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Date: Thu, 4 Aug 2022 19:26:27 +0100
From: Robin Murphy <robin.murphy@....com>
To: Lorenzo Pieralisi <lpieralisi@...nel.org>,
Jianmin Lv <lvjianmin@...ngson.cn>
Cc: guohanjun@...wei.com, sudeep.holla@....com, rafael@...nel.org,
lenb@...nel.org, robert.moore@...el.com,
linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [PATCH] ACPI / scan: Support multiple dma windows with different
offsets
On 04/08/2022 2:27 pm, Lorenzo Pieralisi wrote:
> [+Robin]
>
> On Thu, Aug 04, 2022 at 05:59:23PM +0800, Jianmin Lv wrote:
>> Hi, all
>>
>> Can anybody help to review the patch, or I missed somebody else?
>
> I will review the patch - added Robin since it affects the DMA
> ranges handling.
Thanks Lorenzo!
>
> Lorenzo
>
>> Thanks!
>>
>> On 2022/7/31 下午4:17, Jianmin Lv wrote:
>>> For DT, of_dma_get_range returns bus_dma_region typed dma regions,
>>> which makes multiple dma windows with different offset available
>>> for translation between dma address and cpu address.
>>>
>>> But for ACPI, acpi_dma_get_range doesn't return similar dma regions,
>>> causing no path for setting dev->dma_range_map conveniently. So the
>>> patch changes acpi_dma_get_range and returns bus_dma_region typed
>>> dma regions according to of_dma_get_range.
>>>
>>> After changing acpi_dma_get_range, original part of internal code
>>> only available for ARM is moved to acpi_arch_dma_setup for remaining
>>> unchanged.
This seems a bit silly. If we've finally done the work to parse a proper
dma_range_map, we can use it; no need to artificially maintain the old
dma_pfn_offset limitation. TBH I wouldn't even preserve the dmaaddr and
size calculations as they are either, just set dev->bus_dma_limit based
on the highest entry in the map, and pass 0 and U64_MAX to
arch_setup_dma_ops() since those are basically meaningless now (I plan
to remove them entirely once I unpick the IOMMU setup).
Thanks,
Robin.
>>> Signed-off-by: Jianmin Lv <lvjianmin@...ngson.cn>
>>>
>>> diff --git a/drivers/acpi/arm64/dma.c b/drivers/acpi/arm64/dma.c
>>> index f16739a..840f918 100644
>>> --- a/drivers/acpi/arm64/dma.c
>>> +++ b/drivers/acpi/arm64/dma.c
>>> @@ -9,6 +9,7 @@ void acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
>>> int ret;
>>> u64 end, mask;
>>> u64 dmaaddr = 0, size = 0, offset = 0;
>>> + const struct bus_dma_region *map = NULL;
>>> /*
>>> * If @dev is expected to be DMA-capable then the bus code that created
>>> @@ -26,10 +27,37 @@ void acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
>>> else
>>> size = 1ULL << 32;
>>> - ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
>>> + ret = acpi_dma_get_range(dev, &map);
>>> if (ret == -ENODEV)
>>> ret = iort_dma_get_ranges(dev, &size);
>>> if (!ret) {
>>> + const struct bus_dma_region *r = map;
>>> + u64 len, dma_start, dma_end = 0;
>>> +
>>> + /* determine the overall bounds of all dma regions */
>>> + for (dma_start = U64_MAX; r->size; r++) {
>>> + if (offset && r->offset != offset) {
>>> + dev_warn(dev, "Can't handle multiple windows with different offsets\n");
>>> + return;
>>> + }
>>> + offset = r->offset;
>>> +
>>> + /* Take lower and upper limits */
>>> + if (r->dma_start < dma_start)
>>> + dma_start = r->dma_start;
>>> + if (r->dma_start + r->size - 1 > dma_end)
>>> + dma_end = r->dma_start + r->size - 1;
>>> + }
>>> +
>>> + if (dma_start >= dma_end) {
>>> + dev_dbg(dev, "Invalid DMA regions configuration\n");
>>> + return;
>>> + }
>>> +
>>> + dmaaddr = dma_start;
>>> + len = dma_end - dma_start;
>>> + size = max(len, len + 1);
>>> +
>>> /*
>>> * Limit coherent and dma mask based on size retrieved from
>>> * firmware.
