Re: [PATCH v2 1/2] spi: Add Renesas R-Car Gen3 RPC SPI controller driver

From: Sergei Shtylyov
Date: Fri Dec 07 2018 - 13:18:11 EST

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In reply to: Marek Vasut: "Re: [PATCH v2 1/2] spi: Add Renesas R-Car Gen3 RPC SPI controller driver"
Next in thread: Marek Vasut: "Re: [PATCH v2 1/2] spi: Add Renesas R-Car Gen3 RPC SPI controller driver"
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Hello!

I'd already started the v2 driver review before you posted v3, so here goes...

On 12/03/2018 12:18 PM, Mason Yang wrote:

> Add a driver for Renesas R-Car Gen3 RPC SPI controller.
>
> Signed-off-by: Mason Yang <masonccyang@xxxxxxxxxxx>
[...]
> diff --git a/drivers/spi/spi-renesas-rpc.c b/drivers/spi/spi-renesas-rpc.c
> new file mode 100644
> index 0000000..ac9094e
> --- /dev/null
> +++ b/drivers/spi/spi-renesas-rpc.c
> @@ -0,0 +1,808 @@
[...]
> +#define RPC_CMNCR 0x0000 /* R/W */
> +#define RPC_CMNCR_MD BIT(31)
> +#define RPC_CMNCR_SFDE BIT(24)

This bit is undocumented as of the gen3 manual v1.0. I'd like this to be reflected
in a comment...

[...]
> +#define RPC_CMNCR_IO3FV(val) (((val) & 0x3) << 14)
> +#define RPC_CMNCR_IO2FV(val) (((val) & 0x3) << 12)

These 2 are also undocumented.

[...]
> +#define RPC_CMNCR_CPHAT BIT(6)
> +#define RPC_CMNCR_CPHAR BIT(5)
> +#define RPC_CMNCR_SSLP BIT(4)
> +#define RPC_CMNCR_CPOL BIT(3)

And these 4...

> +#define RPC_DRCR 0x000C /* R/W */
> +#define RPC_DRCR_SSLN BIT(24)
> +#define RPC_DRCR_RBURST(v) (((v) & 0x1F) << 16)

More like ((v) - 1), like in another register...

> +#define RPC_DRCR_RCF BIT(9)
> +#define RPC_DRCR_RBE BIT(8)
> +#define RPC_DRCR_SSLE BIT(0)
[...]
> +#define RPC_DREAR 0x0014 /* R/W */
> +#define RPC_DREAR_EAC BIT(0)

The manual says it takes bits 0 to 2...

[...]
> +#define RPC_SMADR 0x0028 /* R/W */
> +#define RPC_SMOPR 0x002C /* R/W */
> +#define RPC_SMOPR_OPD0(o) (((o) & 0xFF) << 0)
> +#define RPC_SMOPR_OPD1(o) (((o) & 0xFF) << 8)
> +#define RPC_SMOPR_OPD2(o) (((o) & 0xFF) << 16)
> +#define RPC_SMOPR_OPD3(o) (((o) & 0xFF) << 24)

You either go in descending or ascending order, not both. :-)

[...]
> +#define RPC_PHYCNT 0x007C /* R/W */
> +#define RPC_PHYCNT_CAL BIT(31)
> +#define PRC_PHYCNT_OCTA_AA BIT(22)
> +#define PRC_PHYCNT_OCTA_SA BIT(23)
> +#define PRC_PHYCNT_EXDS BIT(21)
> +#define RPC_PHYCNT_OCT BIT(20)
> +#define RPC_PHYCNT_STRTIM(v) (((v) & 0x7) << 15)
> +#define RPC_PHYCNT_WBUF2 BIT(4)
> +#define RPC_PHYCNT_WBUF BIT(2)
> +#define RPC_PHYCNT_MEM(v) (((v) & 0x3) << 0)

The manual calls this field PHYMEM...

