Re: [PATCH v4 1/2] mtd: rawnand: Add Macronix Raw NAND controller

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi masonccyang@mxic.com.tw,

masonccyang@mxic.com.tw wrote on Fri, 28 Jun 2019 14:01:55 +0800:

> Hi Miquel,
> 
> 
> > > Add a driver for Macronix raw NAND controller.  
> > 
> > Could you pass userspace major MTD tests and can you attach/mount/edit
> > a UBI/UBIFS storage?  
> 
> mtd_debug passed and using dd utility to read and write 
> with md5sum checking passed.

Please don't use dd, use nanddump/nandwrite/flasherase/nandbiterrs and
run the other tests from the mtd-utils test suite (available in
Buildroot for instance).

> 
> UBI/UBIFS testing is not yet. will do it.
> 
> 
> > > +static int mxic_nfc_clk_enable(struct mxic_nand_ctlr *nfc)
> > > +{
> > > +   int ret;
> > > +
> > > +   ret = clk_prepare_enable(nfc->send_clk);
> > > +   if (ret)
> > > +      return ret;
> > > +
> > > +   ret = clk_prepare_enable(nfc->send_dly_clk);
> > > +   if (ret)
> > > +      goto err_send_dly_clk;  
> > 
> > I'm not sure why you only enable 2 out of 3 clocks and also why ou
> > handle two of them here (which is great, I prefer having a separate
> > helper for that) and the other one elsewhere?
> >   
> 
> send_clk and send_dly_clk are device domain clocks.
> 
> send_clk is clock without phase delay to ps_clk, used for sending device
> signals except for SIO[7:0].
> send_dly_clk is clock with phase delay to ps_clk, used for sending 
> SIO[7:0]
> 
> ps_clk is system domain clock and it's a source clock of send_clk and 
> send_dly_clk.

And why is that explaining the fact that you configure them in
different places? You can explain this with a nice comment at the top
of the function, but I would rather prefer that you handle all three
clocks in one go if possible.