>>> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
>>> index 762b61f..8961b51 100644
>>> --- a/drivers/acpi/scan.c
>>> +++ b/drivers/acpi/scan.c
>>> @@ -20,6 +20,7 @@
>>> #include <linux/platform_data/x86/apple.h>
>>> #include <linux/pgtable.h>
>>> #include <linux/crc32.h>
>>> +#include <linux/dma-direct.h>
>>> #include "internal.h"
>>> @@ -1492,15 +1493,15 @@ enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
>>> *
>>> * Return 0 on success, < 0 on failure.
>>> */
>>> -int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
>>> - u64 *size)
>>> +int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map)
>>> {
>>> struct acpi_device *adev;
>>> LIST_HEAD(list);
>>> struct resource_entry *rentry;
>>> int ret;
>>> struct device *dma_dev = dev;
>>> - u64 len, dma_start = U64_MAX, dma_end = 0, dma_offset = 0;
>>> + int num_ranges = 0;
>>> + struct bus_dma_region *r;
>>> /*
>>> * Walk the device tree chasing an ACPI companion with a _DMA
>>> @@ -1525,31 +1526,31 @@ int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
>>> ret = acpi_dev_get_dma_resources(adev, &list);
>>> if (ret > 0) {
>>> + list_for_each_entry(rentry, &list, node)
>>> + num_ranges++;
>>> +
>>> + r = kcalloc(num_ranges + 1, sizeof(*r), GFP_KERNEL);
>>> + if (!r) {
>>> + ret = -ENOMEM;
>>> + goto out;
>>> + }
>>> +
>>> + *map = r;
>>> +
>>> list_for_each_entry(rentry, &list, node) {
>>> - if (dma_offset && rentry->offset != dma_offset) {
>>> + if (rentry->res->start >= rentry->res->end) {
>>> ret = -EINVAL;
>>> - dev_warn(dma_dev, "Can't handle multiple windows with different offsets\n");
>>> + dev_dbg(dma_dev, "Invalid DMA regions configuration\n");
>>> goto out;
>>> }
>>> - dma_offset = rentry->offset;
>>> -
>>> - /* Take lower and upper limits */
>>> - if (rentry->res->start < dma_start)
>>> - dma_start = rentry->res->start;
>>> - if (rentry->res->end > dma_end)
>>> - dma_end = rentry->res->end;
>>> - }
>>> - if (dma_start >= dma_end) {
>>> - ret = -EINVAL;
>>> - dev_dbg(dma_dev, "Invalid DMA regions configuration\n");
>>> - goto out;
>>> + r->cpu_start = rentry->res->start;
>>> + r->dma_start = rentry->res->start - rentry->offset;
>>> + r->size = rentry->res->end - rentry->res->start + 1;
>>> + r->offset = rentry->offset;
>>> + r++;
>>> }
>>> - *dma_addr = dma_start - dma_offset;
>>> - len = dma_end - dma_start;
>>> - *size = max(len, len + 1);
>>> - *offset = dma_offset;
>>> }
>>> out:
>>> acpi_dev_free_resource_list(&list);
>>> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
>>> index 0dc1ea0b..e106073 100644
>>> --- a/include/acpi/acpi_bus.h
>>> +++ b/include/acpi/acpi_bus.h
>>> @@ -611,8 +611,7 @@ struct acpi_pci_root {
>>> int acpi_iommu_fwspec_init(struct device *dev, u32 id,
>>> struct fwnode_handle *fwnode,
>>> const struct iommu_ops *ops);
>>> -int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
>>> - u64 *size);
>>> +int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map);
>>> int acpi_dma_configure_id(struct device *dev, enum dev_dma_attr attr,
>>> const u32 *input_id);
>>> static inline int acpi_dma_configure(struct device *dev,
>>> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
>>> index 44975c1..f806092 100644
>>> --- a/include/linux/acpi.h
>>> +++ b/include/linux/acpi.h
>>> @@ -974,8 +974,7 @@ static inline enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
>>> return DEV_DMA_NOT_SUPPORTED;
>>> }
>>> -static inline int acpi_dma_get_range(struct device *dev, u64 *dma_addr,
>>> - u64 *offset, u64 *size)
>>> +static inline int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map)
>>> {
>>> return -ENODEV;
>>> }
>>>
>>
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