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Message-ID: <CAHp75Vceh32ST68Dwn9mV5XA5j-M8rztFHCPO0kpCdi=RsRvhg@mail.gmail.com>
Date: Sun, 9 Jan 2022 17:06:20 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Gabriel Somlo <gsomlo@...il.com>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Rob Herring <robh+dt@...nel.org>,
devicetree <devicetree@...r.kernel.org>,
Ulf Hansson <ulf.hansson@...aro.org>,
linux-mmc <linux-mmc@...r.kernel.org>,
Karol Gugala <kgugala@...micro.com>,
Mateusz Holenko <mholenko@...micro.com>,
Kamil Rakoczy <krakoczy@...micro.com>,
mdudek@...ernships.antmicro.com,
Paul Mackerras <paulus@...abs.org>,
Joel Stanley <joel@....id.au>,
Stafford Horne <shorne@...il.com>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
david.abdurachmanov@...ive.com,
Florent Kermarrec <florent@...oy-digital.fr>,
Randy Dunlap <rdunlap@...radead.org>, hdanton@...a.com
Subject: Re: [PATCH v10 3/3] mmc: Add driver for LiteX's LiteSDCard interface
On Sun, Jan 9, 2022 at 4:56 PM Gabriel Somlo <gsomlo@...il.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!
LGTM, thanks!
FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
One thing that may be improved later is the interrupt handler. I don't
think it's correct to return IRQ_HANDLED in case there was no CMD or
CD event, but I don't know the hardware either.
> Co-developed-by: Kamil Rakoczy <krakoczy@...micro.com>
> Signed-off-by: Kamil Rakoczy <krakoczy@...micro.com>
> Co-developed-by: Maciej Dudek <mdudek@...ernships.antmicro.com>
> Signed-off-by: Maciej Dudek <mdudek@...ernships.antmicro.com>
> Co-developed-by: Paul Mackerras <paulus@...abs.org>
> Signed-off-by: Paul Mackerras <paulus@...abs.org>
> Signed-off-by: Gabriel Somlo <gsomlo@...il.com>
> Reviewed-by: Joel Stanley <joel@....id.au>
> ---
>
> New in v10:
> drivers/mmc/host/litex_mmc.c:
> - group `linux/mmc/*` includes by themselves
> - clean-up of `return` style (multiple locations throughout source)
> - create `mmc_free_host()` wrapper for use with
> `devm_add_action_or_reset()`
> - use GFP_KERNEL with `dmam_alloc_coherent()`
>
> >New in v9:
> >drivers/mmc/host/Kconfig:
> > - fix OF dependency
> >drivers/mmc/host/litex_mmc.c:
> > - remove `linux/of.h` include, no longer needed since dropping
> > `of_match_ptr()`
> > - add `linux/mod_devicetable.h` include
> > - use devm_action_or_reset() to devm-ify mmc_alloc_host(), and obviate
> > the need to call mmc_free_host() explicitly during either probe()
> > error path or during remove()
> >
> >>New in v8:
> >> - remove `Cc:` lines from commit blurb
> >>drivers/mmc/host/litex_mmc.c:
> >> - fix file header comment (for real, this time)
> >> - add explicit `bits.h` include
> >> - remove `of_match_ptr()` wrapper from around .of_match_table argument
> >> - fix devm ordering issues: use `devm_request_irq()`, which precludes
> >> the need to call `free_irq()` on `probe()` error path or from `remove()`
> >>
> >>>New in v7:
> >>>drivers/mmc/host/Kconfig:
> >>> - added module name in LiteSDCard Kconfig entry
> >>>drivers/mmc/host/litex_mmc.c:
> >>> - fixed comment formatting, ordering, and capitalization throughout
> >>> the entire file
> >>> - sorted header #include statements
> >>> - removed redundant parantheses in readx_poll_timeout() condition
> >>> - explicit handling of readx_poll_timeout() timeout scenarios
> >>> - dev_err() used in litex_mmc_sdcard_wait_done()
> >>> - use memcpy_fromio() to grab command response
> >>> - no need to apply 0xffff mask to a 32-bit value right-shifted by 16
> >>> (host->resp[3])
> >>> - use clamp() instead of min(max(...)...)
