len += sysfs_emit_at(buf, len, "%s%s",
> len ? "," : "",
> pci_reset_fn_methods[i].name);
> }
> len += sysfs_emit_at(buf, len, len ? "\n" : "");
>
> return len;
> }
>
Thank you for the idea.
Actually that would be coming full circle because Alex, Raphael and I
tried similar approach earlier while prototyping for v2 but this implementation
does look better than what I had at that time.
Thanks,
Amey
next prev parent reply other threads:[~2021-06-21 17:15 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-08 5:48 [PATCH v7 0/8] Expose and manage PCI device reset Amey Narkhede
2021-06-08 5:48 ` [PATCH v7 1/8] PCI: Add pcie_reset_flr to follow calling convention of other reset methods Amey Narkhede
2021-06-10 20:15 ` Shanker R Donthineni
2021-06-17 21:57 ` Bjorn Helgaas
2021-06-17 22:51 ` Alex Williamson
2021-06-18 16:32 ` Amey Narkhede
2021-06-24 12:23 ` Bjorn Helgaas
2021-06-24 15:28 ` Amey Narkhede
2021-06-24 16:15 ` Bjorn Helgaas
2021-06-24 18:48 ` Alex Williamson
2021-06-08 5:48 ` [PATCH v7 2/8] PCI: Add new array for keeping track of ordering of " Amey Narkhede
2021-06-10 20:15 ` Shanker R Donthineni
2021-06-17 23:13 ` Bjorn Helgaas
2021-06-18 17:22 ` Amey Narkhede
2021-06-21 15:02 ` Shanker R Donthineni
2021-06-21 17:15 ` Amey Narkhede [this message]
2021-06-21 18:37 ` Bjorn Helgaas
2021-06-08 5:48 ` [PATCH v7 3/8] PCI: Remove reset_fn field from pci_dev Amey Narkhede
2021-06-10 20:16 ` Shanker R Donthineni
2021-06-08 5:48 ` [PATCH v7 4/8] PCI/sysfs: Allow userspace to query and set device reset mechanism Amey Narkhede
2021-06-09 21:57 ` Raphael Norwitz
2021-06-09 22:36 ` Shanker R Donthineni
2021-06-09 22:48 ` Raphael Norwitz
2021-06-10 20:16 ` Shanker R Donthineni
2021-06-18 20:00 ` Bjorn Helgaas
2021-06-19 13:59 ` Amey Narkhede
2021-06-21 13:01 ` Bjorn Helgaas
2021-06-21 17:28 ` Amey Narkhede
2021-06-21 19:07 ` Bjorn Helgaas
2021-06-21 19:33 ` Amey Narkhede
2021-06-23 12:06 ` Bjorn Helgaas
2021-06-23 14:07 ` Amey Narkhede
2021-06-23 17:56 ` Amey Narkhede
2021-06-23 17:21 ` Alex Williamson
2021-06-24 12:15 ` Bjorn Helgaas
2021-06-24 15:12 ` Amey Narkhede
2021-06-24 16:56 ` Bjorn Helgaas
2021-06-24 17:20 ` Shanker R Donthineni
2021-06-24 17:28 ` Amey Narkhede
2021-06-24 17:59 ` Bjorn Helgaas
2021-06-08 5:48 ` [PATCH v7 5/8] PCI: Setup ACPI_COMPANION early Amey Narkhede
2021-06-08 5:48 ` [PATCH v7 6/8] PCI: Add support for ACPI _RST reset method Amey Narkhede
2021-06-08 5:48 ` [PATCH v7 7/8] PCI: Enable NO_BUS_RESET quirk for Nvidia GPUs Amey Narkhede
2021-06-10 23:16 ` Bjorn Helgaas
2021-06-10 23:33 ` Shanker R Donthineni
2021-06-10 23:43 ` Shanker R Donthineni
2021-06-10 23:53 ` Bjorn Helgaas
2021-06-11 4:15 ` Shanker R Donthineni
2021-06-08 5:48 ` [PATCH v7 8/8] PCI: Change the type of probe argument in reset functions Amey Narkhede
2021-06-09 21:40 ` Raphael Norwitz
2021-06-08 10:05 ` [PATCH v7 0/8] Expose and manage PCI device reset Enrico Weigelt, metux IT consult
2021-06-08 15:44 ` Amey Narkhede
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=20210621171518.vs4h4y6ag2benlwp@archlinux \
--to=ameynarkhede03@gmail.com \
--cc=alex.williamson@redhat.com \
--cc=helgaas@kernel.org \
--cc=kw@linux.com \
--cc=lenb@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=okaya@kernel.org \
--cc=raphael.norwitz@nutanix.com \
--cc=rjw@rjwysocki.net \
--cc=sdonthineni@nvidia.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: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).