HISI LPC: Add ACPI support

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.
Tested-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Zhichang Yuan <yuanzhichang@hisilicon.com>
Signed-off-by: Gabriele Paoloni <gabriele.paoloni@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

drivers/bus/hisi_lpc.c

@@ -11,6 +11,7 @@
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/logic_pio.h>
+#include <linux/mfd/core.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
@@ -339,6 +340,203 @@ static const struct logic_pio_host_ops hisi_lpc_ops = {
 	.outs = hisi_lpc_comm_outs,
 };
 
+#ifdef CONFIG_ACPI
+#define MFD_CHILD_NAME_PREFIX DRV_NAME"-"
+#define MFD_CHILD_NAME_LEN (ACPI_ID_LEN + sizeof(MFD_CHILD_NAME_PREFIX) - 1)
+
+struct hisi_lpc_mfd_cell {
+	struct mfd_cell_acpi_match acpi_match;
+	char name[MFD_CHILD_NAME_LEN];
+	char pnpid[ACPI_ID_LEN];
+};
+
+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 = resource_size(res);
+
+	sys_port = logic_pio_trans_hwaddr(&host->fwnode, res->start, len);
+	if (sys_port == ~0UL)
+		return -EFAULT;
+
+	res->start = sys_port;
+	res->end = sys_port + len;
+
+	return 0;
+}
+
+/*
+ * hisi_lpc_acpi_set_io_res - set the resources for a child's MFD
+ * @child: the device node to be updated the I/O resource
+ * @hostdev: the device node associated with host controller
+ * @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 host controller, each child device will have an associated
+ * host-relative address resource.  This function will return the translated
+ * logical PIO addresses for each child devices resources.
+ */
+static int hisi_lpc_acpi_set_io_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;
+
+	if (!child || !hostdev)
+		return -EINVAL;
+
+	host = to_acpi_device(hostdev);
+	adev = to_acpi_device(child);
+
+	if (!adev->status.present) {
+		dev_dbg(child, "device is not present\n");
+		return -EIO;
+	}
+
+	if (acpi_device_enumerated(adev)) {
+		dev_dbg(child, "has been enumerated\n");
+		return -EIO;
+	}
+
+	/*
+	 * 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;
+	}
+
+	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);
+
+	/* translate the I/O resources */
+	for (i = 0; i < count; i++) {
+		int ret;
+
+		if (!(resources[i].flags & IORESOURCE_IO))
+			continue;
+		ret = hisi_lpc_acpi_xlat_io_res(adev, host, &resources[i]);
+		if (ret) {
+			dev_err(child, "translate IO range %pR failed (%d)\n",
+				&resources[i], ret);
+			return ret;
+		}
+	}
+	*res = resources;
+	*num_res = count;
+
+	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];
+	/* 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,
+		};
+
+		/*
+		 * For any instances of this host controller (Hip06 and Hip07
+		 * are the only chipsets), we would not have multiple slaves
+		 * with the same HID. And in any system we would have just one
+		 * controller active. So don't worrry about MFD name clashes.
+		 */
+		snprintf(name, MFD_CHILD_NAME_LEN, MFD_CHILD_NAME_PREFIX"%s",
+			 acpi_device_hid(child));
+		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,
+			      mfd_cells, cell_num, NULL, 0, NULL);
+	if (ret) {
+		dev_err(hostdev, "failed to add mfd cells (%d)\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct acpi_device_id hisi_lpc_acpi_match[] = {
+	{"HISI0191"},
+	{}
+};
+#else
+static int hisi_lpc_acpi_probe(struct device *dev)
+{
+	return -ENODEV;
+}
+#endif // CONFIG_ACPI
+
 /*
  * hisi_lpc_probe - the probe callback function for hisi lpc host,
  *		   will finish all the initialization.
@@ -383,11 +581,12 @@ static int hisi_lpc_probe(struct platform_device *pdev)
 	lpcdev->io_host = range;
 
 	/* register the LPC host PIO resources */
-	if (!acpi_device) {
+	if (acpi_device)
+		ret = hisi_lpc_acpi_probe(dev);
+	else
 		ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
-		if (ret)
-			return ret;
-	}
+	if (ret)
+		return ret;
 
 	lpcdev->io_host->hostdata = lpcdev;
 	lpcdev->io_host->ops = &hisi_lpc_ops;
@@ -409,6 +608,7 @@ static struct platform_driver hisi_lpc_driver = {
 	.driver = {
 		.name           = DRV_NAME,
 		.of_match_table = hisi_lpc_of_match,
+		.acpi_match_table = ACPI_PTR(hisi_lpc_acpi_match),
 	},
 	.probe = hisi_lpc_probe,
 };