[...]
> +#define LOOP_TIMEOUT 1024

It's more like TIMEOUT_LOOPS. :-)

[...]
> +static void rpc_spi_hw_init(struct rpc_spi *rpc)
> +{
> + /*
> + * NOTE: The 0x260 are undocumented bits, but they must be set.
> + * RPC_PHYCNT_STRTIM is strobe timing adjustment bit,
> + * 0x0 : the delay is biggest,
> + * 0x1 : the delay is 2nd biggest,
> + * 0x3 or 0x6 is a recommended value.
> + */
> + regmap_write(rpc->regmap, RPC_PHYCNT, RPC_PHYCNT_CAL |
> + RPC_PHYCNT_STRTIM(0x6) | 0x260);
> +
> + /*
> + * NOTE: The 0x31511144 and 0x431 are undocumented bits,
> + * but they must be set for RPC_PHYOFFSET1 & RPC_PHYOFFSET2.
> + */
> + regmap_write(rpc->regmap, RPC_PHYOFFSET1, 0x31511144);
> + regmap_write(rpc->regmap, RPC_PHYOFFSET2, 0x431);

0x400 is actually documented, bits 0..7 are read only and default to 0x31...

> +#ifdef CONFIG_RESET_CONTROLLER
> +static int rpc_spi_do_reset(struct rpc_spi *rpc)
> +{
> + int i, ret;
> +
> + ret = reset_control_reset(rpc->rstc);
> + if (ret)
> + return ret;
> +
> + for (i = 0; i < LOOP_TIMEOUT; i++) {
> + ret = reset_control_status(rpc->rstc);
> + if (ret == 0)
> + return 0;
> + usleep_range(0, 1);

Are you serious? :-)

> + }
> +
> + return -ETIMEDOUT;
> +}
> +#else
> +static int rpc_spi_do_reset(struct rpc_spi *rpc)
> +{
> + return -ETIMEDOUT;
> +}
> +#endif
[...]
> +static int rpc_spi_io_xfer(struct rpc_spi *rpc,
> + const void *tx_buf, void *rx_buf)
> +{
> + u32 smenr, smcr, data, pos = 0;
> + int ret = 0;
> +
> + regmap_write(rpc->regmap, RPC_CMNCR, RPC_CMNCR_MD | RPC_CMNCR_SFDE |
> + RPC_CMNCR_MOIIO_HIZ | RPC_CMNCR_IOFV_HIZ |
> + RPC_CMNCR_BSZ(0));
> + regmap_write(rpc->regmap, RPC_SMDRENR, 0x0);

Just 0, please.

> + regmap_write(rpc->regmap, RPC_SMCMR, rpc->cmd);
> + regmap_write(rpc->regmap, RPC_SMDMCR, rpc->dummy);
> + regmap_write(rpc->regmap, RPC_SMADR, rpc->addr);
> +
> + if (tx_buf) {
> + smenr = rpc->smenr;
> +
> + while (pos < rpc->xferlen) {
> + u32 nbytes = rpc->xferlen - pos;

One space before '-' is enough. :-)

> +
> + regmap_write(rpc->regmap, RPC_SMWDR0,
> + *(u32 *)(tx_buf + pos));

Ugh... what about the data endianness?

> +
> + if (nbytes > 4) {
> + nbytes = 4;
> + smcr = rpc->smcr |
> + RPC_SMCR_SPIE | RPC_SMCR_SSLKP;
> + } else {
> + smcr = rpc->smcr | RPC_SMCR_SPIE;
> + }

Please do this repeated part outside *if*:

smcr = rpc->smcr | RPC_SMCR_SPIE;
if (nbytes > 4) {
nbytes = 4;
smcr |= RPC_SMCR_SSLKP;
}

[...]
> + } else if (rx_buf) {
> + while (pos < rpc->xferlen) {
> + u32 nbytes = rpc->xferlen - pos;

Again, 1 space is enough...

> +
> + if (nbytes > 4)
> + nbytes = 4;
> +
> + regmap_write(rpc->regmap, RPC_SMENR, rpc->smenr);
> + regmap_write(rpc->regmap, RPC_SMCR,
> + rpc->smcr | RPC_SMCR_SPIE);
> + ret = wait_msg_xfer_end(rpc);
> + if (ret)
> + goto out;
> +
> + regmap_read(rpc->regmap, RPC_SMRDR0, &data);
> + memcpy_fromio(rx_buf + pos, (void *)&data, nbytes);

What?! The 'data' variable is not in a MMIO region, you can use plain memcpy().
Not sure about the endianness tho...

[...]
> + } else {
> + regmap_write(rpc->regmap, RPC_SMENR, rpc->smenr);
> + regmap_write(rpc->regmap, RPC_SMCR, rpc->smcr | RPC_SMCR_SPIE);

Er... what's this for?

> + ret = wait_msg_xfer_end(rpc);
> + if (ret)
> + goto out;
> + }
> +
> + return ret;

Need empty line here...

