linux-kernel - Re: [Patch v5 1/4] memory: tegra: Add memory controller channels support

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Date:   Tue, 22 Mar 2022 21:43:52 +0530
From:   Ashish Mhetre <amhetre@...dia.com>
To:     Dmitry Osipenko <digetx@...il.com>,
        krzysztof.kozlowski@...onical.com, robh+dt@...nel.org,
        thierry.reding@...il.com, jonathanh@...dia.com,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-tegra@...r.kernel.org
Cc:     vdumpa@...dia.com, Snikam@...dia.com
Subject: Re: [Patch v5 1/4] memory: tegra: Add memory controller channels
 support



On 3/19/2022 9:12 PM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
> 
> 
> 16.03.2022 12:25, Ashish Mhetre пишет:
>>  From tegra186 onwards, memory controller support multiple channels.
>> Add support for mapping address spaces of these channels.
>> Make sure that number of channels are as expected on each SOC.
>> During error interrupts from memory controller, appropriate registers
>> from these channels need to be accessed for logging error info.
>>
>> Signed-off-by: Ashish Mhetre <amhetre@...dia.com>
>> ---
>>   drivers/memory/tegra/mc.c       |  6 ++++
>>   drivers/memory/tegra/tegra186.c | 52 +++++++++++++++++++++++++++++++++
>>   drivers/memory/tegra/tegra194.c |  1 +
>>   drivers/memory/tegra/tegra234.c |  1 +
>>   include/soc/tegra/mc.h          |  7 +++++
>>   5 files changed, 67 insertions(+)
>>
>> diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
>> index bf3abb6d8354..3cda1d9ad32a 100644
>> --- a/drivers/memory/tegra/mc.c
>> +++ b/drivers/memory/tegra/mc.c
>> @@ -749,6 +749,12 @@ static int tegra_mc_probe(struct platform_device *pdev)
>>        if (IS_ERR(mc->regs))
>>                return PTR_ERR(mc->regs);
>>
>> +     if (mc->soc->ops && mc->soc->ops->map_regs) {
>> +             err = mc->soc->ops->map_regs(mc, pdev);
>> +             if (err < 0)
>> +                     return err;
>> +     }
>> +
>>        mc->debugfs.root = debugfs_create_dir("mc", NULL);
>>
>>        if (mc->soc->ops && mc->soc->ops->probe) {
>> diff --git a/drivers/memory/tegra/tegra186.c b/drivers/memory/tegra/tegra186.c
>> index 3d153881abc1..a8a45e6ff1f1 100644
>> --- a/drivers/memory/tegra/tegra186.c
>> +++ b/drivers/memory/tegra/tegra186.c
>> @@ -139,11 +139,62 @@ static int tegra186_mc_probe_device(struct tegra_mc *mc, struct device *dev)
>>        return 0;
>>   }
>>
>> +static int tegra186_mc_map_regs(struct tegra_mc *mc,
>> +                             struct platform_device *pdev)
>> +{
>> +     struct device_node *np = pdev->dev.parent->of_node;
>> +     int num_dt_channels, reg_cells = 0;
>> +     struct resource *res;
>> +     int i, ret;
>> +     u32 val;
>> +
>> +     ret = of_property_read_u32(np, "#address-cells", &val);
>> +     if (ret) {
>> +             dev_err(&pdev->dev, "missing #address-cells property\n");
>> +             return ret;
>> +     }
>> +
>> +     reg_cells = val;
>> +
>> +     ret = of_property_read_u32(np, "#size-cells", &val);
>> +     if (ret) {
>> +             dev_err(&pdev->dev, "missing #size-cells property\n");
>> +             return ret;
>> +     }
>> +
>> +     reg_cells += val;
>> +
>> +     num_dt_channels = of_property_count_elems_of_size(pdev->dev.of_node, "reg",
>> +                                                       reg_cells * sizeof(u32));
>> +     /*
>> +      * On tegra186 onwards, memory controller support multiple channels.
>> +      * Apart from regular memory controller channels, there is one broadcast
>> +      * channel and one for stream-id registers.
>> +      */
>> +     if (num_dt_channels < mc->soc->num_channels + 2) {
>> +             dev_warn(&pdev->dev, "MC channels are missing, please update\n");
> 
> Update what >
"Update memory controller DT node with MC channels". Yes, it's unclear.
I will update in next version.

>> +             return 0;
>> +     }
>> +
>> +     mc->mcb_regs = devm_platform_get_and_ioremap_resource(pdev, 1, &res);
> 
> Can't we name each reg bank individually in the DT and then use
> devm_platform_ioremap_resource_byname()?
> 
> ...
>> @@ -212,6 +217,8 @@ struct tegra_mc {
>>        struct tegra_smmu *smmu;
>>        struct gart_device *gart;
>>        void __iomem *regs;
>> +     void __iomem *mcb_regs;
>> +     void __iomem *mc_regs[MC_MAX_CHANNELS];
> 
> s/mc_regs/ch_regs/ ?
Sure, will update in next version.