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Message-ID: <2e99224b-cf32-457f-9c5d-38d93731e208@intel.com>
Date: Mon, 4 Mar 2024 17:15:55 +0200
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Subject: Re: [PATCH v5 2/2] mmc: sdhci-of-dwcmshc: Implement SDHCI CQE support
Content-Language: en-US
To: Sergey Khimich <serghox@gmail.com>, linux-mmc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Ulf Hansson <ulf.hansson@linaro.org>,
 Shawn Lin <shawn.lin@rock-chips.com>, Jyan Chou <jyanchou@realtek.com>
References: <20231231144619.758290-1-serghox@gmail.com>
 <20231231144619.758290-3-serghox@gmail.com>
 <8eecede9-23b6-48dd-90e2-68e1f2722830@intel.com>
 <72c67d56-ea70-4348-b1a0-895c319b3aef@gmail.com>
From: Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
 Business Identity Code: 0357606 - 4, Domiciled in Helsinki
In-Reply-To: <72c67d56-ea70-4348-b1a0-895c319b3aef@gmail.com>
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On 4/03/24 16:30, Sergey Khimich wrote:
> Hello Adrian!
> 
> Sorry for the late reply. Thanks for the comments - I`ll fix the next patch set version.
> 
> On 03.01.2024 21:52, Adrian Hunter wrote:
>> On 31/12/23 16:46, Sergey Khimich wrote:
>>> From: Sergey Khimich <serghox@gmail.com>
>>>
>>> For enabling CQE support just set 'supports-cqe' in your DevTree file
>>> for appropriate mmc node.
>>>
>>> Signed-off-by: Sergey Khimich <serghox@gmail.com>
>>> ---
>>>   drivers/mmc/host/Kconfig            |   1 +
>>>   drivers/mmc/host/sdhci-of-dwcmshc.c | 181 +++++++++++++++++++++++++++-
>>>   2 files changed, 180 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
>>> index 58bd5fe4cd25..f7594705b013 100644
>>> --- a/drivers/mmc/host/Kconfig
>>> +++ b/drivers/mmc/host/Kconfig
>>> @@ -233,6 +233,7 @@ config MMC_SDHCI_OF_DWCMSHC
>>>       depends on MMC_SDHCI_PLTFM
>>>       depends on OF
>>>       depends on COMMON_CLK
>>> +    select MMC_CQHCI
>>>       help
>>>         This selects Synopsys DesignWare Cores Mobile Storage Controller
>>>         support.
>>> diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
>>> index 3a3bae6948a8..0ba1df4bcf36 100644
>>> --- a/drivers/mmc/host/sdhci-of-dwcmshc.c
>>> +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
>>> @@ -20,6 +20,7 @@
>>>   #include <linux/sizes.h>
>>>     #include "sdhci-pltfm.h"
>>> +#include "cqhci.h"
>>>     #define SDHCI_DWCMSHC_ARG2_STUFF    GENMASK(31, 16)
>>>   @@ -36,6 +37,9 @@
>>>   #define DWCMSHC_ENHANCED_STROBE        BIT(8)
>>>   #define DWCMSHC_EMMC_ATCTRL        0x40
>>>   +/* DWC IP vendor area 2 pointer */
>>> +#define DWCMSHC_P_VENDOR_AREA2        0xea
>>> +
>>>   /* Rockchip specific Registers */
>>>   #define DWCMSHC_EMMC_DLL_CTRL        0x800
>>>   #define DWCMSHC_EMMC_DLL_RXCLK        0x804
>>> @@ -75,6 +79,11 @@
>>>   #define BOUNDARY_OK(addr, len) \
>>>       ((addr | (SZ_128M - 1)) == ((addr + len - 1) | (SZ_128M - 1)))
>>>   +#define DWCMSHC_SDHCI_CQE_TRNS_MODE    (SDHCI_TRNS_MULTI | \
>>> +                     SDHCI_TRNS_BLK_CNT_EN | \
>>> +                     SDHCI_TRNS_DMA)
>>> +
>>> +
>>>   enum dwcmshc_rk_type {
>>>       DWCMSHC_RK3568,
>>>       DWCMSHC_RK3588,
>>> @@ -90,7 +99,9 @@ struct rk35xx_priv {
>>>     struct dwcmshc_priv {
>>>       struct clk    *bus_clk;
>>> -    int vendor_specific_area1; /* P_VENDOR_SPECIFIC_AREA reg */
>>> +    int vendor_specific_area1; /* P_VENDOR_SPECIFIC_AREA1 reg */
>>> +    int vendor_specific_area2; /* P_VENDOR_SPECIFIC_AREA2 reg */
>>> +
>>>       void *priv; /* pointer to SoC private stuff */
>>>   };
>>>   @@ -210,6 +221,90 @@ static void dwcmshc_hs400_enhanced_strobe(struct mmc_host *mmc,
>>>       sdhci_writel(host, vendor, reg);
>>>   }
>>>   +static int dwcmshc_execute_tuning(struct mmc_host *mmc, u32 opcode)
>>> +{
>>> +    int err = sdhci_execute_tuning(mmc, opcode);
>>> +    struct sdhci_host *host = mmc_priv(mmc);
>>> +
>>> +    if (err)
>>> +        return err;
>>> +
>>> +    /*
>>> +     * Tuning can leave the IP in an active state (Buffer Read Enable bit
>>> +     * set) which prevents the entry to low power states (i.e. S0i3). Data
>>> +     * reset will clear it.
