[PATCH v2 01/10] spi: dw: Convert calls to debug to log_*

Sean Anderson
2020-08-08T11:07:35Z

On 8/8/20 1:14 AM, Heinrich Schuchardt wrote:
> On 8/7/20 4:43 PM, Sean Anderson wrote:
>> This allows different log levels to be enabled or disabled depending on the
>> desired level of verbosity. In particular, it allows for general debug
>> information to be printed while excluding more verbose logging which may
>> interfere with timing.
>>
>> Signed-off-by: Sean Anderson <seanga2@gmail.com>
>> ---/
>>
>> Changes in v2:
>> - New
>>
>> drivers/spi/designware_spi.c | 33 ++++++++++++++++-----------------
>> 1 file changed, 16 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c
>> index c9b14f9029..f7ea3edaab 100644
>> --- a/drivers/spi/designware_spi.c
>> +++ b/drivers/spi/designware_spi.c
>> @@ -9,6 +9,7 @@
>> * Copyright (c) 2009, Intel Corporation.
>> */
>>
>> +#define LOG_CATEGORY UCLASS_SPI
>> #include <common.h>
>> #include <log.h>
>> #include <asm-generic/gpio.h>
>> @@ -139,7 +140,7 @@ static int request_gpio_cs(struct udevice *bus)
>> return 0;
>>
>> if (ret < 0) {
>> - printf("Error: %d: Can't get %s gpio!\n", ret, bus->name);
>> + log_err("Error: %d: Can't get %s gpio!\n", ret, bus->name);
>
> Thanks for caring to convert this to the more flexible logging.

It was quite difficult to debug without these changes, since turning on
debug statements caused the fifos to over/underflow.

>
> Error: -23: Can't get spi at 53000000 gpio!
>
> Shouldn't we remove one colon:
>
> Error -23: Can't get spi at 53000000 gpio!

Sure.

>> return ret;
>> }
>>
>> @@ -148,7 +149,7 @@ static int request_gpio_cs(struct udevice *bus)
>> GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
>> }
>>
>> - debug("%s: used external gpio for CS management\n", __func__);
>> + log_info("Using external gpio for CS management\n");
>
> On systems with CONFIG_LOG=n log_info() messages are always printed. By
> default the function name is not printed in log messages.
>
> Showing this message to the end-user of the device on every boot
> provides no benefit.
>
> log_debug() seems more adequate.

Ok. I was generally unsure what log level to default to. README.log
doesn't really make it clear semantically which log levels should be
used.

>> #endif
>> return 0;
>> }
>> @@ -162,8 +163,7 @@ static int dw_spi_ofdata_to_platdata(struct udevice *bus)
>> /* Use 500KHz as a suitable default */
>> plat->frequency = dev_read_u32_default(bus, "spi-max-frequency",
>> 500000);
>> - debug("%s: regs=%p max-frequency=%d\n", __func__, plat->regs,
>> - plat->frequency);
>> + log_info("regs=%p max-frequency=%d\n", plat->regs, plat->frequency);
>
> The output will look like this:
>
> regs=0x1234 max-frequency=2000000
>
> Such a message appearing on every boot will be irritating for end-users.
>
> Please, use log_debug() here.

Ok.

> Can we replace 'regs=' by 'SPI@' for all messages?

Sure.

>>
>> return request_gpio_cs(bus);
>> }
>> @@ -196,7 +196,7 @@ static void spi_hw_init(struct dw_spi_priv *priv)
>> priv->fifo_len = (fifo == 1) ? 0 : fifo;
>> dw_write(priv, DW_SPI_TXFLTR, 0);
>> }
>> - debug("%s: fifo_len=%d\n", __func__, priv->fifo_len);
>> + log_debug("fifo_len=%d\n", priv->fifo_len);
>> }
>>
>> /*
>> @@ -221,8 +221,7 @@ __weak int dw_spi_get_clk(struct udevice *bus, ulong *rate)
>> if (!*rate)
>> goto err_rate;
>>
>> - debug("%s: get spi controller clk via device tree: %lu Hz\n",
>> - __func__, *rate);
>> + log_debug("Got spi controller clk via device tree: %lu Hz\n", *rate);
>
> %s/spi/SPI/

Ok.

