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Message-ID: <1519933855.10722.364.camel@linux.intel.com>
Date: Thu, 01 Mar 2018 21:50:55 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: John Garry <john.garry@...wei.com>,
mika.westerberg@...ux.intel.com, rafael@...nel.org,
lorenzo.pieralisi@....com, rjw@...ysocki.net,
hanjun.guo@...aro.org, robh+dt@...nel.org, bhelgaas@...gle.com,
arnd@...db.de, mark.rutland@....com, olof@...om.net,
dann.frazier@...onical.com, andy.shevchenko@...il.com,
robh@...nel.org
Cc: joe@...ches.com, benh@...nel.crashing.org,
linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-acpi@...r.kernel.org, linuxarm@...wei.com, minyard@....org,
devicetree@...r.kernel.org, linux-arch@...r.kernel.org,
rdunlap@...radead.org, gregkh@...uxfoundation.org,
akpm@...ux-foundation.org, frowand.list@...il.com, agraf@...e.de
Subject: Re: [PATCH v15 8/9] HISI LPC: Add ACPI support
On Tue, 2018-02-27 at 00:40 +0800, John Garry wrote:
> Based on the previous patches, this patch supports the
> LPC host on hip06/hip07 for ACPI FW.
>
> It is the responsibility of the LPC host driver to
> enumerate the child devices, as the ACPI scan code will
> not enumerate children of "indirect IO" hosts.
>
> The ACPI table for the LPC host controller and the child
> devices is in the following format:
> Device (LPC0) {
> Name (_HID, "HISI0191") // HiSi LPC
> Name (_CRS, ResourceTemplate () {
> Memory32Fixed (ReadWrite, 0xa01b0000, 0x1000)
> })
> }
>
> Device (LPC0.IPMI) {
> Name (_HID, "IPI0001")
> Name (LORS, ResourceTemplate() {
> QWordIO (
> ResourceConsumer,
> MinNotFixed, // _MIF
> MaxNotFixed, // _MAF
> PosDecode,
> EntireRange,
> 0x0, // _GRA
> 0xe4, // _MIN
> 0x3fff, // _MAX
> 0x0, // _TRA
> 0x04, // _LEN
> , ,
> BTIO
> )
> })
>
> Since the IO resources of the child devices need to be
> translated from LPC bus addresses to logical PIO addresses,
> and we shouldn't modify the resources of the devices
> generated in the FW scan, a per-child MFD is created as
> a substitute. The MFD IO resources will be the translated
> bus addresses of the ACPI child.
Ok, this needs to be thought about a bit more.
I guess I understand what's is the problem with PNP IDs in the driver.
You probe your LPC device quite late.
One option is to move from classical probe to a event-driven model, i.e.
via registering a notifier (see acpi_lpss.c), preparing necessary stuff
at earlier stages and then register devices by their enumeration and
appearance.
Though, if I would be you I would seek a opinion from Rafael and Mika
(maybe others as well).
See also some comments below.
> +#ifdef CONFIG_ACPI
> +#define MFD_CHILD_NAME_PREFIX DRV_NAME"-"
> +#define MFD_CHILD_NAME_LEN (ACPI_ID_LEN +
> sizeof(MFD_CHILD_NAME_PREFIX))
..._PREFIX) - 1)
?
> +static int hisi_lpc_acpi_xlat_io_res(struct acpi_device *adev,
> + struct acpi_device *host,
> + struct resource *res)
> +{
> + unsigned long sys_port;
> + resource_size_t len = res->end - res->start;
resource_size()
> + return 0;
> +}
> +static int hisi_lpc_acpi_set_io_res(struct device *child,
> + struct device *hostdev,
> + const struct resource **res,
> + int *num_res)
> +{
> + /*
> + * The following code segment to retrieve the resources is
> common to
> + * acpi_create_platform_device(), so consider a common helper
> function
> + * in future.
