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Message-ID: <b33fddb8-b5de-a4dc-3795-bfb3ebf44319@quicinc.com>
Date: Thu, 13 Jul 2023 14:00:37 +0530
From: Souradeep Chowdhury <quic_schowdhu@...cinc.com>
To: Bhupesh Sharma <bhupesh.sharma@...aro.org>
CC: <linux-arm-msm@...r.kernel.org>, <linux-usb@...r.kernel.org>,
Andy Gross <agross@...nel.org>,
Konrad Dybcio <konrad.dybcio@...ainline.org>,
"Bjorn Andersson" <andersson@...nel.org>,
<gregkh@...uxfoundation.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>,
"Sibi Sankar" <quic_sibis@...cinc.com>,
Rajendra Nayak <quic_rjendra@...cinc.com>
Subject: Re: [PATCH V1 2/3] usb: misc: Add notifier call chain to Embedded USB
Debug(EUD) driver
On 7/12/2023 11:52 PM, Bhupesh Sharma wrote:
> Hi Souradeep,
>
> On Wed, 12 Jul 2023 at 13:58, Souradeep Chowdhury
> <quic_schowdhu@...cinc.com> wrote:
>>
>> Add the notifier call chain to EUD driver. The notifier call chain
>> is added to check the role-switch status of EUD. When multiple
>> modules are switching roles on the same port, they need to call this
>> notifier to check the role-switch status of EUD. If EUD is disabled,
>> then the modules can go for the role-switch, otherwise it needs to
>> be blocked. The notifier chain can be used to link multiple modules
>> switching roles on the same port and create a ordering, priority and
>> conflict resolution among them. The wrapper functions are defined here
>> which can be used to register a notifier block to the chain, deregister
>> it and also call the chain.
>>
>> Signed-off-by: Souradeep Chowdhury <quic_schowdhu@...cinc.com>
>> ---
>> drivers/usb/misc/qcom_eud.c | 52 +++++++++++++++++++++++++++++++++++--
>> 1 file changed, 50 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
>> index 7f371ea1248c..e6c97a2cf2df 100644
>> --- a/drivers/usb/misc/qcom_eud.c
>> +++ b/drivers/usb/misc/qcom_eud.c
>> @@ -11,10 +11,13 @@
>> #include <linux/kernel.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/slab.h>
>> #include <linux/sysfs.h>
>> #include <linux/usb/role.h>
>> +#include "qcom_eud_notifier.h"
>>
>> #define EUD_REG_INT1_EN_MASK 0x0024
>> #define EUD_REG_INT_STATUS_1 0x0044
>> @@ -22,14 +25,16 @@
>> #define EUD_REG_VBUS_INT_CLR 0x0080
>> #define EUD_REG_CSR_EUD_EN 0x1014
>> #define EUD_REG_SW_ATTACH_DET 0x1018
>> -#define EUD_REG_EUD_EN2 0x0000
>> +#define EUD_REG_EUD_EN2 0x0000
>>
>> #define EUD_ENABLE BIT(0)
>> -#define EUD_INT_PET_EUD BIT(0)
>
> These indentation issues are already addressed in my EUD patches.
> Please rebase your patches on the same to reuse those
Ack
>
>> +#define EUD_INT_PET_EUD BIT(0)
>> #define EUD_INT_VBUS BIT(2)
>> #define EUD_INT_SAFE_MODE BIT(4)
>> #define EUD_INT_ALL (EUD_INT_VBUS | EUD_INT_SAFE_MODE)
>>
>> +static RAW_NOTIFIER_HEAD(eud_nh);
>> +
>> struct eud_chip {
>> struct device *dev;
>> struct usb_role_switch *role_sw;
>> @@ -41,6 +46,42 @@ struct eud_chip {
>> bool usb_attached;
>> };
>>
>> +int eud_register_notify(struct notifier_block *nb)
>> +{
>> + return raw_notifier_chain_register(&eud_nh, nb);
>> +}
>> +EXPORT_SYMBOL_GPL(eud_register_notify);
>> +
>> +void eud_unregister_notify(struct notifier_block *nb)
>> +{
>> + raw_notifier_chain_unregister(&eud_nh, nb);
>> +}
>> +EXPORT_SYMBOL_GPL(eud_unregister_notify);
>> +
>> +void eud_notifier_call_chain(unsigned long role_switch_state)
>> +{
>> + raw_notifier_call_chain(&eud_nh, role_switch_state, NULL);
>> +}
>> +EXPORT_SYMBOL_GPL(eud_notifier_call_chain);
>
> Probably I missed it, but you have not provided any example users of
> these APIs in the patchset or reference to another one which shows how
> these APIs are used.
Ack, the usage for this will be posted in the next version.
>
>> +static int eud_vbus_spoof_attach_detach(struct notifier_block *nb, unsigned long event,
>> + void *data)
>> +{
>> + struct device_node *eud = of_find_compatible_node(NULL, NULL, "qcom,eud");
>> + struct device *eud_device = bus_find_device_by_of_node(&platform_bus_type, eud);
>> + struct eud_chip *eud_data = dev_get_drvdata(eud_device);
>> +
>> + if (eud_data->enabled && event != USB_ROLE_DEVICE)
>> + return NOTIFY_BAD;
>> + else
>> + return NOTIFY_OK;
>> +}
>> +
>> +static struct notifier_block eud_notifier = {
>> + .notifier_call = eud_vbus_spoof_attach_detach,
>> + .priority = 1,
>
> Why do you need a 'priority = 1' here, it can be 0 or even lower?
Priority is 0 by default for a notifier block, since eud notifier
needs to be the first to be called in the chain to check the
role-switch status, I have kept the priority as 1 here.
>
> Thanks,
> Bhupesh
>
>> +};
>> +
>> static int enable_eud(struct eud_chip *priv)
>> {
>> writel(EUD_ENABLE, priv->base + EUD_REG_CSR_EUD_EN);
>> @@ -196,6 +237,10 @@ static int eud_probe(struct platform_device *pdev)
>> return dev_err_probe(chip->dev, ret,
>> "failed to add role switch release action\n");
>>
>> + ret = eud_register_notify(&eud_notifier);
>> + if (ret)
>> + return dev_err_probe(chip->dev, ret, "failed to register notifier\n");
>> +
>> chip->base = devm_platform_ioremap_resource(pdev, 0);
>> if (IS_ERR(chip->base))
>> return PTR_ERR(chip->base);
>> @@ -226,6 +271,9 @@ static void eud_remove(struct platform_device *pdev)
>>
>> device_init_wakeup(&pdev->dev, false);
>> disable_irq_wake(chip->irq);
>> + eud_unregister_notify(&eud_notifier);
>> +
>> + return 0;
>> }
>>
>> static const struct of_device_id eud_dt_match[] = {
>> --
>> 2.17.1
>>
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