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SubjectRe: [PATCH v2 10/10] spi: atmel-quadspi: add support for sam9x60 qspi controller
Date


On 01/31/2019 06:32 PM, Boris Brezillon wrote:
> On Thu, 31 Jan 2019 16:15:51 +0000
> <Tudor.Ambarus@microchip.com> wrote:
>
>> From: Tudor Ambarus <tudor.ambarus@microchip.com>
>>
>> The sam9x60 qspi controller uses 2 clocks, one for the peripheral register
>> access, the other for the qspi core and phy. Both are mandatory. It uses
>> dedicated register for Read Instruction Code Register (RICR) and
>> Write Instruction Code Register (WICR). ICR/RICR/WICR have identical
>> fields.
>>
>> Tested with sst26vf064b jedec,spi-nor flash. Backward compatibility test
>> done on sama5d2 qspi controller and mx25l25635e jedec,spi-nor flash.
>>
>> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
>> ---
>> v2:
>> - rework clock handling
>> - reorder setting of register values in set_cfg() calls -> move functions
>> that can fail in the upper part of the function body.
>>
>> drivers/spi/atmel-quadspi.c | 296 +++++++++++++++++++++++++++++++++++---------
>> 1 file changed, 239 insertions(+), 57 deletions(-)
>>
>> diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
>> index d3e76acf8517..80c934f3e479 100644
>> --- a/drivers/spi/atmel-quadspi.c
>> +++ b/drivers/spi/atmel-quadspi.c
>> @@ -19,6 +19,7 @@
>> #include <linux/kernel.h>
>> #include <linux/module.h>
>> #include <linux/of.h>
>> +#include <linux/of_platform.h>
>> #include <linux/platform_device.h>
>> #include <linux/spi/spi-mem.h>
>>
>> @@ -35,7 +36,9 @@
>>
>> #define QSPI_IAR 0x0030 /* Instruction Address Register */
>> #define QSPI_ICR 0x0034 /* Instruction Code Register */
>> +#define QSPI_WICR 0x0034 /* Write Instruction Code Register */
>> #define QSPI_IFR 0x0038 /* Instruction Frame Register */
>> +#define QSPI_RICR 0x003C /* Read Instruction Code Register */
>>
>> #define QSPI_SMR 0x0040 /* Scrambling Mode Register */
>> #define QSPI_SKR 0x0044 /* Scrambling Key Register */
>> @@ -88,7 +91,7 @@
>> #define QSPI_SCR_DLYBS_MASK GENMASK(23, 16)
>> #define QSPI_SCR_DLYBS(n) (((n) << 16) & QSPI_SCR_DLYBS_MASK)
>>
>> -/* Bitfields in QSPI_ICR (Instruction Code Register) */
>> +/* Bitfields in QSPI_ICR (Read/Write Instruction Code Register) */
>> #define QSPI_ICR_INST_MASK GENMASK(7, 0)
>> #define QSPI_ICR_INST(inst) (((inst) << 0) & QSPI_ICR_INST_MASK)
>> #define QSPI_ICR_OPT_MASK GENMASK(23, 16)
>> @@ -113,6 +116,8 @@
>> #define QSPI_IFR_OPTL_4BIT (2 << 8)
>> #define QSPI_IFR_OPTL_8BIT (3 << 8)
>> #define QSPI_IFR_ADDRL BIT(10)
>> +#define QSPI_IFR_TFRTYP_TRSFR_MEM BIT(12)
>> +#define QSPI_IFR_TFRTYP_TRSFR_REG (0 << 12)
>
> You don't need to define TRSFR_REG, just set QSPI_IFR_TFRTYP_TRSFR_MEM
> when you do a mem transfer and do nothing when this is a regular
> transfer.


I chose to introduce macros with zero value for better code readability. I would
expect that the NOP operations to be optimized at compile time. I will remove them
if you prefer, it will result in fewer lines of code.

>
>> #define QSPI_IFR_TFRTYP_MASK GENMASK(13, 12)
>> #define QSPI_IFR_TFRTYP_TRSFR_READ (0 << 12)
>> #define QSPI_IFR_TFRTYP_TRSFR_READ_MEM (1 << 12)
>
> Looks like the read/write flag is on bit 13. Can we just add

for sama5d2 only

>
> #define QSPI_IFR_TFRTYP_TRSFR_WRITE BIT(13)
>
> and drop all others def? This way the implementation is consistent
> between sam9x60 and sama5d2.

BIT(13) has no meaning for sam9x60. I can drop the macros with zero value for
sama5d2 in a separate patch.

>
>> @@ -121,6 +126,8 @@
>> #define QSPI_IFR_CRM BIT(14)
>> #define QSPI_IFR_NBDUM_MASK GENMASK(20, 16)
>> #define QSPI_IFR_NBDUM(n) (((n) << 16) & QSPI_IFR_NBDUM_MASK)
>> +#define QSPI_IFR_APBTFRTYP_WRITE (0 << 24)
>
> As for the other defs, I don't think you need to define _WRITE.

understood

>
>> +#define QSPI_IFR_APBTFRTYP_READ BIT(24)
>>
>> /* Bitfields in QSPI_SMR (Scrambling Mode Register) */
>> #define QSPI_SMR_SCREN BIT(0)
>> @@ -137,16 +144,37 @@
>> #define QSPI_WPSR_WPVSRC(src) (((src) << 8) & QSPI_WPSR_WPVSRC)
>>
>>
>> +/* Describes register values. */
>> +struct atmel_qspi_cfg {
>> + u32 icr;
>> + u32 iar;
>> + u32 ifr;
>> +};
>> +
>> +struct atmel_qspi_caps;
>> +
>> struct atmel_qspi {
>> void __iomem *regs;
>> void __iomem *mem;
>> struct clk *clk;
>
> Can we rename that on pclk?

will rename it, together with the support for unnamed clock of sama5d2 in a separate
patch. The dt-bindings patch that imposes "pclk" for sama5d2 should be separated too.