> +out:
> + return rpc_spi_do_reset(rpc);
> +}
> +
> +static void rpc_spi_mem_set_prep_op_cfg(struct spi_device *spi,
> + const struct spi_mem_op *op,
> + u64 *offs, size_t *len)
> +{
> + struct rpc_spi *rpc = spi_master_get_devdata(spi->master);
> +
> + rpc->cmd = RPC_SMCMR_CMD(op->cmd.opcode);
> + rpc->smenr = RPC_SMENR_CDE |
> + RPC_SMENR_CDB(fls(op->cmd.buswidth >> 1));

Maybe ilog2()?

> + rpc->totalxferlen = 1;
> + rpc->xfer_dir = SPI_MEM_NO_DATA;
> + rpc->xferlen = 0;
> + rpc->addr = 0;
> +
> + if (op->addr.nbytes) {
> + rpc->smenr |= RPC_SMENR_ADB(fls(op->addr.buswidth >> 1));

Again, ilog2()?

[...]
> + if (op->data.nbytes || (offs && len)) {
> + if (op->data.dir == SPI_MEM_DATA_IN) {
> + rpc->smcr = RPC_SMCR_SPIRE;
> + rpc->xfer_dir = SPI_MEM_DATA_IN;
> + } else if (op->data.dir == SPI_MEM_DATA_OUT) {
> + rpc->smcr = RPC_SMCR_SPIWE;
> + rpc->xfer_dir = SPI_MEM_DATA_OUT;
> + }

This code is asking for using *switch*...

> +
> + if (offs && len) {
> + rpc->smenr |= RPC_SMENR_SPIDE(rpc_bits_xfer
> + (*(u32 *)len)) | RPC_SMENR_SPIDB

Unobvious line breaks...

> + (fls(op->data.buswidth >> 1));

ilog2()?

> +
> + rpc->xferlen = *(u32 *)len;
> + rpc->totalxferlen += *(u32 *)len;
> + } else {
> + rpc->smenr |= RPC_SMENR_SPIDE(rpc_bits_xfer
> + (op->data.nbytes)) | RPC_SMENR_SPIDB
> + (fls(op->data.buswidth >> 1));

You can factor out a large part of this expression and calculate it before *if*...

> +
> + rpc->xferlen = op->data.nbytes;
> + rpc->totalxferlen += op->data.nbytes;
> + }
> + }
> +}
> +
> +static bool rpc_spi_mem_supports_op(struct spi_mem *mem,
> + const struct spi_mem_op *op)
> +{
> + if (op->data.buswidth > 4 || op->addr.buswidth > 4 ||
> + op->dummy.buswidth > 4 || op->cmd.buswidth > 4)

Hm, the manual doesn't mention 2-wire SPI mode...

> + return false;
> +
> + if (op->addr.nbytes > 4)
> + return false;
> +
> + return true;
> +}
> +
> +static ssize_t rpc_spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc,
> + u64 offs, size_t len, void *buf)
> +{
> + struct rpc_spi *rpc = spi_master_get_devdata(desc->mem->spi->master);
> + int ret;
> +
> + if (WARN_ON(offs + desc->info.offset + len > U32_MAX))
> + return -EINVAL;
> +
> + ret = rpc_spi_set_freq(rpc, desc->mem->spi->max_speed_hz);
> + if (ret)
> + return ret;
> +
> + rpc_spi_mem_set_prep_op_cfg(desc->mem->spi,
> + &desc->info.op_tmpl, &offs, &len);
> +
> + regmap_write(rpc->regmap, RPC_CMNCR, RPC_CMNCR_SFDE |
> + RPC_CMNCR_MOIIO_HIZ | RPC_CMNCR_IOFV_HIZ |
> + RPC_CMNCR_BSZ(0));
> + regmap_write(rpc->regmap, RPC_DRCR, RPC_DRCR_RBURST(0x1f) |

RPC_DRCR_RBURST(32), please.

> + RPC_DRCR_RBE);
> + regmap_write(rpc->regmap, RPC_DRCMR, rpc->cmd);
> + regmap_write(rpc->regmap, RPC_DREAR, RPC_DREAR_EAC);
> + regmap_write(rpc->regmap, RPC_DROPR, 0);
> + regmap_write(rpc->regmap, RPC_DRENR, rpc->smenr);

Looks liky you need a more generic field name (like rpc->cmd)...

> + regmap_write(rpc->regmap, RPC_DRDMCR, rpc->dummy);
> + regmap_write(rpc->regmap, RPC_DRDRENR, 0);
> +
> + memcpy_fromio(buf, rpc->linear.map + desc->info.offset + offs, len);

What if the read direct-mapped area is less than U32_MAX in size (and it will be,
according to your bindings)?

