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Message-ID: <d3c88451-4bf5-61f6-1a13-7176d587e36a@nvidia.com>
Date: Fri, 3 Jan 2020 15:10:39 +0530
From: Vidya Sagar <vidyas@...dia.com>
To: Kishon Vijay Abraham I <kishon@...com>, <jingoohan1@...il.com>,
<gustavo.pimentel@...opsys.com>, <lorenzo.pieralisi@....com>,
<andrew.murray@....com>, <bhelgaas@...gle.com>,
<thierry.reding@...il.com>
CC: <Jisheng.Zhang@...aptics.com>, <jonathanh@...dia.com>,
<linux-pci@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<kthota@...dia.com>, <mmaddireddy@...dia.com>, <sagar.tv@...il.com>
Subject: Re: [PATCH 4/4] PCI: pci-epf-test: Add support to defer core
initialization
On 12/5/2019 4:52 PM, Kishon Vijay Abraham I wrote:
> Hi,
>
> On 01/12/19 7:59 pm, Vidya Sagar wrote:
>> On 11/27/2019 2:50 PM, Kishon Vijay Abraham I wrote:
>>> Hi,
>>>
>>> On 13/11/19 2:38 PM, Vidya Sagar wrote:
>>>> Add support to defer core initialization and to receive a notifier
>>>> when core is ready to accommodate platforms where core is not for
>>>> initialization untile reference clock from host is available.
>>>>
>>>> Signed-off-by: Vidya Sagar <vidyas@...dia.com>
>>>> ---
>>>> drivers/pci/endpoint/functions/pci-epf-test.c | 114 ++++++++++++------
>>>> 1 file changed, 77 insertions(+), 37 deletions(-)
>>>>
>>>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>>>> index bddff15052cc..068024fab544 100644
>>>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>>>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>>>> @@ -360,18 +360,6 @@ static void pci_epf_test_cmd_handler(struct work_struct *work)
>>>> msecs_to_jiffies(1));
>>>> }
>>>> -static int pci_epf_test_notifier(struct notifier_block *nb, unsigned long val,
>>>> - void *data)
>>>> -{
>>>> - struct pci_epf *epf = container_of(nb, struct pci_epf, nb);
>>>> - struct pci_epf_test *epf_test = epf_get_drvdata(epf);
>>>> -
>>>> - queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler,
>>>> - msecs_to_jiffies(1));
>>>> -
>>>> - return NOTIFY_OK;
>>>> -}
>>>> -
>>>> static void pci_epf_test_unbind(struct pci_epf *epf)
>>>> {
>>>> struct pci_epf_test *epf_test = epf_get_drvdata(epf);
>>>> @@ -428,6 +416,78 @@ static int pci_epf_test_set_bar(struct pci_epf *epf)
>>>> return 0;
>>>> }
>>>> +static int pci_epf_test_core_init(struct pci_epf *epf)
>>>> +{
>>>> + struct pci_epf_header *header = epf->header;
>>>> + const struct pci_epc_features *epc_features;
>>>> + struct pci_epc *epc = epf->epc;
>>>> + struct device *dev = &epf->dev;
>>>> + bool msix_capable = false;
>>>> + bool msi_capable = true;
>>>> + int ret;
>>>> +
>>>> + epc_features = pci_epc_get_features(epc, epf->func_no);
>>>> + if (epc_features) {
>>>> + msix_capable = epc_features->msix_capable;
>>>> + msi_capable = epc_features->msi_capable;
>>>> + }
>>>> +
>>>> + ret = pci_epc_write_header(epc, epf->func_no, header);
>>>> + if (ret) {
>>>> + dev_err(dev, "Configuration header write failed\n");
>>>> + return ret;
>>>> + }
>>>> +
>>>> + ret = pci_epf_test_set_bar(epf);
>>>> + if (ret)
>>>> + return ret;
>>>> +
>>>> + if (msi_capable) {
>>>> + ret = pci_epc_set_msi(epc, epf->func_no, epf->msi_interrupts);
>>>> + if (ret) {
>>>> + dev_err(dev, "MSI configuration failed\n");
>>>> + return ret;
>>>> + }
>>>> + }
>>>> +
>>>> + if (msix_capable) {
>>>> + ret = pci_epc_set_msix(epc, epf->func_no, epf->msix_interrupts);
>>>> + if (ret) {
>>>> + dev_err(dev, "MSI-X configuration failed\n");
>>>> + return ret;
>>>> + }
>>>> + }
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int pci_epf_test_notifier(struct notifier_block *nb, unsigned long val,
