Hi Geert, Thanks for the feedback. I've lined up most of it for v3 (which I'll send out shortly). A couple of replies inline, below: On Mon, Dec 06, 2021 at 11:07:56AM +0100, Geert Uytterhoeven wrote: > On Sat, Dec 4, 2021 at 9:41 PM Gabriel Somlo <gsomlo@xxxxxxxxx> 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! > > > > Co-developed-by: Kamil Rakoczy <krakoczy@xxxxxxxxxxxx> > > Signed-off-by: Kamil Rakoczy <krakoczy@xxxxxxxxxxxx> > > Co-developed-by: Maciej Dudek <mdudek@xxxxxxxxxxxxxxxxxxxxxxxx> > > Signed-off-by: Maciej Dudek <mdudek@xxxxxxxxxxxxxxxxxxxxxxxx> > > Co-developed-by: Paul Mackerras <paulus@xxxxxxxxxx> > > Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx> > > Signed-off-by: Gabriel Somlo <gsomlo@xxxxxxxxx> > > Thanks for your patch! > > > --- /dev/null > > +++ b/drivers/mmc/host/litex_mmc.c > > > +struct litex_mmc_host { > > + struct mmc_host *mmc; > > + struct platform_device *dev; > > + > > + void __iomem *sdphy; > > + void __iomem *sdcore; > > + void __iomem *sdreader; > > + void __iomem *sdwriter; > > + void __iomem *sdirq; > > + > > + u32 resp[4]; > > + u16 rca; > > + > > + void *buffer; > > + size_t buf_size; > > + dma_addr_t dma; > > + > > + unsigned int freq; > > + unsigned int clock; > > + bool is_bus_width_set; > > + bool app_cmd; > > + > > + int irq; > > + struct completion cmd_done; > > You may want to reorder the members to avoid implicit gaps > (i.e. structs first, followed by integral types in decreasing size). OK. > > +}; > > + > > +static int > > +sdcard_wait_done(void __iomem *reg) > > +{ > > + u8 evt; > > + int ret; > > + > > + ret = read_poll_timeout(litex_read8, evt, (evt & 0x1), > > Lots of magic numbers. Please use defines, like > > #define EVT_FOO BIT(0) Done. > > + SD_SLEEP_US, SD_TIMEOUT_US, false, reg); > > + if (ret || (evt & 0x4)) > > + return SD_TIMEOUT; > > + if (evt == 0x1) > > + return SD_OK; > > + if (evt & 0x2) > > + return SD_WRITEERROR; > > + if (evt & 0x8) > > + return SD_CRCERROR; > > + pr_err("%s: unknown error evt=%x\n", __func__, evt); > > + return SD_ERR_OTHER; > > +} > > + > > +static int > > +send_cmd(struct litex_mmc_host *host, > > + u8 cmd, u32 arg, u8 response_len, u8 transfer) > > +{ > > + void __iomem *reg; > > + u8 i; > > unsigned int OK. > > + int status; > > + > > + litex_write32(host->sdcore + LITEX_CORE_CMDARG, arg); > > + litex_write32(host->sdcore + LITEX_CORE_CMDCMD, > > + cmd << 8 | transfer << 5 | response_len); > > + litex_write8(host->sdcore + LITEX_CORE_CMDSND, 1); > > + > > + /* 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. > > + */ > > + if (host->irq > 0 && > > + (transfer != SDCARD_CTRL_DATA_TRANSFER_NONE || > > + response_len == SDCARD_CTRL_RESPONSE_SHORT_BUSY)) { > > + reinit_completion(&host->cmd_done); > > + litex_write32(host->sdirq + LITEX_IRQ_ENABLE, > > + SDIRQ_CMD_DONE | SDIRQ_CARD_DETECT); > > + wait_for_completion(&host->cmd_done); > > + } > > + > > + status = sdcard_wait_done(host->sdcore + LITEX_CORE_CMDEVT); > > + > > + if (status != SD_OK) { > > + pr_err("Command (cmd %d) failed, status %d\n", cmd, status); > > + return status; > > + } > > + > > + if (response_len != SDCARD_CTRL_RESPONSE_NONE) { > > + reg = host->sdcore + LITEX_CORE_CMDRSP; > > + for (i = 0; i < 4; i++) { > > + host->resp[i] = litex_read32(reg); > > + reg += sizeof(u32); > > + } > > + } > > + > > + if (!host->app_cmd && cmd == SD_SEND_RELATIVE_ADDR) > > + host->rca = (host->resp[3] >> 16) & 0xffff; > > + > > + host->app_cmd = (cmd == MMC_APP_CMD); > > + > > + if (transfer == SDCARD_CTRL_DATA_TRANSFER_NONE) > > + return status; /* SD_OK from prior sdcard_wait_done(cmd_evt) */ > > + > > + status = sdcard_wait_done(host->sdcore + LITEX_CORE_DATAEVT); > > + if (status != SD_OK) { > > + pr_err("Data xfer (cmd %d) failed, status %d\n", cmd, status); > > + return status; > > + } > > + > > + /* wait for completion of (read or write) DMA transfer */ > > + reg = (transfer == SDCARD_CTRL_DATA_TRANSFER_READ) ? > > + host->sdreader + LITEX_BLK2MEM_DONE : > > + host->sdwriter + LITEX_MEM2BLK_DONE; > > + > > + status = read_poll_timeout(litex_read8, i, (i & 0x1), > > + SD_SLEEP_US, SD_TIMEOUT_US, false, reg); > > + if (status) > > + pr_err("DMA timeout (cmd %d)\n", cmd); > > + > > + return status; > > +} > > + > > +static inline int > > No need for inline, the compiler can decide. OK. > > +send_app_cmd(struct litex_mmc_host *host) > > +{ > > + return send_cmd(host, MMC_APP_CMD, host->rca << 16, > > + SDCARD_CTRL_RESPONSE_SHORT, > > + SDCARD_CTRL_DATA_TRANSFER_NONE); > > +} > > + > > +static inline int > > Likewise. > > > +send_app_set_bus_width_cmd(struct litex_mmc_host *host, u32 width) > > +{ > > + return send_cmd(host, SD_APP_SET_BUS_WIDTH, width, > > + SDCARD_CTRL_RESPONSE_SHORT, > > + SDCARD_CTRL_DATA_TRANSFER_NONE); > > +} > > > +static int > > +litex_get_cd(struct mmc_host *mmc) > > litex_mmc_get_cd()? (i.e. "litex_mmc_"-prefix everywhere) Done, throughout the entire file. > > +{ > > + struct litex_mmc_host *host = mmc_priv(mmc); > > + int ret; > > + > > + if (!mmc_card_is_removable(mmc)) > > + return 1; > > + > > + ret = mmc_gpio_get_cd(mmc); > > + if (ret >= 0) > > + /* GPIO based card-detect explicitly specified in DTS */ > > + ret = !!ret; > > + else > > + /* use gateware card-detect bit by default */ > > + ret = !litex_read8(host->sdphy + LITEX_PHY_CARDDETECT); > > Please use curly braces to delimit blocks larger than a single line. OK. > > + > > + /* ensure bus width will be set (again) upon card (re)insertion */ > > + if (ret == 0) > > + host->is_bus_width_set = false; > > + > > + return ret; > > +} > > > +static u32 > > +litex_response_len(struct mmc_command *cmd) > > +{ > > + if (cmd->flags & MMC_RSP_136) { > > + return SDCARD_CTRL_RESPONSE_LONG; > > + } else if (cmd->flags & MMC_RSP_PRESENT) { > > No need for else after return. > > > + if (cmd->flags & MMC_RSP_BUSY) > > + return SDCARD_CTRL_RESPONSE_SHORT_BUSY; > > + else > > + return SDCARD_CTRL_RESPONSE_SHORT; > > + } > > + return SDCARD_CTRL_RESPONSE_NONE; > > Perhaps it's worthwhile to invert the logic of the last check, to > reduce indentation? > > if (cmd->flags & MMC_RSP_136) > return SDCARD_CTRL_RESPONSE_LONG; > > if (!(cmd->flags & MMC_RSP_PRESENT)) > return SDCARD_CTRL_RESPONSE_NONE; > > if (cmd->flags & MMC_RSP_BUSY) > return SDCARD_CTRL_RESPONSE_SHORT_BUSY; > > return SDCARD_CTRL_RESPONSE_SHORT; Thanks, that's a good idea, and I did it just like you suggested! > > +} > > > +static void > > +litex_request(struct mmc_host *mmc, struct mmc_request *mrq) > > +{ > > + struct litex_mmc_host *host = mmc_priv(mmc); > > + struct platform_device *pdev = to_platform_device(mmc->parent); > > + struct device *dev = &pdev->dev; > > + struct mmc_data *data = mrq->data; > > + struct mmc_command *sbc = mrq->sbc; > > + struct