quoted

Signed-off-by: John Garry <redacted>
Signed-off-by: Zhichang Yuan <redacted>
Signed-off-by: Gabriele Paoloni <redacted>

Hi Rafael,

Thanks for checking again.

Just a few minor nits below.

quoted

---
 drivers/acpi/arm64/Makefile          |   1 +
 drivers/acpi/arm64/acpi_indirectio.c | 250 +++++++++++++++++++++++++++++++++++
 drivers/acpi/internal.h              |   5 +
 drivers/acpi/scan.c                  |   1 +
 4 files changed, 257 insertions(+)
 create mode 100644 drivers/acpi/arm64/acpi_indirectio.c

diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
index 1017def..f4a7f46 100644
--- a/drivers/acpi/arm64/Makefile
+++ b/drivers/acpi/arm64/Makefile

@@ -1,2 +1,3 @@
 obj-$(CONFIG_ACPI_IORT)        += iort.o
 obj-$(CONFIG_ACPI_GTDT)        += gtdt.o
+obj-$(CONFIG_INDIRECT_PIO)     += acpi_indirectio.o

diff --git a/drivers/acpi/arm64/acpi_indirectio.c b/drivers/acpi/arm64/acpi_indirectio.c
new file mode 100644
index 0000000..51a1b92
--- /dev/null
+++ b/drivers/acpi/arm64/acpi_indirectio.c

@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017 HiSilicon Limited, All Rights Reserved.
+ * Author: Gabriele Paoloni <gabriele.paoloni@huawei.com>
+ * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>
+ * Author: John Garry <john.garry@huawei.com>
+ *
+ * This file implements functunality to scan the ACPI namespace and config
+ * devices under "indirect IO" hosts. An "indirect IO" host allows child
+ * devices to use logical IO accesses when the host, itself, does not provide
+ * a transparent bridge. The device setup creates a per-child MFD with a
+ * logical port IO resource.
+ */
+
+#include <linux/acpi.h>
+#include <linux/logic_pio.h>
+#include <linux/mfd/core.h>
+#include <linux/platform_device.h>
+
+ACPI_MODULE_NAME("indirect IO");
+
+#define ACPI_INDIRECT_IO_NAME_LEN 255
+
+struct acpi_indirect_io_mfd_cell {
+       struct mfd_cell_acpi_match acpi_match;
+       char name[ACPI_INDIRECT_IO_NAME_LEN];
+       char pnpid[ACPI_INDIRECT_IO_NAME_LEN];
+};
+
+static int acpi_indirect_io_xlat_res(struct acpi_device *adev,
+                                    struct acpi_device *host,
+                                    struct resource *res)
+{
+       unsigned long sys_port;
+       resource_size_t len = res->end - res->start;
+
+       sys_port = logic_pio_trans_hwaddr(&host->fwnode, res->start, len);
+       if (sys_port == -1UL)
+               return -EFAULT;
+
+       res->start = sys_port;
+       res->end = sys_port + len;
+
+       return 0;
+}
+
+/*
+ * acpi_indirect_io_set_res - set the resources for a child device
+ * (MFD) of an "indirect IO" host.

The above should fit into a single line.

I'd make it something like "acpi_indirect_io_set_res - set "indirect
IO" host child (MFD) resources" and it already is explained in the
comment below.

Fine

quoted

+ * @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

host-relative

right

quoted

+ * 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);
+
+       /* check the device state */
+       if (!adev->status.present) {
+               dev_info(child, "device is not present\n");

dev_dbg()?

quoted

+               return 0;
+       }
+       /* whether the child had been enumerated? */
+       if (acpi_device_enumerated(adev)) {
+               dev_info(child, "had been enumerated\n");

Again, dev_dbg()?

sure, I think that these can be downgraded

quoted

+               return 0;
+       }
+
+       count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
+       if (count <= 0) {
+               dev_err(child, "failed to get resources\n");

I'd use dev_dbg() here too (the message may not even be meaningful to a user).

I think that it could be ok - having no resources is not really an "error".

quoted

+               return count ? count : -EIO;
+       }
+
+       resources = kcalloc(count, sizeof(*resources), GFP_KERNEL);
+       if (!resources) {

And you don't print anything here, I wonder why?

As I see, we generally don't print out-of-memory failure as we expect 
the alloc code to do it.

But I agree it's useful as we know the point of failure in the driver 
and can add diagnostic info like count value, as maybe we're trying to 
allocate a huge amount of memory.

quoted

+               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++) {
+               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;
+}
+
+/*
+ * acpi_indirect_io_setup - scan handler for "indirect IO" host.
+ * @adev: "indirect IO" host ACPI device pointer

One extra empty comment line here, please.

ok

quoted

+ * 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];
+               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));
+               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);

Again, please consider using dev_dbg() here and below (for the same
reason as above).

well if this happens the device is not enumerated, so I think a warn may 
be more appropiate

quoted

+                       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");

as above

quoted

+               ret = PTR_ERR(pdev);
+               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;

return 0;

You know that ret must be 0 here anyway.

yes, I prefer this

quoted

+
+free_mfd_resources:
+       while (cell_num--)
+               kfree(mfd_cells[cell_num].resources);
+       kfree(mfd_cells);
+free_range:
+       kfree(range);
+
+       return ret;
+}
+
+/* All the host devices which apply indirect-IO can be listed here. */
+static const struct acpi_device_id acpi_indirect_io_host_id[] = {
+       {}
+};
+
+static int acpi_indirect_io_attach(struct acpi_device *adev,
+                                  const struct acpi_device_id *id)
+{
+       int ret = acpi_indirect_io_setup(adev);
+
+       if (ret < 0)
+               return ret;
+
+       return 1;

The above can be written as

return ret < 0 ? ret : 1;

to save a few lines of code (you are using this pattern above, so why
not here?).

I can change it.

quoted

+}
+
+static struct acpi_scan_handler acpi_indirect_io_handler = {
+       .ids = acpi_indirect_io_host_id,
+       .attach = acpi_indirect_io_attach,
+};
+
+void __init acpi_indirect_io_scan_init(void)
+{
+       acpi_scan_add_handler(&acpi_indirect_io_handler);
+}

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 1d0a501..680f3cf 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h

@@ -31,6 +31,11 @@
 void acpi_platform_init(void);
 void acpi_pnp_init(void);
 void acpi_int340x_thermal_init(void);
+#ifdef CONFIG_INDIRECT_PIO
+void acpi_indirect_io_scan_init(void);
+#else
+static inline void acpi_indirect_io_scan_init(void) {}
+#endif
 #ifdef CONFIG_ARM_AMBA
 void acpi_amba_init(void);
 #else

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 8e63d93..204da8a 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c

@@ -2155,6 +2155,7 @@ int __init acpi_scan_init(void)
        acpi_amba_init();
        acpi_watchdog_init();
        acpi_init_lpit();
+       acpi_indirect_io_scan_init();

        acpi_scan_add_handler(&generic_device_handler);

--

But generally

Acked-by: Rafael J. Wysocki <redacted>

for the generic ACPI changes.

Thanks,
John

.