From: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
To: Daniel Axtens <dja@axtens.net>, mpe@ellerman.id.au
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
ego@linux.vnet.ibm.com, bsingharora@gmail.com,
benh@kernel.crashing.org, paulus@samba.org, anton@samba.org,
sukadev@linux.vnet.ibm.com, mikey@neuling.org,
stewart@linux.vnet.ibm.com, eranian@google.com,
Hemant Kumar <hemant@linux.vnet.ibm.com>,
Anju T Sudhakar <anju@linux.vnet.ibm.com>
Subject: Re: [PATCH v6 02/11] powerpc/powernv: Autoload IMC device driver module
Date: Wed, 5 Apr 2017 12:04:20 +0530 [thread overview]
Message-ID: <a5ffa4ae-35aa-2149-b0e7-3b7604f7a17a@linux.vnet.ibm.com> (raw)
In-Reply-To: <87pogtkmyf.fsf@possimpible.ozlabs.ibm.com>
On Tuesday 04 April 2017 06:28 AM, Daniel Axtens wrote:
> Hi all,
>
> I'm trying to get my head around these patches - at this point I'm just
> doing a first pass, so I may have more substantive structural comments
> later on. In the mean time - here are some minor C nits:
>
>> + * Copyright (C) 2016 Madhavan Srinivasan, IBM Corporation.
>> + * (C) 2016 Hemant K Shaw, IBM Corporation.
> Should these be bumped to 2017?
Facepalm. my bad. Will fix it.
>> +
>> + do {
>> + pages = PAGE_SIZE * i;
>> + pcni->vbase[i++] = (u64)phys_to_virt(pcni->pbase +
>> + pages);
>> + } while (i < (pcni->size / PAGE_SIZE));
>> + }
> I had to scroll back up to the top of this function to make sure I
> understood what this loop does. Would it be better to write it as:
>
> for (i = 0; i < (pcni->size / PAGE_SIZE); i++) {
> pages = PAGE_SIZE * i;
> pcni->vbase[i] = (u64)....
> }
Idea is to map all of the nest counter area since event
offset could be anywhere within this region.
Will document that here.
>
> And, just checking - this is expected to work on both 4 and 64kB pages?
Yes. thats the intended. That said, i need to fix the
IMC_NEST_MAX_PAGES value for 4K page size.
Reason being, there was a recent change in the
size of memory allocated for nest counters in the
HOMER region for the microcode.
>
>> +
>> + return 0;
>> +err:
>> + return -ENODEV;
> You're not releasing any resources here - would it be better to just
> replace the gotos with this return? I haven't checked to see if you
> change the function later on to allocate memory - if so please ignore :)
We check in multiple places in the function and return on fail.
Thats why we made it as a generic return with goto.
>> +}
>> +
>> +static const struct of_device_id opal_imc_match[] = {
>> + { .compatible = IMC_DTB_COMPAT },
>> + {},
>> +};
>> +
>> +static struct platform_driver opal_imc_driver = {
>> + .driver = {
>> + .name = "opal-imc-counters",
>> + .of_match_table = opal_imc_match,
>> + },
>> + .probe = opal_imc_counters_probe,
>> +};
>> +
>> +MODULE_DEVICE_TABLE(of, opal_imc_match);
>> +module_platform_driver(opal_imc_driver);
>> +MODULE_DESCRIPTION("PowerNV OPAL IMC driver");
>> +MODULE_LICENSE("GPL");
>> diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
>> index e0f856bfbfe8..85ea1296f030 100644
>> --- a/arch/powerpc/platforms/powernv/opal.c
>> +++ b/arch/powerpc/platforms/powernv/opal.c
>> @@ -14,6 +14,7 @@
>> #include <linux/printk.h>
>> #include <linux/types.h>
>> #include <linux/of.h>
>> +#include <linux/of_address.h>
>> #include <linux/of_fdt.h>
>> #include <linux/of_platform.h>
>> #include <linux/interrupt.h>
>> @@ -30,6 +31,7 @@
>> #include <asm/opal.h>
>> #include <asm/firmware.h>
>> #include <asm/mce.h>
>> +#include <asm/imc-pmu.h>
>>
>> #include "powernv.h"
>>
>> @@ -631,6 +633,15 @@ static void opal_pdev_init(const char *compatible)
>> of_platform_device_create(np, NULL, NULL);
>> }
>>
>> +static void opal_imc_init_dev(void)
>> +{
>> + struct device_node *np;
>> +
>> + np = of_find_compatible_node(NULL, NULL, IMC_DTB_COMPAT);
>> + if (np)
>> + of_platform_device_create(np, NULL, NULL);
>> +}
> Should this function be tagged __init?
