On 14/02/2018 13:53, Andy Shevchenko wrote:
On Tue, Feb 13, 2018 at 7:45 PM, John Garry <john.garry@xxxxxxxxxx> wrote:
On some platforms (such as arm64-based hip06/hip07), access to legacy
ISA/LPC devices through access IO space is required, similar to x86
platforms. As the I/O for these devices are not memory mapped like
PCI/PCIE MMIO host bridges, they require special low-level device
operations through some host to generate IO accesses, i.e. a non-
transparent bridge.
Through the logical PIO framework, hosts are able to register address
ranges in the logical PIO space for IO accesses. For hosts which require
a LLDD to generate the IO accesses, through the logical PIO framework
the host also registers accessors as a backend to generate the physical
bus transactions for IO space accesses (called indirect IO).
When describing the indirect IO child device in APCI tables, the IO
resource is the host-specific address for the child (generally a
bus address).
An example is as follows:
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 resource for the child is a host-specific address,
special translation are required to retrieve the logical PIO address
for that child.
To overcome the problem of associating this logical PIO address
with the child device, a scan handler is added to scan the ACPI
namespace for known indirect IO hosts. This scan handler creates an
MFD per child with the translated logical PIO address as it's IO
resource, as a substitute for the normal platform device which ACPI
would create during device enumeration.
Hi Andy,
+ unsigned long sys_port;
+ sys_port = logic_pio_trans_hwaddr(&host->fwnode, res->start, len);
+ if (sys_port == -1UL)
Wouldn't it be better to compare with ULONG_MAX?
Could do, being the same thing. Maybe people prefer -1UL as it saves
having to figure out what ULONG_MAX is :)
+ return -EFAULT;
+/*
Shouldn't be a kernel-doc?
Right, I'll make it /**
+ * acpi_indirect_io_set_res - set the resources for a child device
+ * (MFD) of an "indirect IO" host.
In that case this would be one line w/o period at the end.
+ * @child: the device node to be updated the I/O resource
+ * @hostdev: the device node associated with the "indirect IO" host
+ * @res: double pointer to be set to the address of translated resources
+ * @num_res: pointer to variable to hold the number of translated resources
+ *
+ * Returns 0 when successful, and a negative value for failure.
+ *
+ * For a given "indirect IO" host, each child device will have associated
+ * host-relevative address resource. This function will return the translated
+ * logical PIO addresses for each child devices resources.
+ */
+static int acpi_indirect_io_set_res(struct device *child,
+ struct device *hostdev,
+ const struct resource **res,
+ int *num_res)
+{
+ struct acpi_device *adev;
+ struct acpi_device *host;
+ struct resource_entry *rentry;
+ LIST_HEAD(resource_list);
+ struct resource *resources;
+ int count;
+ int i;
+ int ret = -EIO;
+
+ if (!child || !hostdev)
+ return -EINVAL;
+
+ host = to_acpi_device(hostdev);
+ adev = to_acpi_device(child);
***
+ count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
+ if (count <= 0) {
+ dev_err(child, "failed to get resources\n");
+ return count ? count : -EIO;
+ }
+
+ resources = kcalloc(count, sizeof(*resources), GFP_KERNEL);
+ if (!resources) {
+ 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);
It has similarities with acpi_create_platform_device().
I guess we can utilize existing code.
For sure, this particular segment is effectively same as part of
acpi_create_platform_device():
struct platform_device *acpi_create_platform_device(struct acpi_device
*adev,
struct property_entry *properties)
{
struct platform_device *pdev = NULL;
struct platform_device_info pdevinfo;
struct resource_entry *rentry;
struct list_head resource_list;
struct resource *resources = NULL;
int count;
/* If the ACPI node already has a physical device attached, skip it. */
if (adev->physical_node_count)
return NULL;
if (!acpi_match_device_ids(adev, forbidden_id_list))
return ERR_PTR(-EINVAL);
***>
INIT_LIST_HEAD(&resource_list);
count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
if (count < 0) {
return NULL;
} else if (count > 0) {
resources = kzalloc(count * sizeof(struct resource),
GFP_KERNEL);
if (!resources) {
dev_err(&adev->dev, "No memory for resources\n");
acpi_dev_free_resource_list(&resource_list);
return ERR_PTR(-ENOMEM);
}
count = 0;
list_for_each_entry(rentry, &resource_list, node)
acpi_platform_fill_resource(adev, rentry->res,
&resources[count++]);
acpi_dev_free_resource_list(&resource_list);
}
<****
memset(&pdevinfo, 0, sizeof(pdevinfo));
/*
* If the ACPI node has a parent and that parent has a physical
So is your idea to refactor this common segment into a helper function?
