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Date: Fri, 12 Nov 2010 14:16:24 -0500
Message-ID: <AANLkTinE7LE7OXOq+DrUQfwOAjckaV5A3JbGUSD3vp9h@mail.gmail.com>
Subject: Re: [PATCH 9/9] ath5k: AHB port. Fix reset and interrupts for AHB
 type of devices.
From: Bob Copeland <me@bobcopeland.com>
To: Wojciech Dubowik <dubowoj@neratec.com>
Cc: linville@tuxdriver.com, linux-wireless@vger.kernel.org
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Sender: linux-wireless-owner@vger.kernel.org

On Thu, Nov 11, 2010 at 9:58 AM, Wojciech Dubowik <dubowoj@neratec.com> wrote:
> On WiSoc we cannot access mac register before it is resetted.
> Otherwise it will crash hardware.
>
> Signed-off-by: Wojciech Dubowik <Wojciech.Dubowik@neratec.com>
> ---
> ?drivers/net/wireless/ath/ath5k/base.c ?| ? ?7 ++-
> ?drivers/net/wireless/ath/ath5k/reset.c | ?113 ++++++++++++++++++++++++-------
> ?2 files changed, 93 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
> index 13d5da5..00ebb81 100644
> --- a/drivers/net/wireless/ath/ath5k/base.c
> +++ b/drivers/net/wireless/ath/ath5k/base.c
> @@ -2175,7 +2175,8 @@ ath5k_intr(int irq, void *dev_id)
> ? ? ? ?unsigned int counter = 1000;
>
> ? ? ? ?if (unlikely(test_bit(ATH_STAT_INVALID, sc->status) ||
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? !ath5k_hw_is_intr_pending(ah)))
> + ? ? ? ? ? ? ? ((ath5k_get_bus_type(ah) != ATH_AHB) &&
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? !ath5k_hw_is_intr_pending(ah))))
> ? ? ? ? ? ? ? ?return IRQ_NONE;
>

Hrm, we really don't want to sprinkle these special cases all around
the driver.  Perhaps it'd be better to make sure ATH_STAT_INVALID
isn't set until the soc is ready.  And, in other cases, using
capability bits or something?  Bus type seems a bit crude.

> @@ -2241,6 +2242,10 @@ ath5k_intr(int irq, void *dev_id)
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?tasklet_schedule(&sc->rf_kill.toggleq);
>
> ? ? ? ? ? ? ? ?}
> +
> + ? ? ? ? ? ? ? if(ath5k_get_bus_type(ah) == ATH_AHB)
> + ? ? ? ? ? ? ? ? ? ? ? break;
> +
> ? ? ? ?} while (ath5k_hw_is_intr_pending(ah) && --counter > 0);

Why?

> ?static int ath5k_hw_nic_reset(struct ath5k_hw *ah, u32 val)
> ?{
> - ? ? ? int ret;
> + ? ? ? int ret = 0;

In general, I dislike assigning ret until the last possible moment,
because leaving it unassigned sometimes catches errors like:

  int ret;

+ if (new_boolean_test)
+     goto out;

  ret = xyz();

  out:
      return ret;

In this particular case it doesn't matter that much, but the
early assignment shouldn't really be needed.


>
> ? ? ? ?/*
> ? ? ? ? * Reset configuration register (for hw byte-swap). Note that this
> @@ -334,6 +377,9 @@ int ath5k_hw_on_hold(struct ath5k_hw *ah)
> ? ? ? ?u32 bus_flags;
> ? ? ? ?int ret;
>
> + ? ? ? if(ath5k_get_bus_type(ah) == ATH_AHB)
> + ? ? ? ? ? ? ? return 0;
> +
> ? ? ? ?/* Make sure device is awake */
> ? ? ? ?ret = ath5k_hw_set_power(ah, AR5K_PM_AWAKE, true, 0);
> ? ? ? ?if (ret) {
> @@ -390,22 +436,30 @@ int ath5k_hw_nic_wakeup(struct ath5k_hw *ah, int flags, bool initial)
> ? ? ? ?mode = 0;
> ? ? ? ?clock = 0;
>
> - ? ? ? /* Wakeup the device */
> - ? ? ? ret = ath5k_hw_set_power(ah, AR5K_PM_AWAKE, true, 0);
> - ? ? ? if (ret) {
> - ? ? ? ? ? ? ? ATH5K_ERR(ah->ah_sc, "failed to wakeup the MAC Chip\n");
> - ? ? ? ? ? ? ? return ret;
> + ? ? ? if(ath5k_get_bus_type(ah) == ATH_AHB && !initial){
> + ? ? ? ? ? ? ? /* Wakeup the device */
> + ? ? ? ? ? ? ? ret = ath5k_hw_set_power(ah, AR5K_PM_AWAKE, true, 0);
> + ? ? ? ? ? ? ? if (ret) {
> + ? ? ? ? ? ? ? ? ? ? ? ATH5K_ERR(ah->ah_sc, "failed to wakeup the MAC Chip\n");
> + ? ? ? ? ? ? ? ? ? ? ? return ret;
> + ? ? ? ? ? ? ? }
> ? ? ? ?}
>
> ? ? ? ?/*
> ? ? ? ? * Put chipset on warm reset...
> ? ? ? ? *
> - ? ? ? ?* Note: putting PCI core on warm reset on PCI-E cards
> - ? ? ? ?* results card to hang and always return 0xffff... so
> - ? ? ? ?* we ingore that flag for PCI-E cards. On PCI cards
> - ? ? ? ?* this flag gets cleared after 64 PCI clocks.
> ? ? ? ? */
> - ? ? ? bus_flags = (pdev && pdev->is_pcie) ? 0 : AR5K_RESET_CTL_PCI;
> + ? ? ? if(ath5k_get_bus_type(ah) == ATH_AHB){
> + ? ? ? ? ? ? ? /* Reset MAC on WiSoc devices */
> + ? ? ? ? ? ? ? bus_flags = (initial) ? AR5K_RESET_CTL_MAC : 0;
> + ? ? ? } else {
> + ? ? ? ? ? ? ? /* Note: putting PCI core on warm reset on PCI-E cards
> + ? ? ? ? ? ? ? ?* results card to hang and always return 0xffff... so
> + ? ? ? ? ? ? ? ?* we ingore that flag for PCI-E cards. On PCI cards
> + ? ? ? ? ? ? ? ?* this flag gets cleared after 64 PCI clocks.
> + ? ? ? ? ? ? ? ?*/
> + ? ? ? ? ? ? ? bus_flags = (pdev && pdev->is_pcie) ? 0 : AR5K_RESET_CTL_PCI;


Maybe ath5k_get_bus_flags or something here.


 + ? ? ? }
>
> ? ? ? ?if (ah->ah_version == AR5K_AR5210) {
> ? ? ? ? ? ? ? ?ret = ath5k_hw_nic_reset(ah, AR5K_RESET_CTL_PCU |
> @@ -536,6 +590,9 @@ static void ath5k_hw_set_sleep_clock(struct ath5k_hw *ah, bool enable)
> ? ? ? ?struct ath5k_eeprom_info *ee = &ah->ah_capabilities.cap_eeprom;
> ? ? ? ?u32 scal, spending, usec32;
>
> + ? ? ? if(ath5k_get_bus_type(ah) == ATH_AHB)
> + ? ? ? ? ? ? ? enable = false;
> +

Do you need this hunk?  We never enable the sleep clock for AP mode.

-- 
Bob Copeland %% www.bobcopeland.com