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@linaro.org>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
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);
+ /* Don't use devm_ioremap_resource, as we're accessing a shared region. */
+ priv->base = devm_ioremap(dev, res.start, resource_size(&res));
+ of_node_put(msgram_np);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+ } else {
+ /* Otherwise, fall back to simple MMIO. */
+ priv->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+ }
for (i = 0; i < priv->reg_stride; i++) {
qcom_mpm_write(priv, MPM_REG_ENABLE, i, 0);
--
2.43.0On 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@linaro.org>
> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
> ---
> 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.
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.
Once fixed.
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
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@linaro.org>
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
>> ---
>> 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
© 2016 - 2025 Red Hat, Inc.