mmc_command *cmd = mrq->cmd; > > + struct mmc_command *stop = mrq->stop; > > + unsigned int retries = cmd->retries; > > + int status; > > + int sg_count; > > + enum dma_data_direction dir = DMA_TO_DEVICE; > > + bool direct = false; > > + dma_addr_t dma; > > + unsigned int len = 0; > > The above might look nicer when using "reverse Xmas tree" order > of declarations. I did that *partially* -- still wanted to preserve grouping of variables that tend to be related, but I think I fixed the most "egregious" instances of visual mis-alignment :) > > + > > + u32 response_len = litex_response_len(cmd); > > + u32 transfer = SDCARD_CTRL_DATA_TRANSFER_NONE; > > + > > + /* First check that the card is still there */ > > + if (!litex_get_cd(mmc)) { > > + cmd->error = -ENOMEDIUM; > > + mmc_request_done(mmc, mrq); > > + return; > > + } > > + > > + /* Send set-block-count command if needed */ > > + if (sbc) { > > + status = send_cmd(host, sbc->opcode, sbc->arg, > > + litex_response_len(sbc), > > + SDCARD_CTRL_DATA_TRANSFER_NONE); > > + sbc->error = litex_map_status(status); > > + if (status != SD_OK) { > > + host->is_bus_width_set = false; > > + mmc_request_done(mmc, mrq); > > + return; > > + } > > + } > > + > > + if (data) { > > + /* LiteSDCard only supports 4-bit bus width; therefore, we MUST > > + * inject a SET_BUS_WIDTH (acmd6) before the very first data > > + * transfer, earlier than when the mmc subsystem would normally > > + * get around to it! > > + */ > > + if (!host->is_bus_width_set) { > > + ulong n = jiffies + 2 * HZ; // 500ms timeout > > + > > + while (litex_set_bus_width(host) != SD_OK) { > > + if (time_after(jiffies, n)) { > > + dev_warn(dev, "Can't set bus width!\n"); > > + cmd->error = -ETIMEDOUT; > > + mmc_request_done(mmc, mrq); > > + return; > > + } > > + } > > + host->is_bus_width_set = true; > > + } > > + > > + /* Try to DMA directly to/from the data buffer. > > + * We can do that if the buffer can be mapped for DMA > > + * in one contiguous chunk. > > + */ > > + dma = host->dma; > > + len = data->blksz * data->blocks; > > + if (data->flags & MMC_DATA_READ) > > + dir = DMA_FROM_DEVICE; > > + sg_count = dma_map_sg(&host->dev->dev, > > + data->sg, data->sg_len, dir); > > + if (sg_count == 1) { > > + dma = sg_dma_address(data->sg); > > + len = sg_dma_len(data->sg); > > + direct = true; > > + } else if (len > host->buf_size) > > + len = host->buf_size; > > + > > + if (data->flags & MMC_DATA_READ) { > > + litex_write8(host->sdreader + LITEX_BLK2MEM_ENA, 0); > > + litex_write64(host->sdreader + LITEX_BLK2MEM_BASE, dma); > > + litex_write32(host->sdreader + LITEX_BLK2MEM_LEN, len); > > + litex_write8(host->sdreader + LITEX_BLK2MEM_ENA, 1); > > + > > + transfer = SDCARD_CTRL_DATA_TRANSFER_READ; > > + } else if (data->flags & MMC_DATA_WRITE) { > > + if (!direct) > > + sg_copy_to_buffer(data->sg, data->sg_len, > > + host->buffer, len); > > + > > + litex_write8(host->sdwriter + LITEX_MEM2BLK_ENA, 0); > > + litex_write64(host->sdwriter + LITEX_MEM2BLK_BASE, dma); > > + litex_write32(host->sdwriter + LITEX_MEM2BLK_LEN, len); > > + litex_write8(host->sdwriter + LITEX_MEM2BLK_ENA, 1); > > + > > + transfer = SDCARD_CTRL_DATA_TRANSFER_WRITE; > > + } else { > > + dev_warn(dev, "Data present w/o read or write flag.