>>>> + void *data)
>>>> +{
>>>> + struct pci_epf *epf = container_of(nb, struct pci_epf, nb);
>>>> + struct pci_epf_test *epf_test = epf_get_drvdata(epf);
>>>> + int ret;
>>>> +
>>>> + switch (val) {
>>>> + case CORE_INIT:
>>>> + ret = pci_epf_test_core_init(epf);
>>>> + if (ret)
>>>> + return NOTIFY_BAD;
>>>> + break;
>>>> +
>>>> + case LINK_UP:
>>>> + queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler,
>>>> + msecs_to_jiffies(1));
>>>> + break;
>>>> +
>>>> + default:
>>>> + dev_err(&epf->dev, "Invalid EPF test notifier event\n");
>>>> + return NOTIFY_BAD;
>>>> + }
>>>> +
>>>> + return NOTIFY_OK;
>>>> +}
>>>> +
>>>> static int pci_epf_test_alloc_space(struct pci_epf *epf)
>>>> {
>>>> struct pci_epf_test *epf_test = epf_get_drvdata(epf);
>>>> @@ -496,12 +556,11 @@ static int pci_epf_test_bind(struct pci_epf *epf)
>>>> {
>>>> int ret;
>>>> struct pci_epf_test *epf_test = epf_get_drvdata(epf);
>>>> - struct pci_epf_header *header = epf->header;
>>>> const struct pci_epc_features *epc_features;
>>>> enum pci_barno test_reg_bar = BAR_0;
>>>> struct pci_epc *epc = epf->epc;
>>>> - struct device *dev = &epf->dev;
>>>> bool linkup_notifier = false;
>>>> + bool skip_core_init = false;
>>>> bool msix_capable = false;
>>>> bool msi_capable = true;
>>>> @@ -511,6 +570,7 @@ static int pci_epf_test_bind(struct pci_epf *epf)
>>>> epc_features = pci_epc_get_features(epc, epf->func_no);
>>>> if (epc_features) {
>>>> linkup_notifier = epc_features->linkup_notifier;
>>>> + skip_core_init = epc_features->skip_core_init;
>>>> msix_capable = epc_features->msix_capable;
>>>> msi_capable = epc_features->msi_capable;
>>>
>>> Are these used anywhere in this function?
>> Nope. I'll remove them.
>>
>>>> test_reg_bar = pci_epc_get_first_free_bar(epc_features);
>>>> @@ -520,34 +580,14 @@ static int pci_epf_test_bind(struct pci_epf *epf)
>>>> epf_test->test_reg_bar = test_reg_bar;
>>>> epf_test->epc_features = epc_features;
>>>> - ret = pci_epc_write_header(epc, epf->func_no, header);
>>>> - if (ret) {
>>>> - dev_err(dev, "Configuration header write failed\n");
>>>> - return ret;
>>>> - }
>>>> -
>>>> ret = pci_epf_test_alloc_space(epf);
>>>> if (ret)
>>>> return ret;
>>>> - ret = pci_epf_test_set_bar(epf);
>>>> - if (ret)
>>>> - return ret;
>>>> -
>>>> - if (msi_capable) {
>>>> - ret = pci_epc_set_msi(epc, epf->func_no, epf->msi_interrupts);
>>>> - if (ret) {
>>>> - dev_err(dev, "MSI configuration failed\n");
>>>> - return ret;
>>>> - }
>>>> - }
>>>> -
>>>> - if (msix_capable) {
>>>> - ret = pci_epc_set_msix(epc, epf->func_no, epf->msix_interrupts);
>>>> - if (ret) {
>>>> - dev_err(dev, "MSI-X configuration failed\n");
>>>> + if (!skip_core_init) {
>>>> + ret = pci_epf_test_core_init(epf);
>>>> + if (ret)
>>>> return ret;
>>>> - }
>>>> }
>>>> if (linkup_notifier) {
>>>
>>> This could as well be moved to pci_epf_test_core_init().
>> Yes, but I would like to keep only the code that touches hardware in pci_epf_test_core_init()
>> to minimize the time it takes to execute it. Is there any strong reason to move it? if not,
>> I would prefer to leave it here in this function itself.
>
> There is no point in scheduling a work to check for commands from host when the EP itself is not initialized.
True. But, since this is more of preparatory work, I thought we should just have it done here itself.
Main reason being, once PERST is perceived, endpoint can't take too much initializing its core. So, I want to
keep that part as minimalistic as possible.
- Vidya Sagar
>
> Thanks
> Kishon
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