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Date: Thu, 9 Aug 2012 09:36:05 +0530
From: "DebBarma, Tarun Kanti" <tarun.kanti@...com>
To: Kevin Hilman <khilman@...com>
Cc: linux-omap@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, Rajendra Nayak <rnayak@...com>,
Santosh Shilimkar <santosh.shilimkar@...com>,
"Cousson, Benoit" <b-cousson@...com>,
Paul Walmsley <paul@...an.com>
Subject: Re: [PATCH v2] gpio/omap: add *remove* callback in platform_driver
On Wed, Aug 8, 2012 at 10:40 PM, Kevin Hilman <khilman@...com> wrote:
> Tarun Kanti DebBarma <tarun.kanti@...com> writes:
>
>> Add *remove* callback so that necessary cleanup operations are
>> performed when device is unregistered. The device is deleted
>> from the list and associated clock handle is released by
>> calling clk_put() and irq descriptor is released using the
>> irq_free_desc() api.
>>
>> Signed-off-by: Tarun Kanti DebBarma <tarun.kanti@...com>
>> Reported-by: Paul Walmsley <paul@...an.com>
>> Reviewed-by: Jon Hunter <jon-hunter@...com>
>> Cc: Kevin Hilman <khilman@...com>
>> Cc: Rajendra Nayak <rnayak@...com>
>> Cc: Santosh Shilimkar <santosh.shilimkar@...com>
>> Cc: Cousson, Benoit <b-cousson@...com>
>> Cc: Paul Walmsley <paul@...an.com>
>> ---
>> v2:
>> Baseline: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
>> Commit: 0d7614f09c1ebdbaa1599a5aba7593f147bf96ee (Linux 3.6-rc1)
>>
>> (1) Use irq_free_descs() instead of irq_free_desc().
>> Besides, irq_free_desc() was using wrong parameter,
>> irq_base, instead of bank->irq.
>> (2) irq_free_descs() moved outside spin_lock/unlock_*()
>> in order to avoid exception warnings.
>>
>> (3) pm_runtime_disable() added so that bind can happen successfully
>>
>> Test Detail:
>> Step 1: Unbind gpio.5 device in order to invoke the *remove* callback.
>> #echo "omap_gpio.5" > sys/bus/platform/drivers/omap_gpio/unbind
>>
>> Step 2: Bind gpio.5 device and confirm probe() for the device succeeds.
>> #echo "omap_gpio.5" > sys/bus/platform/drivers/omap_gpio/bind
>>
>> Step 3: Execute read/write GPIO test case.
>
> What happens when GPIOs are in use (requested)?
If I try to unbind a currently active GPIO bank then I see an exception
after the irq descriptor is freed by the remove. I believe this is expected
because interrupt raised by the system would not be handled.
[ 18.859405] irq_free_descs: calling free_desc(192)...
[ 18.866180] irq_free_descs: calling free_desc(192)...
[ 18.872680] irq_free_descs: calling free_desc(192)...
[ 18.877990] irq_free_descs: calling free_desc(192)...
[ 18.883270] irq_free_descs: calling free_desc(192)...
[ 18.888549] irq_free_descs: calling free_desc(192)...
[ 18.893859] irq_free_descs: calling free_desc(192)...
[ 18.899139] irq_free_descs: calling free_desc(192)...
[ 18.904418] irq_free_descs: calling free_desc(192)...
[ 18.909729] irq_free_descs: calling free_desc(192)...
[ 18.915008] irq_free_descs: calling free_desc(192)...
[ 18.920288] irq_free_descs: calling free_desc(192)...
[ 18.925598] irq_free_descs: calling free_desc(192)...
[ 18.930877] irq_free_descs: calling free_desc(192)...
[ 18.936157] irq_free_descs: calling free_desc(192)...
[ 18.941467] irq_free_descs: calling free_desc(192)...
[ 18.946746] irq_free_descs: calling free_desc(192)...
[ 18.952026] irq_free_descs: calling free_desc(192)...
[ 18.957336] irq_free_descs: calling free_desc(192)...
[ 18.962615] irq_free_descs: calling free_desc(192)...
[ 18.967895] irq_free_descs: calling free_desc(192)...
[ 18.973205] irq_free_descs: calling free_desc(192)...
[ 18.978485] irq_free_descs: calling free_desc(192)...
[ 18.983764] irq_free_descs: calling free_desc(192)...
[ 18.989074] irq_free_descs: calling free_desc(192)...
[ 18.994354] irq_free_descs: calling free_desc(192)...
[ 18.999633] irq_free_descs: calling free_desc(192)...
[ 19.004913] irq_free_descs: calling free_desc(192)...
[ 19.010223] irq_free_descs: calling free_desc(192)...
