Date: Mon, 4 Mar 2024 17:30:05 +0300
From: Sergey Khimich <serghox@...il.com>
To: Adrian Hunter <adrian.hunter@...el.com>, linux-mmc@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, Ulf Hansson <ulf.hansson@...aro.org>,
 Shawn Lin <shawn.lin@...k-chips.com>, Jyan Chou <jyanchou@...ltek.com>
Subject: Re: [PATCH v5 2/2] mmc: sdhci-of-dwcmshc: Implement SDHCI CQE support

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@...il.com>
>>
>> For enabling CQE support just set 'supports-cqe' in your DevTree file
>> for appropriate mmc node.
>>
>> Signed-off-by: Sergey Khimich <serghox@...il.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.
>
>>   
>>   	host->mmc_host_ops.request = dwcmshc_request;
>>   	host->mmc_host_ops.hs400_enhanced_strobe = dwcmshc_hs400_enhanced_strobe;
>> +	host->mmc_host_ops.execute_tuning = dwcmshc_execute_tuning;
>>   
>>   	if (pltfm_data == &sdhci_dwcmshc_rk35xx_pdata) {
>>   		rk_priv = devm_kzalloc(&pdev->dev, sizeof(struct rk35xx_priv), GFP_KERNEL);
>> @@ -547,6 +711,10 @@ static int dwcmshc_probe(struct platform_device *pdev)
>>   		sdhci_enable_v4_mode(host);
>>   #endif
>>   
>> +	caps = sdhci_readl(host, SDHCI_CAPABILITIES);
>> +	if (caps & SDHCI_CAN_64BIT_V4)
>> +		sdhci_enable_v4_mode(host);
>> +
>>   	host->mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY;
>>   
>>   	pm_runtime_get_noresume(dev);
>> @@ -557,6 +725,15 @@ static int dwcmshc_probe(struct platform_device *pdev)
>>   	if (err)
>>   		goto err_rpm;
>>   
>> +	/* Setup Command Queue Engine if enabled */
>> +	if (device_property_read_bool(&pdev->dev, "supports-cqe")) {
>> +		if (caps & SDHCI_CAN_64BIT_V4)
>> +			dwcmshc_cqhci_init(host, pdev);
>> +		else
>> +			dev_warn(dev, "Cannot enable CQE without V4 mode support\n");
>> +	}
>> +
>> +
> Double blank line.
>
>>   	if (rk_priv)
>>   		dwcmshc_rk35xx_postinit(host, priv);
>>   

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