>>> +     */
>>> +    sdhci_reset(host, SDHCI_RESET_DATA);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static u32 dwcmshc_cqe_irq_handler(struct sdhci_host *host, u32 intmask)
>>> +{
>>> +    int cmd_error = 0;
>>> +    int data_error = 0;
>>> +
>>> +    if (!sdhci_cqe_irq(host, intmask, &cmd_error, &data_error))
>>> +        return intmask;
>>> +
>>> +    cqhci_irq(host->mmc, intmask, cmd_error, data_error);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static void dwcmshc_sdhci_cqe_enable(struct mmc_host *mmc)
>>> +{
>>> +    struct sdhci_host *host = mmc_priv(mmc);
>>> +    u8 ctrl;
>>> +
>>> +    sdhci_writew(host, DWCMSHC_SDHCI_CQE_TRNS_MODE, SDHCI_TRANSFER_MODE);
>>> +
>>> +    sdhci_cqe_enable(mmc);
>>> +
>>> +    /*
>>> +     * The "DesignWare Cores Mobile Storage Host Controller
>>> +     * DWC_mshc / DWC_mshc_lite Databook" says:
>>> +     * when Host Version 4 Enable" is 1 in Host Control 2 register,
>>> +     * SDHCI_CTRL_ADMA32 bit means ADMA2 is selected.
>>> +     * Selection of 32-bit/64-bit System Addressing:
>>> +     * either 32-bit or 64-bit system addressing is selected by
>>> +     * 64-bit Addressing bit in Host Control 2 register.
>>> +     *
>>> +     * On the other hand the "DesignWare Cores Mobile Storage Host
>>> +     * Controller DWC_mshc / DWC_mshc_lite User Guide" says, that we have to
>>> +     * set DMA_SEL to ADMA2 _only_ mode in the Host Control 2 register.
>>> +     */
>>> +    ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
>>> +    ctrl &= ~SDHCI_CTRL_DMA_MASK;
>>> +    ctrl |= SDHCI_CTRL_ADMA32;
>>> +    sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
>>> +}
>>> +
>>> +static void dwcmshc_set_tran_desc(struct cqhci_host *cq_host, u8 **desc,
>>> +                  dma_addr_t addr, int len, bool end, bool dma64)
>>> +{
>>> +    int tmplen, offset;
>>> +
>>> +    if (likely(!len || BOUNDARY_OK(addr, len))) {
>>> +        cqhci_set_tran_desc(*desc, addr, len, end, dma64);
>>> +        return;
>>> +    }
>>> +
>>> +    offset = addr & (SZ_128M - 1);
>>> +    tmplen = SZ_128M - offset;
>>> +    cqhci_set_tran_desc(*desc, addr, tmplen, false, dma64);
>>> +
>>> +    addr += tmplen;
>>> +    len -= tmplen;
>>> +    *desc += cq_host->trans_desc_len;
>>> +    cqhci_set_tran_desc(*desc, addr, len, end, dma64);
>>> +}
>>> +
>>> +static void dwcmshc_cqhci_dumpregs(struct mmc_host *mmc)
>>> +{
>>> +    sdhci_dumpregs(mmc_priv(mmc));
>>> +}
>>> +
>>>   static void dwcmshc_rk3568_set_clock(struct sdhci_host *host, unsigned int clock)
>>>   {
>>>       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>> @@ -345,6 +440,7 @@ static const struct sdhci_ops sdhci_dwcmshc_ops = {
>>>       .get_max_clock        = dwcmshc_get_max_clock,
>>>       .reset            = sdhci_reset,
>>>       .adma_write_desc    = dwcmshc_adma_write_desc,
>>> +    .irq            = dwcmshc_cqe_irq_handler,
>>>   };
>>>     static const struct sdhci_ops sdhci_dwcmshc_rk35xx_ops = {
>>> @@ -379,6 +475,71 @@ static const struct sdhci_pltfm_data sdhci_dwcmshc_rk35xx_pdata = {
>>>              SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
>>>   };
>>>   +static const struct cqhci_host_ops dwcmshc_cqhci_ops = {
>>> +    .enable        = dwcmshc_sdhci_cqe_enable,
>>> +    .disable    = sdhci_cqe_disable,
>>> +    .dumpregs    = dwcmshc_cqhci_dumpregs,
>>> +    .set_tran_desc    = dwcmshc_set_tran_desc,
>>> +};
>>> +
>>> +static void dwcmshc_cqhci_init(struct sdhci_host *host, struct platform_device *pdev)
>>> +{
>>> +    struct cqhci_host *cq_host;
>>> +    struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>> +    struct dwcmshc_priv *priv = sdhci_pltfm_priv(pltfm_host);
>>> +    bool dma64 = false;
>>> +    u16 clk;
>>> +    int err;
>>> +
>>> +    host->mmc->caps2 |= MMC_CAP2_CQE | MMC_CAP2_CQE_DCMD;
>>> +    cq_host = devm_kzalloc(&pdev->dev, sizeof(*cq_host), GFP_KERNEL);
>>> +    if (!cq_host) {
>>> +        dev_err(mmc_dev(host->mmc), "Unable to setup CQE: not enough memory\n");
>>> +        return;
>>> +    }
>>> +
>>> +    /*
>>> +     * For dwcmshc host controller we have to enable internal clock
>>> +     * before access to some registers from Vendor Specific Aria 2.