>
>> + struct clk *qspick;
>> struct platform_device *pdev;
>> + const struct atmel_qspi_caps *caps;
>> u32 pending;
>> u32 mr;
>> struct completion cmd_completion;
>> };
>>
>
> ...
>
>> +
>> +static int atmel_sam9x60_qspi_set_cfg(void __iomem *base,
>> + const struct spi_mem_op *op,
>> + struct atmel_qspi_cfg *cfg)
>> +{
>> + int ret = atmel_qspi_set_mode(cfg, op);
>> +
>> + if (ret)
>> + return ret;
>> +
>> + ret = atmel_qspi_set_address_mode(cfg, op);
>> + if (ret)
>> + return ret;
>> +
>> + cfg->ifr |= QSPI_IFR_INSTEN;
>> + cfg->icr |= QSPI_ICR_INST(op->cmd.opcode);
>> +
>> + /* Set data enable */
>> + if (op->data.nbytes)
>> + cfg->ifr |= QSPI_IFR_DATAEN;
>> +
>> + if (!op->addr.nbytes) {
>> + cfg->ifr |= QSPI_IFR_TFRTYP_TRSFR_REG;
>> + if (op->data.dir == SPI_MEM_DATA_OUT)
>> + cfg->ifr |= QSPI_IFR_APBTFRTYP_WRITE;
>> + else
>> + cfg->ifr |= QSPI_IFR_APBTFRTYP_READ;
>> + } else {
>> + cfg->ifr |= QSPI_IFR_TFRTYP_TRSFR_MEM;
>
> Can you try doing only regular transfers and let me know if it still
> works. Support for mem transfers can then be added along with dirmap
> support.

should work. Will try and let you know.

>
>> + }
>>
>> /* Clear pending interrupts */
>> (void)readl_relaxed(base + QSPI_SR);
>>
>> /* Set QSPI Instruction Frame registers */
>> - writel_relaxed(iar, base + QSPI_IAR);
>> - writel_relaxed(icr, base + QSPI_ICR);
>> - writel_relaxed(ifr, base + QSPI_IFR);
>> + writel_relaxed(cfg->iar, base + QSPI_IAR);
>> + if (op->data.dir == SPI_MEM_DATA_OUT)
>> + writel_relaxed(cfg->icr, base + QSPI_ICR);
>> + else
>> + writel_relaxed(cfg->icr, base + QSPI_RICR);
>> + writel_relaxed(cfg->ifr, base + QSPI_IFR);
>> +
>> + return 0;
>> +}
>> +
>
> ...
>
>> @@ -443,32 +578,52 @@ static int atmel_qspi_probe(struct platform_device *pdev)
>> /* Enable the peripheral clock */
>> err = clk_prepare_enable(aq->clk);
>> if (err) {
>> - dev_err(&pdev->dev, "failed to enable the peripheral clock\n");
>> + dev_err(dev, "failed to enable the peripheral clock\n");
>> goto exit;
>> }
>>
>> + if (caps->has_qspick) {
>> + /* Get the QSPI system clock */
>> + aq->qspick = devm_clk_get(dev, "qspick");
>> + if (IS_ERR(aq->qspick)) {
>> + dev_err(dev, "missing system clock\n");
>> + err = PTR_ERR(aq->qspick);
>> + goto disable_clk;
>> + }
>> +
>> + /* Enable the QSPI system clock */
>> + err = clk_prepare_enable(aq->qspick);
>> + if (err) {
>> + dev_err(dev,
>> + "failed to enable the QSPI system clock\n");
>> + goto disable_clk;
>> + }
>> + }
>> +
>> /* Request the IRQ */
>> irq = platform_get_irq(pdev, 0);
>> if (irq < 0) {
>> - dev_err(&pdev->dev, "missing IRQ\n");
>> + dev_err(dev, "missing IRQ\n");
>> err = irq;
>> - goto disable_clk;
>> + goto disable_qspick;
>> }
>> - err = devm_request_irq(&pdev->dev, irq, atmel_qspi_interrupt,
>> - 0, dev_name(&pdev->dev), aq);
>> + err = devm_request_irq(dev, irq, atmel_qspi_interrupt, 0,
>> + dev_name(dev), aq);
>> if (err)
>> - goto disable_clk;
>> + goto disable_qspick;
>>
>> err = atmel_qspi_init(aq);
>> if (err)
>> - goto disable_clk;
>> + goto disable_qspick;
>>
>> err = spi_register_controller(ctrl);
>> if (err)
>> - goto disable_clk;
>> + goto disable_qspick;
>>
>> return 0;
>>
>> +disable_qspick:
>> + clk_disable_unprepare(aq->qspick);
>> disable_clk:
>
> We should probably rename this label disable_pclk.

sure. Thanks, Boris!

>
>> clk_disable_unprepare(aq->clk);
>> exit:
>
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