Re: [PATCH V2 2/3] dmaengine: qcom_hidma: add support for the new revision

Robin Murphy
2017-11-08T17:51:07Z

On 08/11/17 16:29, Sinan Kaya wrote:
> Add support for probing the newer HW and also organize MSI capable hardware
> into an array for maintenance reasons.
>
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
> drivers/dma/qcom/hidma.c | 41 +++++++++++++++++++++++++++++------------
> 1 file changed, 29 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/dma/qcom/hidma.c b/drivers/dma/qcom/hidma.c
> index e366985..4ef7d6f 100644
> --- a/drivers/dma/qcom/hidma.c
> +++ b/drivers/dma/qcom/hidma.c
> @@ -50,6 +50,7 @@
> #include <linux/slab.h>
> #include <linux/spinlock.h>
> #include <linux/of_dma.h>
> +#include <linux/of_device.h>
> #include <linux/property.h>
> #include <linux/delay.h>
> #include <linux/acpi.h>
> @@ -104,6 +105,26 @@ static void hidma_free(struct hidma_dev *dmadev)
> module_param(nr_desc_prm, uint, 0644);
> MODULE_PARM_DESC(nr_desc_prm, "number of descriptors (default: 0)");
>
> +#define HIDMA_MAX_DEV_MATCH 10
> +
> +struct hidma_cap {
> + const struct of_device_id of[HIDMA_MAX_DEV_MATCH];
> + const struct acpi_device_id acpi[HIDMA_MAX_DEV_MATCH];
> +};
> +
> +static struct hidma_cap hidma_msi_cap = {
> + .of = {
> + {.compatible = "qcom,hidma-1.1",},
> + {.compatible = "qcom,hidma-1.2",},
> + {},
> + },
> +
> + .acpi = {
> + {"QCOM8062"},
> + {"QCOM8063"},
> + {},
> + }
> +};

Yikes, I dread to imagine where this is going...

Apologies if I wasn't very clear, but what I meant to imply by dropping
the of_device_get_match_data() hint was to follow one of the common
patterns where you either just have some version token:

enum foo_ver {
FOO_V1,
...
}

struct acpi_device_id foo_acpi_ids[] = {
{ "_FOO0001", FOO_V1 },
...
}

struct of_device_id foo_of_match[] = {
{ .compatible = "foo,v1", .data = (void *)FOO_V1 },
...
}

int foo_probe(struct device *dev) {
...
foodev->version = (enum foo_ver)
of_device_get_match_data(&dev->of_node)
...
}

int foo_reset(struct foodev *foodev) {
if (foodev->version == FOO_V1)
writel(0, foodev->base + 0x20);
else
writel(0, foodev->base + 0x30);
}

or if it fits the code better, encapsulate the relevant details directly:

struct foodata {
.offset = 0x20,
} foo_v1_data;

struct acpi_device_id foo_acpi_ids[] = {
{ "_FOO0001", (unsigned long)&foo_v1_data },
...
}

struct of_device_id foo_of_match[] = {
{ .compatible = "foo,v1", .data = &foo_v1_data },
...
}

int foo_probe(struct device *dev) {
...
foodev->data = of_device_get_match_data(dev->of_node)
...
}

int foo_reset(struct foodev *foodev) {
writel(0, foodev->base + foodev->data->offset);
}

Creating multiple sets of match tables seems completely backwards, and
frankly looks worse than the open-coded strcmps IMO.

Robin.

>
> /* process completed descriptors */
> static void hidma_process_completed(struct hidma_chan *mchan)
> @@ -739,22 +760,16 @@ static int hidma_request_msi(struct hidma_dev *dmadev,
> static bool hidma_msi_capable(struct device *dev)
> {
> struct acpi_device *adev = ACPI_COMPANION(dev);
> - const char *of_compat;
> - int ret = -EINVAL;
> -
> - if (!adev || acpi_disabled) {
> - ret = device_property_read_string(dev, "compatible",
> - &of_compat);
> - if (ret)
> - return false;
> + int ret;
>
> - ret = strcmp(of_compat, "qcom,hidma-1.1");
> - } else {
> + if (!adev || acpi_disabled)
> + ret = of_match_device(hidma_msi_cap.of, dev) != NULL;
> + else {
> #ifdef CONFIG_ACPI
> - ret = strcmp(acpi_device_hid(adev), "QCOM8062");
> + ret = acpi_match_device(hidma_msi_cap.acpi, dev) != NULL;
> #endif
> }
> - return ret == 0;
> + return ret;
> }
>
> static int hidma_probe(struct platform_device *pdev)
> @@ -954,6 +969,7 @@ static int hidma_remove(struct platform_device *pdev)
> static const struct acpi_device_id hidma_acpi_ids[] = {
> {"QCOM8061"},
> {"QCOM8062"},
> + {"QCOM8063"},
> {},
> };
> MODULE_DEVICE_TABLE(acpi, hidma_acpi_ids);
> @@ -962,6 +978,7 @@ static int hidma_remove(struct platform_device *pdev)
> static const struct of_device_id hidma_match[] = {
> {.compatible = "qcom,hidma-1.0",},
> {.compatible = "qcom,hidma-1.1",},
> + {.compatible = "qcom,hidma-1.2",},
> {},
> };
> MODULE_DEVICE_TABLE(of, hidma_match);
>