> 
> > > +
> > > +   return ret;
> > > +
> > > +err_send_dly_clk:
> > > +   clk_disable_unprepare(nfc->send_clk);
> > > +
> > > +   return ret;
> > > +}
> > > +
> > > +static void mxic_nfc_clk_disable(struct mxic_nand_ctlr *nfc)
> > > +{
> > > +   clk_disable_unprepare(nfc->send_clk);
> > > +   clk_disable_unprepare(nfc->send_dly_clk);
> > > +}
> > > +
> > > +static void mxic_nfc_set_input_delay(struct mxic_nand_ctlr *nfc, u8   
> idly_code)
> > > +{
> > > +   writel(IDLY_CODE_VAL(0, idly_code) |
> > > +          IDLY_CODE_VAL(1, idly_code) |
> > > +          IDLY_CODE_VAL(2, idly_code) |
> > > +          IDLY_CODE_VAL(3, idly_code),
> > > +          nfc->regs + IDLY_CODE(0));
> > > +   writel(IDLY_CODE_VAL(4, idly_code) |
> > > +          IDLY_CODE_VAL(5, idly_code) |
> > > +          IDLY_CODE_VAL(6, idly_code) |
> > > +          IDLY_CODE_VAL(7, idly_code),
> > > +          nfc->regs + IDLY_CODE(1));
> > > +}
> > > +
> > > +static int mxic_nfc_clk_setup(struct mxic_nand_ctlr *nfc, unsigned   
> long freq)
> > > +{
> > > +   int ret;
> > > +
> > > +   ret = clk_set_rate(nfc->send_clk, freq);
> > > +   if (ret)
> > > +      return ret;
> > > +
> > > +   ret = clk_set_rate(nfc->send_dly_clk, freq);
> > > +   if (ret)
> > > +      return ret;
> > > +
> > > +   /*
> > > +    * A constant delay range from 0x0 ~ 0x1F for input delay,
> > > +    * the unit is 78 ps, the max input delay is 2.418 ns.
> > > +    */
> > > +   mxic_nfc_set_input_delay(nfc, 0xf);
> > > +
> > > +   /*
> > > +    * Phase degree = 360 * freq * output-delay
> > > +    * where output-delay is a constant value 1 ns in FPGA.  
> > 
> > Will it always be in FPGA?  
> 
> yes.
> 
> >   
> > > +    *
> > > +    * Get Phase degree = 360 * freq * 1 ns
> > > +    *                  = 360 * freq * 1 sec / 1000000000
> > > +    *                  = 9 * freq / 25000000
> > > +    */
> > > +   ret = clk_set_phase(nfc->send_dly_clk, 9 * freq / 25000000);
> > > +   if (ret)
> > > +      return ret;
> > > +
> > > +   return 0;
> > > +}
> > > +
> > > +static int mxic_nfc_set_freq(struct mxic_nand_ctlr *nfc, unsigned   
> long freq)
> > > +{
> > > +   int ret;
> > > +
> > > +   if (freq > MXIC_NFC_MAX_CLK_HZ)
> > > +      freq = MXIC_NFC_MAX_CLK_HZ;
> > > +
> > > +   mxic_nfc_clk_disable(nfc);
> > > +   ret = mxic_nfc_clk_setup(nfc, freq);
> > > +   if (ret)
> > > +      return ret;
> > > +
> > > +   ret = mxic_nfc_clk_enable(nfc);
> > > +   if (ret)
> > > +      return ret;
> > > +
> > > +   return 0;
> > > +}
> > > +
> > > +static void mxic_nfc_hw_init(struct mxic_nand_ctlr *nfc)
> > > +{
> > > +   writel(DATA_STROB_EDO_EN, nfc->regs + DATA_STROB);
> > > +   writel(HC_CFG_NIO(8) | HC_CFG_TYPE(1, HC_CFG_TYPE_RAW_NAND) |
> > > +          HC_CFG_SLV_ACT(0) | HC_CFG_MAN_CS_EN |
> > > +          HC_CFG_IDLE_SIO_LVL(1), nfc->regs + HC_CFG);
> > > +   writel(INT_STS_ALL, nfc->regs + INT_STS_EN);
> > > +   writel(0x0, nfc->regs + ONFI_DIN_CNT(0));
> > > +   writel(0, nfc->regs + LRD_CFG);
> > > +   writel(0, nfc->regs + LRD_CTRL);
> > > +   writel(0x0, nfc->regs + HC_EN);
> > > +
> > > +   /* Default 10 MHz to setup tRC_min/tWC_min:100 ns */
> > > +   mxic_nfc_set_freq(nfc, 10000000);
> > > +}
> > > +
> > > +static void mxic_nfc_cs_enable(struct mxic_nand_ctlr *nfc)
> > > +{
> > > +   writel(readl(nfc->regs + HC_CFG) | HC_CFG_MAN_CS_EN,
> > > +          nfc->regs + HC_CFG);
> > > +   writel(HC_CFG_MAN_CS_ASSERT | readl(nfc->regs + HC_CFG),
> > > +          nfc->regs + HC_CFG);  
> > 
> > So you can drive only one CS with this controller?  
> 
> yes,
> 
> >   
> > > +}
> > > +
> > > +static void mxic_nfc_cs_disable(struct mxic_nand_ctlr *nfc)
> > > +{
> > > +   writel(~HC_CFG_MAN_CS_ASSERT & readl(nfc->regs + HC_CFG),
> > > +          nfc->regs + HC_CFG);
> > > +}
> > > +
> > > +static int  mxic_nfc_wait_ready(struct nand_chip *chip)
> > > +{
> > > +   struct mxic_nand_ctlr *nfc = nand_get_controller_data(chip);
> > > +   u32 sts;
> > > +
> > > +   return readl_poll_timeout(nfc->regs + INT_STS, sts,
> > > +              sts & INT_RDY_PIN, 0, USEC_PER_SEC);
> > > +}
> > > +
> > > +static int mxic_nfc_data_xfer(struct mxic_nand_ctlr *nfc, const void   
> *txbuf,
> > > +               void *rxbuf, unsigned int len)
> > > +{
> > > +   unsigned int pos = 0;
> > > +
> > > +   while (pos < len) {
> > > +      unsigned int nbytes = len - pos;
> > > +      u32 data = 0xffffffff;
> > > +      u32 sts;
> > > +      int ret;
> > > +
> > > +      if (nbytes > 4)
> > > +         nbytes = 4;
> > > +
> > > +      if (txbuf)
> > > +         memcpy(&data, txbuf + pos, nbytes);
> > > +
> > > +      ret = readl_poll_timeout(nfc->regs + INT_STS, sts,
> > > +                sts & INT_TX_EMPTY, 0, USEC_PER_SEC);
> > > +      if (ret)
> > > +         return ret;
> > > +
> > > +      writel(data, nfc->regs + TXD(nbytes % 4));
> > > +
> > > +      if (rxbuf) {
> > > +         ret = readl_poll_timeout(nfc->regs + INT_STS, sts,
> > > +                   sts & INT_TX_EMPTY, 0,
> > > +                   USEC_PER_SEC);
> > > +         if (ret)
> > > +            return ret;
> > > +
> > > +         ret = readl_poll_timeout(nfc->regs + INT_STS, sts,
> > > +                   sts & INT_RX_NOT_EMPTY, 0,
> > > +                   USEC_PER_SEC);
> > > +         if (ret)
> > > +            return ret;
> > > +
> > > +         data = readl(nfc->regs + RXD);
> > > +         data >>= (8 * (4 - nbytes));
> > > +         memcpy(rxbuf + pos, &data, nbytes);
> > > +         WARN_ON(readl(nfc->regs + INT_STS) & INT_RX_NOT_EMPTY);
> > > +      } else {
> > > +         readl(nfc->regs + RXD);
> > > +      }
> > > +      WARN_ON(readl(nfc->regs + INT_STS) & INT_RX_NOT_EMPTY);  
> > 
> > WARN_ON() is maybe a bit overkill here?  
> 
> should I remove it ?

I would stick to regular dev_warn.


Thanks,
Miquèl

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