> + */
> + count = acpi_dev_get_resources(adev, &resource_list, NULL,
> NULL);
> + if (count <= 0) {
> + dev_dbg(child, "failed to get resources\n");
> + return count ? count : -EIO;
count == 0 --> return 0;
Is it by design? (I didn't check acpi_create_platform_device() though)
> + }
> +
> + resources = devm_kcalloc(hostdev, count, sizeof(*resources),
> + GFP_KERNEL);
> + if (!resources) {
> + dev_warn(hostdev, "could not allocate memory for %d
> resources\n",
> + count);
> + acpi_dev_free_resource_list(&resource_list);
> + return -ENOMEM;
> + }
> + count = 0;
> + list_for_each_entry(rentry, &resource_list, node)
> + resources[count++] = *rentry->res;
> +
> + acpi_dev_free_resource_list(&resource_list);
> +
> + return 0;
> +}
> +
> +/*
> + * hisi_lpc_acpi_probe - probe children for ACPI FW
> + * @hostdev: LPC host device pointer
> + *
> + * Returns 0 when successful, and a negative value for failure.
> + *
> + * Scan all child devices and create a per-device MFD with
> + * logical PIO translated IO resources.
> + */
> +static int hisi_lpc_acpi_probe(struct device *hostdev)
> +{
> + struct acpi_device *adev = ACPI_COMPANION(hostdev);
> + struct hisi_lpc_mfd_cell *hisi_lpc_mfd_cells;
> + struct mfd_cell *mfd_cells;
> + struct acpi_device *child;
> + int size, ret, count = 0, cell_num = 0;
> +
> + list_for_each_entry(child, &adev->children, node)
> + cell_num++;
> +
> + /* allocate the mfd cell and companion acpi info, one per
> child */
> + size = sizeof(*mfd_cells) + sizeof(*hisi_lpc_mfd_cells);
> + mfd_cells = devm_kcalloc(hostdev, cell_num, size,
> GFP_KERNEL);
> + if (!mfd_cells)
> + return -ENOMEM;
> +
> + hisi_lpc_mfd_cells = (struct hisi_lpc_mfd_cell *)
> + &mfd_cells[cell_num];
One line, please.
Just noticed that calloc() memory layout is not the same how you are
using it.
> + /* Only consider the children of the host */
> + list_for_each_entry(child, &adev->children, node) {
> + struct mfd_cell *mfd_cell = &mfd_cells[count];
> + struct hisi_lpc_mfd_cell *hisi_lpc_mfd_cell =
> + &hisi_lpc_mfd_cells[count];
> + struct mfd_cell_acpi_match *acpi_match =
> + &hisi_lpc_mfd_cell-
> >acpi_match;
> + char *name = hisi_lpc_mfd_cell[count].name;
> + char *pnpid = hisi_lpc_mfd_cell[count].pnpid;
> + struct mfd_cell_acpi_match match = {
> + .pnpid = pnpid,
> + };
> +
> + snprintf(name, MFD_CHILD_NAME_LEN,
> MFD_CHILD_NAME_PREFIX"%s",
> + acpi_device_hid(child));
No possibility of identical devices?
> + snprintf(pnpid, ACPI_ID_LEN, "%s",
> acpi_device_hid(child));
> +
> + memcpy(acpi_match, &match, sizeof(*acpi_match));
> + mfd_cell->name = name;
> + mfd_cell->acpi_match = acpi_match;
> +
> + ret = hisi_lpc_acpi_set_io_res(&child->dev, &adev-
> >dev,
> + &mfd_cell->resources,
> + &mfd_cell-
> >num_resources);
> + if (ret) {
> + dev_warn(&child->dev, "set resource
> fail(%d)\n", ret);
> + return ret;
> + }
> + count++;
> + }
> +
> + ret = mfd_add_devices(hostdev,
> PLATFORM_DEVID_NONE,
You mean it's not possible to have more than one identical device?
> + mfd_cells, cell_num, NULL, 0, NULL);
> + if (ret) {
> + dev_err(hostdev, "failed to add mfd cells (%d)\n",
> ret);
> + return ret;
> + }
--
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy
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