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Subject: Re: [PATCH v1 2/2] mtd: spi-nor: cadence-quadspi: disable the DMA,
 DAC and auto poll
To:     Vignesh Raghavendra <vigneshr@ti.com>,
        linux-mtd@lists.infradead.org
Cc:     devicetree@vger.kernel.org, boris.brezillon@free-electrons.com,
        richard@nod.at, linux-kernel@vger.kernel.org,
        david.oberhollenzer@sigma-star.at, jwboyer@gmail.com,
        computersforpeace@gmail.com, dwmw2@infradead.org,
        cyrille.pitchen@atmel.com
References: <20190819115424.41479-1-vadivel.muruganx.ramuthevar@linux.intel.com>
 <20190819115424.41479-2-vadivel.muruganx.ramuthevar@linux.intel.com>
 <53dcc9a9-6adb-a1de-cfb4-11a68e5d3d4c@ti.com>
From:   "Ramuthevar, Vadivel MuruganX" 
        <vadivel.muruganx.ramuthevar@linux.intel.com>
Message-ID: <1738897e-7d77-aecd-cc36-6a0fb32fc121@linux.intel.com>
Date:   Fri, 23 Aug 2019 13:18:59 +0800
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Hi Vignesh,

On 22/8/2019 5:03 PM, Vignesh Raghavendra wrote:
> Hi,
>
> On 19/08/19 5:24 PM, Ramuthevar, Vadivel MuruganX wrote:
>> From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
>>
>> On Intel Lightening Mountain(LGM) SoCs QSPI controller do not use
> s/Lightening/Lightning

Thank you so much for the review comments and your time.

(Intel -> Intel's , Lightening -> Lightning) will update

>> Direct Memory Access(DMA), Direct Access Controller(DAC) and
>> auto-poll features. This patch introduces to properly disable DMA,
>> DAC for data transfer instead it uses indirect data transfer.
>> and also auto polling.
>>
> Please split into two patch, one disabling DAC mode and DMA and other
> disabling auto polling feature.
Agreed!
>> Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
>> ---
>>   drivers/mtd/spi-nor/Kconfig           |  2 +-
>>   drivers/mtd/spi-nor/cadence-quadspi.c | 62 ++++++++++++++++++++++++++++++-----
>>   2 files changed, 55 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
>> index 6de83277ce8b..ba2e372ae514 100644
>> --- a/drivers/mtd/spi-nor/Kconfig
>> +++ b/drivers/mtd/spi-nor/Kconfig
>> @@ -34,7 +34,7 @@ config SPI_ASPEED_SMC
>>   
>>   config SPI_CADENCE_QUADSPI
>>   	tristate "Cadence Quad SPI controller"
>> -	depends on OF && (ARM || ARM64 || COMPILE_TEST)
>> +	depends on OF && (ARM || ARM64 || COMPILE_TEST || X86)
>>   	help
>>   	  Enable support for the Cadence Quad SPI Flash controller.
>>   
>> diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
>> index 67f15a1f16fd..83ae28e055f4 100644
>> --- a/drivers/mtd/spi-nor/cadence-quadspi.c
>> +++ b/drivers/mtd/spi-nor/cadence-quadspi.c
>> @@ -67,6 +67,7 @@ struct cqspi_st {
>>   
>>   	void __iomem		*iobase;
>>   	void __iomem		*ahb_base;
>> +	resource_size_t		ahb_phy_addr;
> What does this represent? trigger address to be programmed in
> CQSPI_REG_INDIRECTTRIGGER reg? If so why not use cdns,trigger-address
> property?

  indirect operations are controlled and triggered by software via 
specific APB control/configuration registers instead of AHB access  to 
flash data.

Yes , sure will use the trigger-address property.