[ 19.015502] irq_free_descs: calling free_desc(192)...
[ 19.020782] irq_free_descs: calling free_desc(192)...
[ 19.026092] irq_free_descs: calling free_desc(192)...
[ 19.032440] irq 194, desc: c072f340, depth: 1, count: 0, unhandled: 0
[ 19.039154] ->handle_irq(): c00a3e08, handle_bad_irq+0x0/0x260
[ 19.045379] ->irq_data.chip(): c078ff7c, no_irq_chip+0x0/0x5c
[ 19.051391] ->action(): ef0d42c0
[ 19.054748] ->action->handler(): c0399ee0, ks8851_irq+0x0/0x1c
[ 19.060852] IRQ_NOPROBE set
[ 19.064056] IRQ_NOREQUEST set
[ 19.067230] Unable to handle kernel paging request at virtual address 203a6c9
[ 19.074768] pgd = c0004000
[ 19.077606] [203a6c99] *pgd=00000000
[ 19.081329] Internal error: Oops: 5 [#1] SMP ARM
[ 19.086151] Modules linked in:
[ 19.089355] CPU: 0 Not tainted (3.6.0-rc1-00003-g43a916d-dirty #885)
[ 19.096374] PC is at gpio_irq_handler+0x7c/0x26c
[ 19.101165] LR is at handle_bad_irq+0x1cc/0x260
[ 19.105895] pc : [<c02e13b0>] lr : [<c00a3fd4>] psr: 60000093
[ 19.105895] sp : c0725df8 ip : 00006fc6 fp : 00000001
[ 19.117889] r10: 00000000 r9 : fa05502c r8 : 00000020
[ 19.123352] r7 : 00000000 r6 : 00000000 r5 : 00000000 r4 : ef0bbe10
[ 19.130157] r3 : ef0c1980 r2 : 203a6c65 r1 : 00000034 r0 : 00000000
[ 19.136993] Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kel
[ 19.144714] Control: 10c53c7d Table: ae89804a DAC: 00000017
[ 19.150695] Process swapper/0 (pid: 0, stack limit = 0xc07242f8)
[ 19.156982] Stack: (0xc0725df8 to 0xc0726000)
[ 19.161529] 5de0: c0740
[ 19.170074] 5e00: c0724000 c0724000 c07440d8 c07224a4 0000003e 00000000 c0740
[ 19.178619] 5e20: c0725edc c00a3670 000001da c0015380 fa24010c c0742d30 c0720
[ 19.187164] 5e40: 00000001 c000846c c0746980 c04f8c74 20000013 ffffffff c0724
[ 19.195709] 5e60: 0005ebb2 00000001 00000000 c0746980 c1530ac0 ee8cfe00 c1530
[ 19.204223] 5e80: 00000001 c07440d8 ee8cfe00 c0725edc 00000001 c0725ea8 00054
[ 19.212768] 5ea0: 20000013 ffffffff c0724000 c007425c 00000002 00000000 c0077
[ 19.221313] 5ec0: ef320b00 c0746980 00000000 c1530ac0 ef320b00 c0722ac0 c0720
[ 19.229858] 5ee0: c152ec20 c00696cc 00000000 00000000 c0724000 c0724000 c1524
[ 19.238403] 5f00: c152ec20 c0015e14 c0722ac0 c0722ac0 c0722ac0 c0722ac0 c0720
[ 19.246948] 5f20: c0722ac0 c0722ac0 6e6b0f0d 00000004 00000000 00000000 c0080
[ 19.255493] 5f40: 00000001 00000000 00000000 501539bc 00000004 c0091654 c1528
[ 19.264038] 5f60: c07d55b8 5006c071 00000000 c008cab8 00000000 00000002 50064
[ 19.272552] 5f80: c0748078 c0724000 c07c0548 c0504510 c0747e60 00000000 411f8
[ 19.281097] 5fa0: 00000000 c0015e14 00000000 c0743e1c c07c0480 c07057dc bfffa
[ 19.289642] 5fc0: 00000000 c06d48d8 ffffffff ffffffff c06d4450 00000000 0000c
[ 19.298187] 5fe0: 00000000 10c53c7d c0742d08 c07057ac c0747e54 80008044 00000
[ 19.306732] [<c02e13b0>] (gpio_irq_handler+0x7c/0x26c) from [<c00a3670>] (ge)
[ 19.316558] [<c00a3670>] (generic_handle_irq+0x34/0x44) from [<c0015380>] (h)
[ 19.325744] [<c0015380>] (handle_IRQ+0x4c/0xac) from [<c000846c>] (gic_handl)
[ 19.334564] [<c000846c>] (gic_handle_irq+0x2c/0x60) from [<c04f8ee4>] (__irq)
[ 19.343292] Exception stack(0xc0725e60 to 0xc0725ea8)
[ 19.348571] 5e60: 0005ebb2 00000001 00000000 c0746980 c1530ac0 ee8cfe00 c1530
