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Date:   Wed, 13 Apr 2022 21:29:53 +0300
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Subject: Re: [PATCH v3 07/18] ARM: dts: qcom: reduce pci IO size to 64K for
 ipq8064
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To:     Ansuel Smith <ansuelsmth@gmail.com>
Cc:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jonathan McDowell <noodles@earth.li>
References: <20220309190152.7998-1-ansuelsmth@gmail.com>
 <20220309190152.7998-8-ansuelsmth@gmail.com>
 <a7034b5e-24de-ef17-ae93-c626beb35a41@linaro.org>
 <6256cf8e.1c69fb81.b313c.dd8b@mx.google.com>
From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
In-Reply-To: <6256cf8e.1c69fb81.b313c.dd8b@mx.google.com>
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On 13/04/2022 16:21, Ansuel Smith wrote:
> On Wed, Apr 13, 2022 at 04:19:42PM +0300, Dmitry Baryshkov wrote:
>> On 09/03/2022 22:01, Ansuel Smith wrote:
>>> The current value for pci IO is problematic for ath10k wifi card
>>> commonly connected to ipq8064 SoC.
>>> The current value is probably a typo and is actually uncommon to find
>>> 1MB IO space even on a x86 arch.
>>
>> I checked other Qualcomm platforms (including downstream apq8084.dtsi). All
>> of them list 1MB region as IO space.
>>
>> Interesting enough I couldn't get PCI to work on my IFC6410 (apq8064). It
>> has an ethernet adapter AR8151 sitting on the PCIe bus. The driver probes,
>> transmits packets successfully, but receives only garbage. I'm not sure if
>> it is the hardware or a software problem. Same adapter works fine on db820c.
>>
> 
> I didn't understand if device works correctly without this change.
> The alternative to this, is to change the io space globally for every arm
> target and it was pointed out that it was a strange change to do. 99%
> the 1mb region present on every qcom platform is a copy past error but
> still a region that big worked before some kernel version just because
> the kernel didn't check them.
> So it's both reduce IO in dtsi or extend IO_SPACE_LIMIT for every arm
> target.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

> 
>>> Also with recent changes to the pci
>>> driver, pci1 and pci2 now fails to function as any connected device
>>> fails any reg read/write. Reduce this to 64K as it should be more than
>>> enough and 3 * 64K of total IO space doesn't exceed the IO_SPACE_LIMIT
>>> hardcoded for the ARM arch.
>>>
>>> Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
>>> Tested-by: Jonathan McDowell <noodles@earth.li>
>>> ---
>>>    arch/arm/boot/dts/qcom-ipq8064.dtsi | 6 +++---
>>>    1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/arm/boot/dts/qcom-ipq8064.dtsi b/arch/arm/boot/dts/qcom-ipq8064.dtsi
>>> index e247bf51df01..36bdfc8db3f0 100644
>>> --- a/arch/arm/boot/dts/qcom-ipq8064.dtsi
>>> +++ b/arch/arm/boot/dts/qcom-ipq8064.dtsi
>>> @@ -918,7 +918,7 @@ pcie0: pci@1b500000 {
>>>    			#address-cells = <3>;
>>>    			#size-cells = <2>;
>>> -			ranges = <0x81000000 0 0x0fe00000 0x0fe00000 0 0x00100000   /* downstream I/O */
>>> +			ranges = <0x81000000 0 0x0fe00000 0x0fe00000 0 0x00010000   /* downstream I/O */
>>>    				  0x82000000 0 0x08000000 0x08000000 0 0x07e00000>; /* non-prefetchable memory */
>>>    			interrupts = <GIC_SPI 35 IRQ_TYPE_LEVEL_HIGH>;
>>> @@ -969,7 +969,7 @@ pcie1: pci@1b700000 {
>>>    			#address-cells = <3>;
>>>    			#size-cells = <2>;
>>> -			ranges = <0x81000000 0 0x31e00000 0x31e00000 0 0x00100000   /* downstream I/O */
>>> +			ranges = <0x81000000 0 0x31e00000 0x31e00000 0 0x00010000   /* downstream I/O */
>>>    				  0x82000000 0 0x2e000000 0x2e000000 0 0x03e00000>; /* non-prefetchable memory */
>>>    			interrupts = <GIC_SPI 57 IRQ_TYPE_LEVEL_HIGH>;
>>> @@ -1020,7 +1020,7 @@ pcie2: pci@1b900000 {
>>>    			#address-cells = <3>;
>>>    			#size-cells = <2>;
>>> -			ranges = <0x81000000 0 0x35e00000 0x35e00000 0 0x00100000   /* downstream I/O */
>>> +			ranges = <0x81000000 0 0x35e00000 0x35e00000 0 0x00010000   /* downstream I/O */
>>>    				  0x82000000 0 0x32000000 0x32000000 0 0x03e00000>; /* non-prefetchable memory */
>>>    			interrupts = <GIC_SPI 71 IRQ_TYPE_LEVEL_HIGH>;
>>
>>
>> -- 
>> With best wishes
>> Dmitry
> 


-- 
With best wishes
Dmitry