>>   	resource_size_t		ahb_size;
>>   	struct completion	transfer_complete;
>>   	struct mutex		bus_mutex;
>> @@ -134,6 +135,8 @@ struct cqspi_driver_platdata {
>>   #define CQSPI_REG_RD_INSTR_TYPE_DATA_MASK	0x3
>>   #define CQSPI_REG_RD_INSTR_DUMMY_MASK		0x1F
>>   
>> +#define CQSPI_REG_WR_COMPLETION_CTRL	0x38
>> +#define CQSPI_REG_WR_COMPLETION_DISABLE_AUTO_POLL	BIT(14)
>>   #define CQSPI_REG_WR_INSTR			0x08
>>   #define CQSPI_REG_WR_INSTR_OPCODE_LSB		0
>>   #define CQSPI_REG_WR_INSTR_TYPE_ADDR_LSB	12
>> @@ -214,6 +217,7 @@ struct cqspi_driver_platdata {
>>   #define CQSPI_REG_INDIRECTWRWATERMARK		0x74
>>   #define CQSPI_REG_INDIRECTWRSTARTADDR		0x78
>>   #define CQSPI_REG_INDIRECTWRBYTES		0x7C
>> +#define CQSPI_REG_INDIRECTTRIGGERADDRRANGE	0x80
>>   
> Where is this used? Lets not add defines without a code snippet using it.
agreed, remove it.
>>   #define CQSPI_REG_CMDADDRESS			0x94
>>   #define CQSPI_REG_CMDREADDATALOWER		0xA0
>> @@ -470,6 +474,18 @@ static int cqspi_command_write_addr(struct spi_nor *nor,
>>   	return cqspi_exec_flash_cmd(cqspi, reg);
>>   }
>>   
>> +static int cqspi_disable_auto_poll(struct cqspi_st *cqspi)
>> +{
>> +	void __iomem *reg_base = cqspi->iobase;
>> +	unsigned int reg;
>> +
>> +	reg = readl(reg_base + CQSPI_REG_WR_COMPLETION_CTRL);
>> +	reg |= CQSPI_REG_WR_COMPLETION_DISABLE_AUTO_POLL;
>> +	writel(reg, reg_base + CQSPI_REG_WR_COMPLETION_CTRL);
>> +
>> +	return 0;
>> +}
>> +
>>   static int cqspi_read_setup(struct spi_nor *nor)
>>   {
>>   	struct cqspi_flash_pdata *f_pdata = nor->priv;
>> @@ -507,6 +523,11 @@ static int cqspi_read_setup(struct spi_nor *nor)
>>   	reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
>>   	reg |= (nor->addr_width - 1);
>>   	writel(reg, reg_base + CQSPI_REG_SIZE);
>> +
>> +	/* Disable auto-polling */
>> +	if (!f_pdata->use_direct_mode)
>> +		cqspi_disable_auto_poll(cqspi);
>> +
> This is a one time setup. So move this to cqspi_controller_init(). More
> comments at the end of the patch
Agreed
>>   	return 0;
>>   }
>>   
>> @@ -517,12 +538,16 @@ static int cqspi_indirect_read_execute(struct spi_nor *nor, u8 *rxbuf,
>>   	struct cqspi_st *cqspi = f_pdata->cqspi;
>>   	void __iomem *reg_base = cqspi->iobase;
>>   	void __iomem *ahb_base = cqspi->ahb_base;
>> +	resource_size_t ahb_phy_addr = cqspi->ahb_phy_addr;
>>   	unsigned int remaining = n_rx;
>>   	unsigned int mod_bytes = n_rx % 4;
>>   	unsigned int bytes_to_read = 0;
>>   	u8 *rxbuf_end = rxbuf + n_rx;
>>   	int ret = 0;
>>   
>> +	if (!f_pdata->use_direct_mode)
>> +		writel(ahb_phy_addr, reg_base + CQSPI_REG_INDIRECTTRIGGER);
>> +
> Drop this and use cdns,trigger-address DT property which takes care of
> programming CQSPI_REG_INDIRECTTRIGGER in cqspi_controller_init()
Agreed
>>   	writel(from_addr, reg_base + CQSPI_REG_INDIRECTRDSTARTADDR);
>>   	writel(remaining, reg_base + CQSPI_REG_INDIRECTRDBYTES);
>>   
>> @@ -609,6 +634,14 @@ static int cqspi_write_setup(struct spi_nor *nor)
>>   	struct cqspi_st *cqspi = f_pdata->cqspi;
>>   	void __iomem *reg_base = cqspi->iobase;
>>   
>> +	/* Disable the DMA and direct access controller */
>> +	if (!f_pdata->use_direct_mode) {
>> +		reg = readl(reg_base + CQSPI_REG_CONFIG);
>> +		reg &= ~CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
>> +		reg &= ~CQSPI_REG_CONFIG_DMA_MASK;
> DMA is disabled by default right? No need to clear it explicitly.

On Intel LGM SoC there is no DMA, in-case of it if enabled , system may 
crash that is the reason, we are disabling it.

Let me double confirm the code changes and validate on platform.

