Re: [PATCH] mmc: meson-gx: add SDIO interrupt support

[Heiner Kallweit <hkallweit1@gmail.com>]

On 15.08.2022 20:20, Ulf Hansson wrote:
> On Sun, 14 Aug 2022 at 23:44, Heiner Kallweit <hkallweit1@gmail.com> wrote:
>>
>> This adds SDIO interrupt support.
>> Successfully tested on a S905X4-based system with a BRCM4334
>> SDIO wifi module (brcmfmac driver).
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>> ---
>>  drivers/mmc/host/meson-gx-mmc.c | 45 +++++++++++++++++++++++++--------
>>  1 file changed, 34 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
>> index 2f08d442e..e8d53fcdd 100644
>> --- a/drivers/mmc/host/meson-gx-mmc.c
>> +++ b/drivers/mmc/host/meson-gx-mmc.c
>> @@ -41,14 +41,17 @@
>>  #define   CLK_V2_TX_DELAY_MASK GENMASK(19, 16)
>>  #define   CLK_V2_RX_DELAY_MASK GENMASK(23, 20)
>>  #define   CLK_V2_ALWAYS_ON BIT(24)
>> +#define   CLK_V2_IRQ_SDIO_SLEEP BIT(29)
>>
>>  #define   CLK_V3_TX_DELAY_MASK GENMASK(21, 16)
>>  #define   CLK_V3_RX_DELAY_MASK GENMASK(27, 22)
>>  #define   CLK_V3_ALWAYS_ON BIT(28)
>> +#define   CLK_V3_IRQ_SDIO_SLEEP BIT(29)
>>
>>  #define   CLK_TX_DELAY_MASK(h)         (h->data->tx_delay_mask)
>>  #define   CLK_RX_DELAY_MASK(h)         (h->data->rx_delay_mask)
>>  #define   CLK_ALWAYS_ON(h)             (h->data->always_on)
>> +#define   CLK_IRQ_SDIO_SLEEP(h)                (h->data->irq_sdio_sleep)
>>
>>  #define SD_EMMC_DELAY 0x4
>>  #define SD_EMMC_ADJUST 0x8
>> @@ -100,9 +103,6 @@
>>  #define   IRQ_END_OF_CHAIN BIT(13)
>>  #define   IRQ_RESP_STATUS BIT(14)
>>  #define   IRQ_SDIO BIT(15)
>> -#define   IRQ_EN_MASK \
>> -       (IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN | IRQ_RESP_STATUS |\
>> -        IRQ_SDIO)
>>
>>  #define SD_EMMC_CMD_CFG 0x50
>>  #define SD_EMMC_CMD_ARG 0x54
>> @@ -136,6 +136,7 @@ struct meson_mmc_data {
>>         unsigned int rx_delay_mask;
>>         unsigned int always_on;
>>         unsigned int adjust;
>> +       unsigned int irq_sdio_sleep;
>>  };
>>
>>  struct sd_emmc_desc {
>> @@ -431,6 +432,7 @@ static int meson_mmc_clk_init(struct meson_host *host)
>>         clk_reg |= FIELD_PREP(CLK_CORE_PHASE_MASK, CLK_PHASE_180);
>>         clk_reg |= FIELD_PREP(CLK_TX_PHASE_MASK, CLK_PHASE_0);
>>         clk_reg |= FIELD_PREP(CLK_RX_PHASE_MASK, CLK_PHASE_0);
>> +       clk_reg |= CLK_IRQ_SDIO_SLEEP(host);
>>         writel(clk_reg, host->regs + SD_EMMC_CLOCK);
>>
>>         /* get the mux parents */
>> @@ -933,7 +935,6 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
>>  {
>>         struct meson_host *host = dev_id;
>>         struct mmc_command *cmd;
>> -       struct mmc_data *data;
>>         u32 irq_en, status, raw_status;
>>         irqreturn_t ret = IRQ_NONE;
>>
>> @@ -948,14 +949,24 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
>>                 return IRQ_NONE;
>>         }
>>
>> -       if (WARN_ON(!host) || WARN_ON(!host->cmd))
>> +       if (WARN_ON(!host))
>>                 return IRQ_NONE;
>>
>>         /* ack all raised interrupts */
>>         writel(status, host->regs + SD_EMMC_STATUS);
>>
>>         cmd = host->cmd;
>> -       data = cmd->data;
>> +
>> +       if (status & IRQ_SDIO) {
>> +               mmc_signal_sdio_irq(host->mmc);
> 
> This is the legacy interface for supporting SDIO irqs. I am planning
> to remove it, sooner or later.
> 
> Please convert into using sdio_signal_irq() instead. Note that, using
> sdio_signal_irq() means you need to implement support for
> MMC_CAP2_SDIO_IRQ_NOTHREAD, which also includes to implement the
> ->ack_sdio_irq() callback.
> 
> There are other host drivers to be inspired from, but don't hesitate
> to ask if there is something unclear.
> 

I switched to the new API and it works for me, will submit a v2.

Just one question regarding core code:
The core defines sdio_irq_work as delayed work, but no caller sets a delay.
Then why not use a simple workqueue and schedule_work() instead of
queue_delayed_work()?

> [...]
> 
> Kind regards
> Uffe


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