\n"); > > + /* Continue: set cmd status, mark req done */ > > + } > > + > > + litex_write16(host->sdcore + LITEX_CORE_BLKLEN, data->blksz); > > + litex_write32(host->sdcore + LITEX_CORE_BLKCNT, data->blocks); > > + } > > + > > + do { > > + status = send_cmd(host, cmd->opcode, cmd->arg, > > + response_len, transfer); > > + } while (status != SD_OK && retries-- > 0); > > + > > + cmd->error = litex_map_status(status); > > + if (status != SD_OK) > > + /* card may be gone; don't assume bus width is still set */ > > + host->is_bus_width_set = false; > > Please add curly braces. OK. > > + > > + if (response_len == SDCARD_CTRL_RESPONSE_SHORT) { > > + /* pull short response fields from appropriate host registers */ > > + cmd->resp[0] = host->resp[3]; > > + cmd->resp[1] = host->resp[2] & 0xFF; > > + } else if (response_len == SDCARD_CTRL_RESPONSE_LONG) { > > + cmd->resp[0] = host->resp[0]; > > + cmd->resp[1] = host->resp[1]; > > + cmd->resp[2] = host->resp[2]; > > + cmd->resp[3] = host->resp[3]; > > + } > > + > > + /* Send stop-transmission command if required */ > > + if (stop && (cmd->error || !sbc)) { > > + int stop_stat; > > + > > + stop_stat = send_cmd(host, stop->opcode, stop->arg, > > + litex_response_len(stop), > > + SDCARD_CTRL_DATA_TRANSFER_NONE); > > + stop->error = litex_map_status(stop_stat); > > + if (stop_stat != SD_OK) > > + host->is_bus_width_set = false; > > + } > > + > > + if (data) > > + dma_unmap_sg(&host->dev->dev, data->sg, data->sg_len, dir); > > + > > + if (status == SD_OK && transfer != SDCARD_CTRL_DATA_TRANSFER_NONE) { > > + data->bytes_xfered = min(len, mmc->max_req_size); > > + if (transfer == SDCARD_CTRL_DATA_TRANSFER_READ && !direct) { > > + sg_copy_from_buffer(data->sg, sg_nents(data->sg), > > + host->buffer, data->bytes_xfered); > > + } > > + } > > + > > + mmc_request_done(mmc, mrq); > > +} > > + > > +static void > > +litex_set_clk(struct litex_mmc_host *host, unsigned int clk_freq) > > +{ > > + u32 div = clk_freq ? host->freq / clk_freq : 256; > > + > > + div = roundup_pow_of_two(div); > > + div = min_t(u32, max_t(u32, div, 2), 256); > > No need for the _t-variants if you make the constants unsigned (e.g. 2U). Done. > > + dev_info(&host->dev->dev, "sdclk_freq=%d: set to %d via div=%d\n", > > + clk_freq, host->freq / div, div); > > + litex_write16(host->sdphy + LITEX_PHY_CLOCKERDIV, div); > > +} > > > +static int > > +litex_mmc_probe(struct platform_device *pdev) > > +{ > > + struct litex_mmc_host *host; > > + struct mmc_host *mmc; > > + struct device_node *cpu; > > + int ret; > > + > > + 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;` > > + */ > > + if (!mmc) > > + return -ENOMEM; > > + > > + host = mmc_priv(mmc); > > + host->mmc = mmc; > > + host->dev = pdev; > > + > > + host->clock = 0; > > + cpu = of_get_next_cpu_node(NULL); > > + ret = of_property_read_u32(cpu, "clock-frequency", &host->freq); > > + of_node_put(cpu); > > + if (ret) { > > + dev_err(&pdev->dev, "No \"clock-frequency\" property in DT\n"); > > + goto err_free_host; > > + } > > + > > + init_completion(&host->cmd_done); > > + host->irq = platform_get_irq(pdev, 0); > > platform_get_irq_optional() > > So interrupts should not be required in the DT bindings. Got it. > > + if (host->irq < 0) > > + dev_err(&pdev->dev, "Failed to get IRQ, using polling\n"); > > This is not an error condition: dev_info() or dev_warn(). OK. > > + > > + /* LiteSDCard only supports 4-bit bus width; therefore, we MUST inject > > + * a SET_BUS_WIDTH (acmd6) before the very first data transfer, earlier > > + * than when the mmc subsystem would normally get around to it! > > + */ > > + host->is_bus_width_set = false; > > + host->app_cmd = false; > > + > > + ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32)); > > + if (ret) > > + goto err_free_host; > > + > > + host->buf_size = mmc->max_req_size * 2; > > + host->buffer = dma_alloc_coherent(&pdev->dev, host->buf_size, > > + &host->dma, GFP_DMA); > > + if (host->buffer == NULL) { > > + ret = -ENOMEM; > > + goto err_free_host; > > + } > > + > > + host->sdphy = devm_platform_ioremap_resource_byname(pdev, "phy"); > > So reg-names is required ;-) Fixed in the DT bindings document. > > + if (IS_ERR(host->sdphy)) { > > + ret = PTR_ERR(host->sdphy); > > + goto err_free_dma; > > + } > > + > > + host->sdcore = devm_platform_ioremap_resource_byname(pdev, "core"); > > + if (IS_ERR(host->sdcore)) { > > + ret = PTR_ERR(host->sdcore); > > + goto err_free_dma; > > + } > > + > > + host->sdreader = devm_platform_ioremap_resource_byname(pdev, "reader"); > > + if (IS_ERR(host->sdreader)) { > > + ret = PTR_ERR(host->sdreader); > > + goto err_free_dma; > > + } > > + > > + host->sdwriter = devm_platform_ioremap_resource_byname(pdev, "writer"); > > + if (IS_ERR(host->sdwriter)) { > > + ret = PTR_ERR(host->sdwriter); > > + goto err_free_dma; > > + } > > + > > + if (host->irq > 0) { > > + host->sdirq = devm_platform_ioremap_resource_byname(pdev, "irq"); > > So you need a "minItems: 4" for reg{,-names} in the DT bindings. Ditto. > > + if (IS_ERR(host->sdirq)) { > > + ret = PTR_ERR(host->sdirq); > > + goto err_free_dma; > > + } > > + } > > + > > + mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34; > > + mmc->ops = &litex_mmc_ops; > > + > > + mmc->f_min = 12.5e6; > > + mmc->f_max = 50e6; > > + > > + ret = mmc_of_parse(mmc); > > + if (ret) > > + goto err_free_dma; > > + > > + /* force 4-bit bus_width (only width supported by hardware) */ > > + mmc->caps &= ~MMC_CAP_8_BIT_DATA; > > + mmc->caps |= MMC_CAP_4_BIT_DATA; > > + > > + /* set default capabilities */ > > + mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY | > > + MMC_CAP_DRIVER_TYPE_D | > > + MMC_CAP_CMD23; > > + mmc->caps2 |= MMC_CAP2_NO_WRITE_PROTECT | > > + MMC_CAP2_FULL_PWR_CYCLE | > > + MMC_CAP2_NO_SDIO; > > + > > + platform_set_drvdata(pdev, host); > > + > > + ret = mmc_add_host(mmc); > > + if (ret < 0) > > + goto err_free_dma; > > + > > + /* ensure DMA bus masters are disabled */ > > + litex_write8(host->sdreader + LITEX_BLK2MEM_ENA, 0); > > + litex_write8(host->sdwriter + LITEX_MEM2BLK_ENA, 0); > > + > > + /* set up interrupt handler */ > > + if (host->irq > 0) { > > + ret = request_irq(host->irq, litex_mmc_interrupt, 0, > > + "litex-mmc", mmc); > > + if (ret < 0) { > > + dev_err(&pdev->dev, > > + "irq setup error %d, using polling\n", ret); > > + host->irq = 0; > > + } > > + } > > + > > + /* enable card-change interrupts, or else ask for polling */ > > + if (host->irq > 0) { > > + litex_write32(host->sdirq + LITEX_IRQ_PENDING, > > + SDIRQ_CARD_DETECT); /* clears it */ > > + litex_write32(host->sdirq + LITEX_IRQ_ENABLE, > > + SDIRQ_CARD_DETECT); > > + } else { > > + mmc->caps |= MMC_CAP_NEEDS_POLL; > > + } > > + > > + return 0; > > + > > +err_free_dma: > > + dma_free_coherent(&pdev->dev, host->buf_size, host->buffer, host->dma); > > +err_free_host: > > + mmc_free_host(mmc); > > + return ret; > > +} > Thanks again, --Gabriel