> +
> + return len;
> +}
> +
> +static ssize_t rpc_spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc,
> + u64 offs, size_t len, const void *buf)
> +{
> + struct rpc_spi *rpc = spi_master_get_devdata(desc->mem->spi->master);
> + int ret;
> +
> + if (WARN_ON(offs + desc->info.offset + len > U32_MAX))
> + return -EINVAL;
> +
> + if (WARN_ON(len > RPC_WBUF_SIZE))
> + return -EIO;

Why not write 256 bytes and return w/that?

> +
> + ret = rpc_spi_set_freq(rpc, desc->mem->spi->max_speed_hz);
> + if (ret)
> + return ret;
> +
> + rpc_spi_mem_set_prep_op_cfg(desc->mem->spi,
> + &desc->info.op_tmpl, &offs, &len);
> +
> + regmap_write(rpc->regmap, RPC_CMNCR, RPC_CMNCR_MD | RPC_CMNCR_SFDE |
> + RPC_CMNCR_MOIIO_HIZ | RPC_CMNCR_IOFV_HIZ |
> + RPC_CMNCR_BSZ(0));
> + regmap_write(rpc->regmap, RPC_SMDRENR, 0);
> + regmap_write(rpc->regmap, RPC_PHYCNT, RPC_PHYCNT_CAL | 0x260 |
> + RPC_PHYCNT_WBUF2 | RPC_PHYCNT_WBUF);

Didn't understand this 2-write-buffers thing...

> +
> + memcpy_toio(rpc->base + RPC_WBUF, buf, len);
> +
> + regmap_write(rpc->regmap, RPC_SMCMR, rpc->cmd);
> + regmap_write(rpc->regmap, RPC_SMADR, offs);
> + regmap_write(rpc->regmap, RPC_SMENR, rpc->smenr);
> + regmap_write(rpc->regmap, RPC_SMCR, rpc->smcr | RPC_SMCR_SPIE);
> + ret = wait_msg_xfer_end(rpc);
> + if (ret)
> + goto out;
> +
> + regmap_write(rpc->regmap, RPC_DRCR, RPC_DRCR_RCF);
> + regmap_write(rpc->regmap, RPC_PHYCNT, RPC_PHYCNT_CAL |
> + RPC_PHYCNT_STRTIM(6) | 0x260);
> +
> + return len;

Need empty line here.

> +out:
> + return rpc_spi_do_reset(rpc);
> +}
[...]> +static void rpc_spi_transfer_setup(struct rpc_spi *rpc,
> + struct spi_message *msg)
> +{
> + struct spi_transfer *t, xfer[4] = { };
> + u32 i, xfercnt, xferpos = 0;
> +
> + rpc->totalxferlen = 0;
> + rpc->xfer_dir = SPI_MEM_NO_DATA;
> +
> + list_for_each_entry(t, &msg->transfers, transfer_list) {
> + if (t->tx_buf) {
> + xfer[xferpos].tx_buf = t->tx_buf;
> + xfer[xferpos].tx_nbits = t->tx_nbits;
> + }
> +
> + if (t->rx_buf) {
> + xfer[xferpos].rx_buf = t->rx_buf;
> + xfer[xferpos].rx_nbits = t->rx_nbits;
> + }
> +
> + if (t->len) {
> + xfer[xferpos++].len = t->len;
> + rpc->totalxferlen += t->len;
> + }
> +
> + if (list_is_last(&t->transfer_list, &msg->transfers)) {
> + if (xferpos > 1 && t->rx_buf) {
> + rpc->xfer_dir = SPI_MEM_DATA_IN;
> + rpc->smcr = RPC_SMCR_SPIRE;
> + } else if (xferpos > 1 && t->tx_buf) {

Why check 'xferpos' twice?

> + rpc->xfer_dir = SPI_MEM_DATA_OUT;
> + rpc->smcr = RPC_SMCR_SPIWE;
> + }
> + }
> + }
> +
> + xfercnt = xferpos;
> + rpc->xferlen = xfer[--xferpos].len;
> + rpc->cmd = RPC_SMCMR_CMD(((u8 *)xfer[0].tx_buf)[0]);
> + rpc->smenr = RPC_SMENR_CDE | RPC_SMENR_CDB(fls(xfer[0].tx_nbits >> 1));

ilog2()?