+ /* translate the I/O resources */
+ for (i = 0; i < count; i++) {
+ if (!(resources[i].flags & IORESOURCE_IO))
+ continue;
+ ret = acpi_indirect_io_xlat_res(adev, host, &resources[i]);
+ if (ret) {
+ kfree(resources);
+ dev_err(child, "translate IO range failed(%d)\n", ret);
+ return ret;
+ }
+ }
+ *res = resources;
+ *num_res = count;
+
+ return ret;
Perhaps,
ret = ...
if (ret)
break;
}
if (ret) {
kfree(resources);
dev_err(child, "translate IO range failed(%d)\n", ret);
return ret;
}
*res = resources;
*num_res = count;
return 0;
seems fine
?
+}
+
+/*
+ * acpi_indirect_io_setup - scan handler for "indirect IO" host.
+ * @adev: "indirect IO" host ACPI device pointer
+ * Returns 0 when successful, and a negative value for failure.
+ *
+ * Setup an "indirect IO" host by scanning all child devices, and
+ * create a per-device MFD with logical PIO translated IO resources.
+ */
+static int acpi_indirect_io_setup(struct acpi_device *adev)
+{
+ struct platform_device *pdev;
+ struct mfd_cell *mfd_cells;
+ struct logic_pio_hwaddr *range;
+ struct acpi_device *child;
+ struct acpi_indirect_io_mfd_cell *acpi_indirect_io_mfd_cells;
+ int size, ret, count = 0, cell_num = 0;
+
+ range = kzalloc(sizeof(*range), GFP_KERNEL);
+ if (!range)
+ return -ENOMEM;
+ range->fwnode = &adev->fwnode;
+ range->flags = PIO_INDIRECT;
+ range->size = PIO_INDIRECT_SIZE;
+
+ ret = logic_pio_register_range(range);
+ if (ret)
+ goto free_range;
+
+ 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(*acpi_indirect_io_mfd_cells);
+ mfd_cells = kcalloc(cell_num, size, GFP_KERNEL);
+ if (!mfd_cells) {
+ ret = -ENOMEM;
+ goto free_range;
+ }
+
+ acpi_indirect_io_mfd_cells = (struct acpi_indirect_io_mfd_cell *)
+ &mfd_cells[cell_num];
+ /* Only consider the children of the host */
+ list_for_each_entry(child, &adev->children, node) {
+ struct mfd_cell *mfd_cell = &mfd_cells[count];
+ struct acpi_indirect_io_mfd_cell *acpi_indirect_io_mfd_cell =
+ &acpi_indirect_io_mfd_cells[count];
+ const struct mfd_cell_acpi_match *acpi_match =
+ &acpi_indirect_io_mfd_cell->acpi_match;
+ char *name = &acpi_indirect_io_mfd_cell[count].name[0];
+ char *pnpid = &acpi_indirect_io_mfd_cell[count].pnpid[0];
Plain x is equivalent to &x[0].
Right, but I thought for arrays that we should use address of x rather
than x itself, no?
+ struct mfd_cell_acpi_match match = {
+ .pnpid = pnpid,
+ };
+
+ snprintf(name, ACPI_INDIRECT_IO_NAME_LEN, "indirect-io-%s",
+ acpi_device_hid(child));
+ snprintf(pnpid, ACPI_INDIRECT_IO_NAME_LEN, "%s",
+ acpi_device_hid(child))
+ memcpy((void *)acpi_match, (void *)&match, sizeof(*acpi_match));
Casting to void * is pointless. In both cases.
I rechecked this. The casting to void * was there to mask another issue
which I've now fixed.
+ mfd_cell->name = name;
+ mfd_cell->acpi_match = acpi_match;
+
+ ret = acpi_indirect_io_set_res(&child->dev, &adev->dev,
+ &mfd_cell->resources,
+ &mfd_cell->num_resources);
+ if (ret) {
+ dev_err(&child->dev, "set resource failed (%d)\n", ret);
+ goto free_mfd_resources;
+ }
+ count++;
+ }
+
+ pdev = acpi_create_platform_device(adev, NULL);
+ if (IS_ERR_OR_NULL(pdev)) {
+ dev_err(&adev->dev, "create platform device for host failed\n");
+ ret = PTR_ERR(pdev);
So, NULL case will return 0. Is it expected?
Should error in that case also, so I'll change.
+ goto free_mfd_resources;
+ }
+ acpi_device_set_enumerated(adev);
+
+ ret = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE,
+ mfd_cells, cell_num, NULL, 0, NULL);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to add mfd cells (%d)\n", ret);
+ goto free_mfd_resources;
+ }
+
+ return ret;
+
+free_mfd_resources:
+ while (cell_num--)
+ kfree(mfd_cells[cell_num].resources);
+ kfree(mfd_cells);
+free_range:
+ kfree(range);
+
+ return ret;
+}
One question, what a scope of use of this function? Is it ->probe() time?
If it's so, can we use devm_* variants?
It is called from a scan handler, so prior to device probing.
Thanks,
John
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