[ 19.357116] 5e80: 00000001 c07440d8 ee8cfe00 c0725edc 00000001 c0725ea8 00054
[ 19.365631] 5ea0: 20000013 ffffffff
[ 19.369293] [<c04f8ee4>] (__irq_svc+0x44/0x5c) from [<c04f8c74>] (_raw_spin_)
[ 19.378570] [<c04f8c74>] (_raw_spin_unlock_irq+0x28/0x2c) from [<c007425c>] )
[ 19.388732] [<c007425c>] (finish_task_switch+0x84/0x198) from [<c04f7760>] ()
[ 19.398193] [<c04f7760>] (__schedule+0x404/0x870) from [<c0015e14>] (cpu_idl)
[ 19.406768] [<c0015e14>] (cpu_idle+0xe8/0x114) from [<c06d48d8>] (start_kern)
[ 19.415466] Code: e59480e4 e1d311b4 e5d36034 e1a0a81b (e7920001)
[ 19.421844] ---[ end trace 3eb9bf4b81babe15 ]---
[ 19.426666] Kernel panic - not syncing: Fatal exception in interrupt
[ 19.433288] CPU1: stopping
[ 19.436157] [<c001beac>] (unwind_backtrace+0x0/0xf4) from [<c0019db4>] (hand)
[ 19.445220] [<c0019db4>] (handle_IPI+0x130/0x15c) from [<c0008498>] (gic_han)
[ 19.454223] [<c0008498>] (gic_handle_irq+0x58/0x60) from [<c04f8ee4>] (__irq)
[ 19.462951] Exception stack(0xef06ff88 to 0xef06ffd0)
[ 19.468231] ff80: c079f960 c079f960 00000000 00000000 ef068
[ 19.476745] ffa0: c0504510 c0747e60 00000000 411fc092 c0748078 00000000 00000
[ 19.485290] ffc0: c0015570 c0015574 60000113 ffffffff
[ 19.490570] [<c04f8ee4>] (__irq_svc+0x44/0x5c) from [<c0015574>] (default_id)
[ 19.499114] [<c0015574>] (default_idle+0x20/0x44) from [<c0015dc8>] (cpu_idl)
[ 19.507659] [<c0015dc8>] (cpu_idle+0x9c/0x114) from [<804f1d94>] (0x804f1d94)
---
Tarun
>
> Kevin
>
>> drivers/gpio/gpio-omap.c | 35 +++++++++++++++++++++++++++++++++++
>> 1 files changed, 35 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
>> index e6efd77..50de875 100644
>> --- a/drivers/gpio/gpio-omap.c
>> +++ b/drivers/gpio/gpio-omap.c
>> @@ -1152,6 +1152,40 @@ static int __devinit omap_gpio_probe(struct platform_device *pdev)
>> return ret;
>> }
>>
>> +/**
>> + * omap_gpio_remove - cleanup a registered gpio device
>> + * @pdev: pointer to current gpio platform device
>> + *
>> + * Called by driver framework whenever a gpio device is unregistered.
>> + * GPIO is deleted from the list and associated clock handle freed.
>> + */
>> +static int __devexit omap_gpio_remove(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct gpio_bank *bank;
>> + unsigned long flags;
>> + int ret = -EINVAL;
>> +
>> + list_for_each_entry(bank, &omap_gpio_list, node) {
>> + spin_lock_irqsave(&bank->lock, flags);
>> + if (bank->dev == dev) {
>> + clk_put(bank->dbck);
>> + list_del(&bank->node);
>> + ret = 0;
>> + spin_unlock_irqrestore(&bank->lock, flags);
>> + break;
>> + }
>> + spin_unlock_irqrestore(&bank->lock, flags);
>> + }
>> +
>> + if (!ret) {
>> + pm_runtime_disable(bank->dev);
>> + irq_free_descs(bank->irq_base, bank->width);
>> + }
>> +
>> + return ret;
>> +}
>> +
>> #ifdef CONFIG_ARCH_OMAP2PLUS
>>
>> #if defined(CONFIG_PM_RUNTIME)
>> @@ -1478,6 +1512,7 @@ MODULE_DEVICE_TABLE(of, omap_gpio_match);
>>
>> static struct platform_driver omap_gpio_driver = {
>> .probe = omap_gpio_probe,
>> + .remove = __devexit_p(omap_gpio_remove),
>> .driver = {
>> .name = "omap_gpio",
>> .pm = &gpio_pm_ops,
--
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