Yes. Thats right. Will make the changes.
Thanks for review
Maddy
>
>> +
>> static int kopald(void *unused)
>> {
>> unsigned long timeout = msecs_to_jiffies(opal_heartbeat) + 1;
>> @@ -704,6 +715,9 @@ static int __init opal_init(void)
>> /* Setup a heatbeat thread if requested by OPAL */
>> opal_init_heartbeat();
>>
>> + /* Detect IMC pmu counters support and create PMUs */
>> + opal_imc_init_dev();
>> +
>> /* Create leds platform devices */
>> leds = of_find_node_by_path("/ibm,opal/leds");
>> if (leds) {
>> --
>> 2.7.4
next prev parent reply other threads:[~2017-04-05 6:35 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-03 14:54 [PATCH v6 00/11] IMC Instrumentation Support Madhavan Srinivasan
2017-04-03 14:54 ` [PATCH v6 01/11] powerpc/powernv: Data structure and macros definitions Madhavan Srinivasan
2017-04-04 1:48 ` Daniel Axtens
2017-04-05 4:22 ` Madhavan Srinivasan
2017-04-06 8:07 ` Stewart Smith
2017-04-06 8:39 ` Stewart Smith
2017-04-03 14:54 ` [PATCH v6 02/11] powerpc/powernv: Autoload IMC device driver module Madhavan Srinivasan
2017-04-04 0:58 ` Daniel Axtens
2017-04-05 6:34 ` Madhavan Srinivasan [this message]
2017-04-04 1:48 ` Daniel Axtens
2017-04-05 6:36 ` Madhavan Srinivasan
2017-04-06 7:04 ` Stewart Smith
2017-04-03 14:55 ` [PATCH v6 03/11] powerpc/powernv: Detect supported IMC units and its events Madhavan Srinivasan
2017-04-04 1:41 ` Daniel Axtens
2017-04-05 12:29 ` Madhavan Srinivasan
2017-04-06 8:37 ` Stewart Smith
2017-04-06 9:33 ` Anju T Sudhakar
2017-04-13 11:43 ` Michael Ellerman
2017-04-17 8:08 ` Anju T Sudhakar
2017-04-03 14:55 ` [PATCH v6 04/11] powerpc/perf: Add event attribute and group to IMC pmus Madhavan Srinivasan
2017-04-04 2:11 ` Daniel Axtens
2017-04-06 6:43 ` Madhavan Srinivasan
2017-04-03 14:55 ` [PATCH v6 05/11] powerpc/perf: Generic imc pmu event functions Madhavan Srinivasan
2017-04-04 3:55 ` Daniel Axtens
2017-04-03 14:55 ` [PATCH v6 06/11] powerpc/perf: IMC pmu cpumask and cpu hotplug support Madhavan Srinivasan
2017-04-04 4:33 ` Daniel Axtens
2017-04-06 8:04 ` Madhavan Srinivasan
2017-04-03 14:55 ` [PATCH v6 07/11] powerpc/powernv: Core IMC events detection Madhavan Srinivasan
2017-04-03 14:55 ` [PATCH v6 08/11] powerpc/perf: PMU functions for Core IMC and hotplugging Madhavan Srinivasan
2017-04-03 14:55 ` [PATCH v6 09/11] powerpc/powernv: Thread IMC events detection Madhavan Srinivasan
2017-04-03 14:55 ` [PATCH v6 10/11] powerpc/perf: Thread IMC PMU functions Madhavan Srinivasan
2017-04-03 14:55 ` [PATCH v6 11/11] powerpc/perf: Thread imc cpuhotplug support Madhavan Srinivasan
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