>>
>> return 0;
>>
>> @@ -247,14 +246,14 @@ static int dw_spi_reset(struct udevice *bus)
>> if (ret == -ENOENT || ret == -ENOTSUPP)
>> return 0;
>>
>> - dev_warn(bus, "Can't get reset: %d\n", ret);
>> + log_warning("Can't get reset: %d\n", ret);
>
> This message does not tell me that there is a problem with SPI. Please,
> provide a useful text.

Perhaps "Couldn't find or assert reset device configured for SPI"?

>> return ret;
>> }
>>
>> ret = reset_deassert_bulk(&priv->resets);
>> if (ret) {
>> reset_release_bulk(&priv->resets);
>> - dev_err(bus, "Failed to reset: %d\n", ret);
>> + log_err("Failed to reset: %d\n", ret);
>
> What shall I do when reading a message like:
>
> "Failed to reset: -23".
>
> Please, provide a more informative text.

Perhaps "SPI: failed to deassert reset (error %d)"?

>> return ret;
>> }
>>
>> @@ -333,7 +332,7 @@ static void dw_writer(struct dw_spi_priv *priv)
>> txw = *(u16 *)(priv->tx);
>> }
>> dw_write(priv, DW_SPI_DR, txw);
>> - debug("%s: tx=0x%02x\n", __func__, txw);
>> + log_content("tx=0x%02x\n", txw);
>> priv->tx += priv->bits_per_word >> 3;
>> }
>> }
>> @@ -345,7 +344,7 @@ static void dw_reader(struct dw_spi_priv *priv)
>>
>> while (max--) {
>> rxw = dw_read(priv, DW_SPI_DR);
>> - debug("%s: rx=0x%02x\n", __func__, rxw);
>> + log_content("rx=0x%02x\n", rxw);
>>
>> /* Care about rx if the transfer's original "rx" is not null */
>> if (priv->rx_end - priv->len) {
>> @@ -400,7 +399,7 @@ static int dw_spi_xfer(struct udevice *dev, unsigned int bitlen,
>>
>> /* spi core configured to do 8 bit transfers */
>> if (bitlen % 8) {
>> - debug("Non byte aligned SPI transfer.\n");
>> + log_err("Non byte aligned SPI transfer.\n");
>> return -1;
>> }
>>
>> @@ -427,7 +426,7 @@ static int dw_spi_xfer(struct udevice *dev, unsigned int bitlen,
>> cr0 |= (priv->tmode << SPI_TMOD_OFFSET);
>>
>> priv->len = bitlen >> 3;
>> - debug("%s: rx=%p tx=%p len=%d [bytes]\n", __func__, rx, tx, priv->len);
>> + log_debug("rx=%p tx=%p len=%d [bytes]\n", rx, tx, priv->len);
>
> Please, use log_debug_io() here.

When should log_content/log_io be used? Here, we only log metadata about
the transfer. I would expect this to be a higher log level than (for
example) the actual log of the content as done in dw_reader/writer. In
addition, I am confused as to when log_io should be used over
log_content. The only clear-cut case I can see is perhaps that replacing
dw_write with something like

static inline void dw_write(struct dw_spi_priv *priv, u32 offset, u32 val)
{
log_io("%x = %x", offset, val);
__raw_writel(val, priv->regs + offset);
}

Is log_content intended for higher-level interfaces?

>>
>> priv->tx = (void *)tx;
>> priv->tx_end = priv->tx + priv->len;
>> @@ -437,7 +436,7 @@ static int dw_spi_xfer(struct udevice *dev, unsigned int bitlen,
>> /* Disable controller before writing control registers */
>> spi_enable_chip(priv, 0);
>>
>> - debug("%s: cr0=%08x\n", __func__, cr0);
>> + log_debug("cr0=%08x\n", cr0);
>
> log_debug_io()

Same comments/questions as above.

--Sean