diff mbox

[2/3] ath10k: always save/restore pci config space

Message ID 1425287344-30594-2-git-send-email-michal.kazior@tieto.com (mailing list archive)
State Not Applicable
Delegated to: Kalle Valo
Headers show

Commit Message

Michal Kazior March 2, 2015, 9:09 a.m. UTC
The check isn't really necessary and couldn't even
work because becase pci_restore_state() restores
only first 64 bytes of PCI configuration space.

This is necessary for future WoWLAN support.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
---
 drivers/net/wireless/ath/ath10k/pci.c | 37 +++++++++++------------------------
 1 file changed, 11 insertions(+), 26 deletions(-)

Comments

Johannes Berg March 2, 2015, 9:16 a.m. UTC | #1
On Mon, 2015-03-02 at 10:09 +0100, Michal Kazior wrote:
> The check isn't really necessary and couldn't even
> work because becase pci_restore_state() restores
> only first 64 bytes of PCI configuration space.
> 
> This is necessary for future WoWLAN support.

> +	pci_save_state(pdev);
> +	pci_disable_device(pdev);

I believe the whole thing isn't necessary at all since the kernel's PCIe
layer will take care of it.

johannes

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Michal Kazior March 2, 2015, 9:23 a.m. UTC | #2
On 2 March 2015 at 10:16, Johannes Berg <johannes@sipsolutions.net> wrote:
> On Mon, 2015-03-02 at 10:09 +0100, Michal Kazior wrote:
>> The check isn't really necessary and couldn't even
>> work because becase pci_restore_state() restores
>> only first 64 bytes of PCI configuration space.
>>
>> This is necessary for future WoWLAN support.
>
>> +     pci_save_state(pdev);
>> +     pci_disable_device(pdev);
>
> I believe the whole thing isn't necessary at all since the kernel's PCIe
> layer will take care of it.

You mean only the pci_save_state() and pci_disable_device() or, the
resume counterpart as well? Hmm.

Earlier the resume counterpart didn't do any restore stuff and the
device ended up pretty confused..


Micha?
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Johannes Berg March 2, 2015, 9:25 a.m. UTC | #3
On Mon, 2015-03-02 at 10:23 +0100, Michal Kazior wrote:

> > I believe the whole thing isn't necessary at all since the kernel's PCIe
> > layer will take care of it.
> 
> You mean only the pci_save_state() and pci_disable_device() or, the
> resume counterpart as well? Hmm.

Resume as well - but I believe it's all-or-nothing.

> Earlier the resume counterpart didn't do any restore stuff and the
> device ended up pretty confused..

which may explain this.

johannes

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Michal Kazior March 2, 2015, 10:17 a.m. UTC | #4
On 2 March 2015 at 10:25, Johannes Berg <johannes@sipsolutions.net> wrote:
> On Mon, 2015-03-02 at 10:23 +0100, Michal Kazior wrote:
>
>> > I believe the whole thing isn't necessary at all since the kernel's PCIe
>> > layer will take care of it.
>>
>> You mean only the pci_save_state() and pci_disable_device() or, the
>> resume counterpart as well? Hmm.
>
> Resume as well - but I believe it's all-or-nothing.
>
>> Earlier the resume counterpart didn't do any restore stuff and the
>> device ended up pretty confused..
>
> which may explain this.

Hmm.. I removed the save/restore/enable/disable completely and
re-tested. It seems to work fine as well.

I'll post a v2 later then. Thanks!


Micha?
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diff mbox

Patch

diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index cbf82ff..d06b264 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -2053,24 +2053,15 @@  static void ath10k_pci_hif_power_down(struct ath10k *ar)
 
 #ifdef CONFIG_PM
 
-#define ATH10K_PCI_PM_CONTROL 0x44
-
 static int ath10k_pci_hif_suspend(struct ath10k *ar)
 {
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
 	struct pci_dev *pdev = ar_pci->pdev;
-	u32 val;
 
 	ath10k_pci_sleep(ar);
 
-	pci_read_config_dword(pdev, ATH10K_PCI_PM_CONTROL, &val);
-
-	if ((val & 0x000000ff) != 0x3) {
-		pci_save_state(pdev);
-		pci_disable_device(pdev);
-		pci_write_config_dword(pdev, ATH10K_PCI_PM_CONTROL,
-				       (val & 0xffffff00) | 0x03);
-	}
+	pci_save_state(pdev);
+	pci_disable_device(pdev);
 
 	return 0;
 }
@@ -2088,22 +2079,16 @@  static int ath10k_pci_hif_resume(struct ath10k *ar)
 		return ret;
 	}
 
-	pci_read_config_dword(pdev, ATH10K_PCI_PM_CONTROL, &val);
+	pci_restore_state(pdev);
 
-	if ((val & 0x000000ff) != 0) {
-		pci_restore_state(pdev);
-		pci_write_config_dword(pdev, ATH10K_PCI_PM_CONTROL,
-				       val & 0xffffff00);
-		/*
-		 * Suspend/Resume resets the PCI configuration space,
-		 * so we have to re-disable the RETRY_TIMEOUT register (0x41)
-		 * to keep PCI Tx retries from interfering with C3 CPU state
-		 */
-		pci_read_config_dword(pdev, 0x40, &val);
-
-		if ((val & 0x0000ff00) != 0)
-			pci_write_config_dword(pdev, 0x40, val & 0xffff00ff);
-	}
+	/* Suspend/Resume resets the PCI configuration space, so we have to
+	 * re-disable the RETRY_TIMEOUT register (0x41) to keep PCI Tx retries
+	 * from interfering with C3 CPU state. pci_restore_state won't help
+	 * here since it only restores the first 64 bytes pci config header.
+	 */
+	pci_read_config_dword(pdev, 0x40, &val);
+	if ((val & 0x0000ff00) != 0)
+		pci_write_config_dword(pdev, 0x40, val & 0xffff00ff);
 
 	return ret;
 }