> + rpc->addr = 0;
> +
> + if (xfercnt > 2 && xfer[1].len && xfer[1].tx_buf) {
> + rpc->smenr |= RPC_SMENR_ADB(fls(xfer[1].tx_nbits >> 1));

ilog2()?

> + for (i = 0; i < xfer[1].len; i++)
> + rpc->addr |= (u32)((u8 *)xfer[1].tx_buf)[i]
> + << (8 * (xfer[1].len - i - 1));

Ugh, you need get_unaligned_*()...

> +
> + if (xfer[1].len == 4)
> + rpc->smenr |= RPC_SMENR_ADE(0xf);
> + else
> + rpc->smenr |= RPC_SMENR_ADE(0x7);
> + }
> +
> + switch (xfercnt) {
> + case 2:
> + if (xfer[1].rx_buf) {
> + rpc->smenr |= RPC_SMENR_SPIDE(rpc_bits_xfer
> + (xfer[1].len)) | RPC_SMENR_SPIDB(fls
> + (xfer[1].rx_nbits >> 1));
> + } else if (xfer[1].tx_buf) {
> + rpc->smenr |= RPC_SMENR_SPIDE(rpc_bits_xfer
> + (xfer[1].len)) | RPC_SMENR_SPIDB(fls
> + (xfer[1].tx_nbits >> 1));
> + }
> + break;
> +
> + case 3:
> + if (xfer[2].len && xfer[2].rx_buf && !xfer[2].tx_buf) {
> + rpc->smenr |= RPC_SMENR_SPIDE(rpc_bits_xfer
> + (xfer[2].len)) | RPC_SMENR_SPIDB(fls
> + (xfer[2].rx_nbits >> 1));
> + } else if (xfer[2].len && xfer[2].tx_buf && !xfer[2].rx_buf) {
> + rpc->smenr |= RPC_SMENR_SPIDE(rpc_bits_xfer
> + (xfer[2].len)) | RPC_SMENR_SPIDB(fls
> + (xfer[2].tx_nbits >> 1));
> + }
> + break;
> +
> + case 4:
> + if (xfer[2].len && xfer[2].tx_buf) {
> + rpc->smenr |= RPC_SMENR_DME;
> + rpc->dummy = RPC_SMDMCR_DMCYC(xfer[2].len);
> + }
> +
> + if (xfer[3].len && xfer[3].rx_buf) {
> + rpc->smenr |= RPC_SMENR_SPIDE(rpc_bits_xfer
> + (xfer[3].len)) | RPC_SMENR_SPIDB(fls
> + (xfer[3].rx_nbits >> 1));
> + }
> + break;
> +
> + default:
> + break;

Ugh... don't want to repeat after Marek. :-)

[...]
> +static const struct regmap_config rpc_spi_regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> + .fast_io = true,
> + .max_register = RPC_WBUF + RPC_WBUF_SIZE,

Ugh... 0x8100/4 regs, of which the majority isn't used... :-/

> + .volatile_table = &rpc_spi_volatile_table,
> +};
> +
> +static int rpc_spi_probe(struct platform_device *pdev)
> +{
> + struct spi_master *master;
> + struct resource *res;
> + struct rpc_spi *rpc;
> + const struct regmap_config *regmap_config;
> + int ret;
[...]
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rpc_regs");

I'd suggest just "regs".

> + rpc->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(rpc->base))
> + return PTR_ERR(rpc->base);
[...]
> +err_put_master:
> + spi_master_put(master);
> + pm_runtime_disable(&pdev->dev);
> +
> + return ret;
> +}
> +
> +static int rpc_spi_remove(struct platform_device *pdev)
> +{
> + struct spi_master *master = platform_get_drvdata(pdev);
> +
> + pm_runtime_disable(&pdev->dev);
> + spi_unregister_master(master);

No spi_master_put() here?

[...]

MBR, Sergei

Next message: Jethro Beekman: "Re: [RFC PATCH v2 4/4] x86/vdso: Add __vdso_sgx_enter_enclave() to wrap SGX enclave transitions"
Previous message: Paul Gortmaker: "Re: [PATCH 18/22] mfd: wm831x-i2c: Make it explicitly non-modular"
In reply to: Marek Vasut: "Re: [PATCH v2 1/2] spi: Add Renesas R-Car Gen3 RPC SPI controller driver"
Next in thread: Marek Vasut: "Re: [PATCH v2 1/2] spi: Add Renesas R-Car Gen3 RPC SPI controller driver"
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