>> Aria -> Area
>>
>>> +     */
>>> +    clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
>>> +    clk |= SDHCI_CLOCK_INT_EN;
>>> +    sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
>>> +    clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
>>> +    if (!(clk & SDHCI_CLOCK_INT_EN)) {
>>> +        dev_err(mmc_dev(host->mmc), "Unable to setup CQE: internal clock enable error\n");
>>> +        goto free_cq_host;
>>> +    }
>>> +
>>> +    cq_host->mmio = host->ioaddr + priv->vendor_specific_area2;
>>> +    cq_host->ops = &dwcmshc_cqhci_ops;
>>> +
>>> +    /* Enable using of 128-bit task descriptors */
>>> +    dma64 = host->flags & SDHCI_USE_64_BIT_DMA;
>>> +    if (dma64) {
>>> +        dev_dbg(mmc_dev(host->mmc), "128-bit task descriptors\n");
>>> +        cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
>>> +    }
>>> +    err = cqhci_init(cq_host, host->mmc, dma64);
>>> +    if (err) {
>>> +        dev_err(mmc_dev(host->mmc), "Unable to setup CQE: error %d\n", err);
>>> +        goto int_clock_disable;
>>> +    }
>>> +
>>> +    dev_dbg(mmc_dev(host->mmc), "CQE init done\n");
>>> +
>>> +    return;
>>> +
>>> +int_clock_disable:
>>> +    clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
>>> +    clk &= ~SDHCI_CLOCK_INT_EN;
>>> +    sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
>>> +
>>> +free_cq_host:
>>> +    devm_kfree(&pdev->dev, cq_host);
>>> +}
>>> +
>>> +
>>>   static int dwcmshc_rk35xx_init(struct sdhci_host *host, struct dwcmshc_priv *dwc_priv)
>>>   {
>>>       int err;
>>> @@ -471,7 +632,7 @@ static int dwcmshc_probe(struct platform_device *pdev)
>>>       struct rk35xx_priv *rk_priv = NULL;
>>>       const struct sdhci_pltfm_data *pltfm_data;
>>>       int err;
>>> -    u32 extra;
>>> +    u32 extra, caps;
>>>         pltfm_data = device_get_match_data(&pdev->dev);
>>>       if (!pltfm_data) {
>>> @@ -519,9 +680,12 @@ static int dwcmshc_probe(struct platform_device *pdev)
>>>         priv->vendor_specific_area1 =
>>>           sdhci_readl(host, DWCMSHC_P_VENDOR_AREA1) & DWCMSHC_AREA1_MASK;
>>> +    priv->vendor_specific_area2 =
>>> +        sdhci_readw(host, DWCMSHC_P_VENDOR_AREA2);
>> Is this OK for all IPs? ie. do they all have DWCMSHC_P_VENDOR_AREA2 register?
> Good question. Actually I can't guarantee that all dwcmshc-like IPs have DWCMSHC_P_VENDOR_AREA2 register,
> because I`ve tested my patch only on my pre-selicon FPGA prototype.
> But on the other hand according to the documentation I have, CQE-related registers are placed within this
> vendor2 block register. And thanks to Shawn Lin we know, Rockchip SoCs with this IP also have this reg.
> As I understand CQE for dwcmshc-like IPs will not work without DWCMSHC_P_VENDOR_AREA2.

Maybe it should be read only in that case? For example, after:

	if (device_property_read_bool(&pdev->dev, "supports-cqe")) {