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SubjectRe: [PATCH v13 7/9] ACPI: Translate the I/O range of non-MMIO devices before scanning
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>> 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>
>

Hi Rafael,

Thanks for checking again.

> Just a few minor nits below.
>
>> ---
>> 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

>
>> + * @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

>
>> + * 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()?
>
>> + 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

>
>> + 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".

>
>> + 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.

>
>> + 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

>
>> + * 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

>> + 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

>> + 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

>
>> +
>> +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.

>
>> +}
>> +
>> +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 <rafael.j.wysocki@intel.com>
>
> for the generic ACPI changes.
>

Thanks,
John

> .
>


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