Messages in this thread | | | From | Andy Shevchenko <> | Date | Thu, 6 Jan 2022 20:19:39 +0200 | Subject | Re: [PATCH v6 3/3] mmc: Add driver for LiteX's LiteSDCard interface |
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On Thu, Jan 6, 2022 at 7:48 PM Gabriel Somlo <gsomlo@gmail.com> wrote: > > LiteX (https://github.com/enjoy-digital/litex) is a SoC framework > that targets FPGAs. LiteSDCard is a small footprint, configurable > SDCard core commonly used in LiteX designs. > > The driver was first written in May 2020 and has been maintained > cooperatively by the LiteX community. Thanks to all contributors!
> +config MMC_LITEX > + tristate "LiteX MMC Host Controller support" > + depends on OF > + depends on PPC_MICROWATT || LITEX || COMPILE_TEST > + help > + This selects support for the MMC Host Controller found in LiteX SoCs. > + > + If unsure, say N.
What would be the module name if built as a module?
...
> +/* > + * LiteX LiteSDCard driver > + * > + * Copyright (C) 2019-2020 Antmicro <contact@antmicro.com> > + * Copyright (C) 2019-2020 Kamil Rakoczy <krakoczy@antmicro.com> > + * Copyright (C) 2019-2020 Maciej Dudek <mdudek@internships.antmicro.com> > + * Copyright (C) 2020 Paul Mackerras <paulus@ozlabs.org> > + * Copyright (C) 2020-2021 Gabriel Somlo <gsomlo@gmail.com>
> + *
Redundant blank line.
> + */
...
> +#include <linux/module.h> > +#include <linux/litex.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > +#include <linux/clk.h> > +#include <linux/interrupt.h> > +#include <linux/iopoll.h> > +#include <linux/mmc/sd.h> > +#include <linux/mmc/mmc.h> > +#include <linux/mmc/host.h> > +#include <linux/delay.h> > +#include <linux/dma-mapping.h>
Perhaps keep it sorted? It will easily show, for example, absence of bits.h.
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> + ret = readx_poll_timeout(litex_read8, reg, evt, (evt & SD_BIT_DONE),
Too many parentheses.
> + SD_SLEEP_US, SD_TIMEOUT_US);
> + if (ret || (evt & SD_BIT_TIMEOUT))
Redundant second condition. If you want +1 iteration, increase timeout.
> + return -ETIMEDOUT;
Why shadowed error code?
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> + pr_err("%s: unknown error evt=%x\n", __func__, evt);
Use dev_err().
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> + /* Wait for an interrupt if we have an interrupt and either there is > + * data to be transferred, or if the card can report busy via DAT0. > + */
This comment style is for the net subsystem, for others we use /* * Starting here... */
Fix it everywhere in your code.
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> + reg = host->sdcore + LITEX_CORE_CMDRSP; > + for (i = 0; i < 4; i++) { > + host->resp[i] = litex_read32(reg); > + reg += sizeof(u32); > + }
Isn't it memcpy_fromio()?
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> + if (!host->app_cmd && cmd == SD_SEND_RELATIVE_ADDR) > + host->rca = (host->resp[3] >> 16) & 0xffff;
Are you expecting a 32-bit value to be bigger than 2^32-1?
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> + div = min(max(div, 2U), 256U);
clamp_t() / clamp_val() ?
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> + ret = platform_get_irq_optional(host->dev, 0); > + if (ret == -ENXIO || ret == 0) { > + dev_warn(dev, "Failed to get IRQ, using polling\n"); > + goto use_polling; > + } > + if (ret < 0) > + return ret; /* e.g., deferred probe */ > + host->irq = ret;
Can it be rather written as
ret = platform_get_irq_optional(host->dev, 0); if (ret < 0 && ret != -ENXIO) return ret; if (ret > 0) host->irq = ret; else { dev_warn(dev, "Failed to get IRQ, using polling\n"); goto use_polling; }
?
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> +use_polling: > + host->mmc->caps |= MMC_CAP_NEEDS_POLL;
> + host->irq = 0;
Isn't it 0 by default?
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> + mmc = mmc_alloc_host(sizeof(struct litex_mmc_host), &pdev->dev);
> + /* NOTE: defaults to max_[req,seg]_size=PAGE_SIZE, max_blk_size=512, > + * and max_blk_count accordingly set to 8; > + * If for some reason we need to modify max_blk_count, we must also > + * re-calculate `max_[req,seg]_size = max_blk_size * max_blk_count;` > + */
Can you rather not split code by this comment. It makes sense to be above, no?
> + if (!mmc) > + return -ENOMEM;
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> + /* set default sd_clk frequency range based on empirical observations > + * of LiteSDCard gateware behavior on typical SDCard media > + */
Start sentences from capital letters and keep proper style of multi-line comments.
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> +err: > + mmc_free_host(mmc); > + return ret;
This...
> +} > + > +static int litex_mmc_remove(struct platform_device *pdev) > +{ > + struct litex_mmc_host *host = dev_get_drvdata(&pdev->dev); > + > + if (host->irq > 0) > + free_irq(host->irq, host->mmc); > + mmc_remove_host(host->mmc); > + mmc_free_host(host->mmc);
...and this have ordering issues. You mixed devm_*() with non-devm_*() APIs in the wrong way.
Also, I haven't noticed the free_irq() call in the error path of ->probe(). Isn't it missed?
> + return 0; > +}
...
> + .of_match_table = of_match_ptr(litex_match),
Wrong usage of of_match_ptr().
-- With Best Regards, Andy Shevchenko
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