>> +		writel(reg, reg_base + CQSPI_REG_CONFIG);
>> +	}
>> +
> And Move this hunk to cqspi_controller_init()
Sure
>>   	/* Set opcode. */
>>   	reg = nor->program_opcode << CQSPI_REG_WR_INSTR_OPCODE_LSB;
>>   	writel(reg, reg_base + CQSPI_REG_WR_INSTR);
>> @@ -619,6 +652,11 @@ static int cqspi_write_setup(struct spi_nor *nor)
>>   	reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
>>   	reg |= (nor->addr_width - 1);
>>   	writel(reg, reg_base + CQSPI_REG_SIZE);
>> +
>> +	/* Disable auto-polling */
>> +	if (!f_pdata->use_direct_mode)
>> +		cqspi_disable_auto_poll(cqspi);
>> +
>>   	return 0;
>>   }
>>   
>> @@ -1165,13 +1203,16 @@ static int cqspi_of_get_pdata(struct platform_device *pdev)
>>   		return -ENXIO;
>>   	}
>>   
>> -	if (of_property_read_u32(np, "cdns,trigger-address",
>> -				 &cqspi->trigger_address)) {
>> -		dev_err(&pdev->dev, "couldn't determine trigger-address\n");
>> -		return -ENXIO;
>> -	}
>> +	if (!of_device_is_compatible(np, "intel,lgm-qspi")) {
>> +		if (of_property_read_u32(np, "cdns,trigger-address",
>> +					 &cqspi->trigger_address)) {
>> +			dev_err(&pdev->dev,
>> +				"couldn't determine trigger-address\n");
>> +			return -ENXIO;
>> +		}
>>   
> Why? Can you populate cdns,trigger-address with same address as
> res_ahb->start? That should eliminate need for cqspi->ahb_phy_addr

functionality not worked during the development time, better check and 
validate, try to use

the same available as you have suggested.

>> -	cqspi->rclk_en = of_property_read_bool(np, "cdns,rclk-en");
>> +		cqspi->rclk_en = of_property_read_bool(np, "cdns,rclk-en");
>> +	}
>>   
>>   	return 0;
>>   }
>> @@ -1301,7 +1342,8 @@ static int cqspi_setup_flash(struct cqspi_st *cqspi, struct device_node *np)
>>   		f_pdata->registered = true;
>>   
>>   		if (mtd->size <= cqspi->ahb_size) {
>> -			f_pdata->use_direct_mode = true;
>> +			f_pdata->use_direct_mode =
>> +				!(of_device_is_compatible(np, "intel,lgm-qspi"));
> Instead, introduce a new quirk (similar to CQSPI_NEEDS_WR_DELAY) and
> then use the flag to determine when to set use_direct_mode flag. Flag
> can also be used to disable DAC mode in cqspi_controller_init().
>
> And also use cqspi_driver_platdata to populate quirks for the  compatible
Agreed
>>   			dev_dbg(nor->dev, "using direct mode for %s\n",
>>   				mtd->name);
>>   
>> @@ -1347,7 +1389,10 @@ static int cqspi_probe(struct platform_device *pdev)
>>   	}
>>   
>>   	/* Obtain QSPI clock. */
>> -	cqspi->clk = devm_clk_get(dev, NULL);
>> +	if (of_device_is_compatible(np, "intel,lgm-qspi"))
>> +		cqspi->clk = devm_clk_get(dev, "qspi");
>> +	else
>> +		cqspi->clk = devm_clk_get(dev, NULL);
> Does IP have more than 1 clock input? If yes, please document all input
> clk names in Documentation/devicetree/bindings/mtd/cadence-quadspi.txt.
>
> Also,  can be simplified to:
>
> 	cqspi->clk = devm_clk_get(dev, "qspi");
> 	if (IS_ERR(cqspi->clk))
> 		/* Try w/o clk id */
> 		cqspi->clk = devm_clk_get(dev, NULL);
>
> If there is only one clk input in DT, then just drop above code.

IP need only one clock.

will update and address your comments in next version patch-set.

---
With Best Regards
Vadivel Murugan
>>   	if (IS_ERR(cqspi->clk)) {
>>   		dev_err(dev, "Cannot claim QSPI clock.\n");
>>   		return PTR_ERR(cqspi->clk);
>> @@ -1369,6 +1414,7 @@ static int cqspi_probe(struct platform_device *pdev)
>>   		return PTR_ERR(cqspi->ahb_base);
>>   	}
>>   	cqspi->mmap_phys_base = (dma_addr_t)res_ahb->start;
>> +	cqspi->ahb_phy_addr = res_ahb->start;
>>   	cqspi->ahb_size = resource_size(res_ahb);
>>   
>>   	init_completion(&cqspi->transfer_complete);
>>