On 25.11.2023 16:17, Bryan O'Donoghue wrote:
> On 25/11/2023 14:27, Konrad Dybcio wrote:
>> The MPM hardware is accessible to us from the ARM CPUs through a shared
>> memory region (RPM MSG RAM) that's also concurrently accessed by other
>> kinds of cores on the system (like modem, ADSP etc.). Modeling this
>> relation in a (somewhat) sane manner in the device tree basically
>> requires us to either present the MPM as a child of said memory region
>> (which makes little sense, as a mapped memory carveout is not a bus),
>> define nodes which bleed their register spaces into one another, or
>> passing their slice of the MSG RAM through some kind of a property.
>>
>> Go with the third option and add a way to map a region passed through
>> the "qcom,rpm-msg-ram" property as our register space.
>>
>> The current way of using 'reg' is preserved for ABI reasons.
>>
>> Acked-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
>> ---
>> drivers/irqchip/irq-qcom-mpm.c | 21 ++++++++++++++++++---
>> 1 file changed, 18 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/irqchip/irq-qcom-mpm.c b/drivers/irqchip/irq-qcom-mpm.c
>> index 7124565234a5..7115e3056aa5 100644
>> --- a/drivers/irqchip/irq-qcom-mpm.c
>> +++ b/drivers/irqchip/irq-qcom-mpm.c
>> @@ -14,6 +14,7 @@
>> #include <linux/mailbox_client.h>
>> #include <linux/module.h>
>> #include <linux/of.h>
>> +#include <linux/of_address.h>
>> #include <linux/of_platform.h>
>> #include <linux/platform_device.h>
>> #include <linux/pm_domain.h>
>> @@ -322,8 +323,10 @@ static int qcom_mpm_init(struct device_node *np, struct device_node *parent)
>> struct device *dev = &pdev->dev;
>> struct irq_domain *parent_domain;
>> struct generic_pm_domain *genpd;
>> + struct device_node *msgram_np;
>> struct qcom_mpm_priv *priv;
>> unsigned int pin_cnt;
>> + struct resource res;
>> int i, irq;
>> int ret;
>> @@ -374,9 +377,21 @@ static int qcom_mpm_init(struct device_node *np, struct device_node *parent)
>> raw_spin_lock_init(&priv->lock);
>> - priv->base = devm_platform_ioremap_resource(pdev, 0);
>> - if (IS_ERR(priv->base))
>> - return PTR_ERR(priv->base);
>> + /* If we have a handle to an RPM message ram partition, use it. */
>> + msgram_np = of_parse_phandle(np, "qcom,rpm-msg-ram", 0);
>> + if (msgram_np) {
>> + ret = of_address_to_resource(msgram_np, 0, &res);
>
> You are capturing the return value but doing nothing with it.
Oops you're right
>
> One of
>
> if (ret) {
> of_node_put(msgram_np);
> return ret;
> }
>
> or just drop the ret =
>
> if you are sure of_address_to_resource() can never return an error for your use-case.
Never say never!
Konrad