> >>> - reworked platform_get_irq_optional() error handling logic
> >>> - no need to explicitly zero host->irq, kzalloc() does that already
> >>> - added missing free_irq() in litex_mmc_probe() error path
> >>> - reordered calls inside litex_mmc_remove() (calling mmc_free_host()
> >>> before free_irq()
> >>>
> >>>>New in v6:
> >>>> - fix handling of deferred probe vs. platform_get_irq_optional()
> >>>> - don't #ifdef dma_set_mask_and_coherent(), since it automatically
> >>>> does the right thing on both 32- and 64-bit DMA capable arches
> >>>> - remove MMC_CAP2_FULL_PWR_CYCLE, add MMC_CAP2_NO_MMC to list of
> >>>> hardcoded capabilities during litex_mmc_probe()
> >>>> - hardcode mmc->ocr_avail to the full 2.7-3.6V range allowed by the
> >>>> SDCard spec (the LiteSDCard device doesn't accept software
> >>>> configuration)
> >>>>
> >>>>>New in v5:
> >>>>> - shorter #define constant names (cosmetic, make them less unwieldy)
> >>>>> - picked up reviewed-by Joel
> >>>>>
> >>>>>>New in v4:
> >>>>>> - struct litex_mmc_host fields re-ordered so that `pahole` reports
> >>>>>> no holes on either 32- or 64-bit builds
> >>>>>> - litex_mmc_set_bus_width() now encapsulates check for
> >>>>>> host->is_bus_width_set
> >>>>>> - litex_mmc_request() - factor out dma data setup into separate
> >>>>>> helper function: litex_mmc_do_dma()
> >>>>>>
> >>>>>>> New in v3:
> >>>>>>> - fixed function signature (no line split), and naming (litex_mmc_*)
> >>>>>>> - more informative MODULE_AUTHOR() entries
> >>>>>>> - also added matching "Copyright" entries in file header
> >>>>>>> - fixed description and dependencies in Kconfig
> >>>>>>> - removed magic constants
> >>>>>>> - removed litex_map_status(), have sdcard_wait_done() return *real*
> >>>>>>> error codes directly instead.
> >>>>>>> - streamlined litex_mmc_reponse_len()
> >>>>>>> - call litex_mmc_set_bus_width() only once, and ensure it returns
> >>>>>>> correct error code(s)
> >>>>>>> - use readx_poll_timeout() -- more concise -- instead of
> >>>>>>> read_poll_timeout()
> >>>>>>> - use dev_err() in litex_mmc_send_cmd() (instead of pr_err())
> >>>>>>> - litex_mmc_setclk() will update host->clock before returning
> >>>>>>> - separate irq initialization into its own function,
> >>>>>>> litex_mmc_irq_init()
> >>>>>>> - document rationale for f_min, f_max
> >>>>>>> - use dmam_alloc_coherent(), which simplifies cleanup significantly
> >>>>>>> - bump dma_set_mask_and_coherent() to 64-bits on suitable
> >>>>>>> architectures
> >>>>>>> - clock source picked up from dedicated DT clock reference property
> >>>>>>> - remove gpio card-detect logic (needs testing and a dt binding
> >>>>>>> example before being eligible for upstream inclusion)
> >>>>>>> - large `if (data) { ... }` block in litex_mmc_request() left as-is,
> >>>>>>> there are too many variables shared with the rest of the parent
> >>>>>>> function body to easily separate (e.g., `len`, `transfer`, `direct`).
> >>>>>>> If this is indeed a blocker, I can take another shot at refactoring
> >>>>>>> it in a future revision!
>
> drivers/mmc/host/Kconfig | 9 +
> drivers/mmc/host/Makefile | 1 +
> drivers/mmc/host/litex_mmc.c | 655 +++++++++++++++++++++++++++++++++++
> 3 files changed, 665 insertions(+)
> create mode 100644 drivers/mmc/host/litex_mmc.c
>
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 5af8494c31b5..8f661f52b502 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -1093,3 +1093,12 @@ config MMC_OWL
>
> config MMC_SDHCI_EXTERNAL_DMA
> bool
> +
> +config MMC_LITEX
> + tristate "LiteX MMC Host Controller support"
> + depends on ((PPC_MICROWATT || LITEX) && OF) || COMPILE_TEST
> + help
> + This selects support for the MMC Host Controller found in LiteX SoCs.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called litex_mmc.
> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> index ea36d379bd3c..4e4ceb32c4b4 100644
> --- a/drivers/mmc/host/Makefile
> +++ b/drivers/mmc/host/Makefile
> @@ -101,6 +101,7 @@ obj-$(CONFIG_MMC_CQHCI) += cqhci.o
> cqhci-y += cqhci-core.o
> cqhci-$(CONFIG_MMC_CRYPTO) += cqhci-crypto.o
> obj-$(CONFIG_MMC_HSQ) += mmc_hsq.o
> +obj-$(CONFIG_MMC_LITEX) += litex_mmc.o
>
> ifeq ($(CONFIG_CB710_DEBUG),y)
> CFLAGS-cb710-mmc += -DDEBUG
> diff --git a/drivers/mmc/host/litex_mmc.c b/drivers/mmc/host/litex_mmc.c
> new file mode 100644
> index 000000000000..db1858e343c7
> --- /dev/null
> +++ b/drivers/mmc/host/litex_mmc.c
> @@ -0,0 +1,655 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * LiteX LiteSDCard driver
> + *
> + * Copyright (C) 2019-2020 Antmicro <contact@...micro.com>
> + * Copyright (C) 2019-2020 Kamil Rakoczy <krakoczy@...micro.com>
> + * Copyright (C) 2019-2020 Maciej Dudek <mdudek@...ernships.antmicro.com>
> + * Copyright (C) 2020 Paul Mackerras <paulus@...abs.org>
> + * Copyright (C) 2020-2021 Gabriel Somlo <gsomlo@...il.com>
> + */
> +
> +#include <linux/bits.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/interrupt.h>
> +#include <linux/iopoll.h>
> +#include <linux/litex.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +#include <linux/mmc/host.h>
> +#include <linux/mmc/mmc.h>
> +#include <linux/mmc/sd.h>
> +
> +#define LITEX_PHY_CARDDETECT 0x00
> +#define LITEX_PHY_CLOCKERDIV 0x04
> +#define LITEX_PHY_INITIALIZE 0x08
> +#define LITEX_PHY_WRITESTATUS 0x0C
> +#define LITEX_CORE_CMDARG 0x00
> +#define LITEX_CORE_CMDCMD 0x04
> +#define LITEX_CORE_CMDSND 0x08
> +#define LITEX_CORE_CMDRSP 0x0C
> +#define LITEX_CORE_CMDEVT 0x1C
> +#define LITEX_CORE_DATEVT 0x20
> +#define LITEX_CORE_BLKLEN 0x24
> +#define LITEX_CORE_BLKCNT 0x28
> +#define LITEX_BLK2MEM_BASE 0x00
> +#define LITEX_BLK2MEM_LEN 0x08
> +#define LITEX_BLK2MEM_ENA 0x0C
> +#define LITEX_BLK2MEM_DONE 0x10
> +#define LITEX_BLK2MEM_LOOP 0x14
> +#define LITEX_MEM2BLK_BASE 0x00
> +#define LITEX_MEM2BLK_LEN 0x08
> +#define LITEX_MEM2BLK_ENA 0x0C
> +#define LITEX_MEM2BLK_DONE 0x10
> +#define LITEX_MEM2BLK_LOOP 0x14
> +#define LITEX_MEM2BLK 0x18
> +#define LITEX_IRQ_STATUS 0x00
> +#define LITEX_IRQ_PENDING 0x04
> +#define LITEX_IRQ_ENABLE 0x08
> +
> +#define SD_CTL_DATA_XFER_NONE 0
> +#define SD_CTL_DATA_XFER_READ 1
> +#define SD_CTL_DATA_XFER_WRITE 2
> +
> +#define SD_CTL_RESP_NONE 0
> +#define SD_CTL_RESP_SHORT 1
> +#define SD_CTL_RESP_LONG 2
> +#define SD_CTL_RESP_SHORT_BUSY 3
> +
> +#define SD_BIT_DONE BIT(0)
> +#define SD_BIT_WR_ERR BIT(1)
> +#define SD_BIT_TIMEOUT BIT(2)
> +#define SD_BIT_CRC_ERR BIT(3)
> +
> +#define SD_SLEEP_US 5
> +#define SD_TIMEOUT_US 20000
> +
> +#define SDIRQ_CARD_DETECT 1
> +#define SDIRQ_SD_TO_MEM_DONE 2
> +#define SDIRQ_MEM_TO_SD_DONE 4
> +#define SDIRQ_CMD_DONE 8
> +
> +#define LITEX_MMC_OCR (MMC_VDD_27_28 | MMC_VDD_28_29 | MMC_VDD_29_30 | \
> + MMC_VDD_30_31 | MMC_VDD_31_32 | MMC_VDD_32_33 | \
> + MMC_VDD_33_34 | MMC_VDD_34_35 | MMC_VDD_35_36)
> +
> +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;
> +
> + void *buffer;
> + size_t buf_size;
> + dma_addr_t dma;
> +
> + struct completion cmd_done;
> + int irq;
> +
> + unsigned int ref_clk;
> + unsigned int sd_clk;
> +
> + u32 resp[4];
> + u16 rca;
> +
> + bool is_bus_width_set;
> + bool app_cmd;
> +};
> +
> +static int litex_mmc_sdcard_wait_done(void __iomem *reg, struct device *dev)
> +{
> + u8 evt;
> + int ret;
> +
> + ret = readx_poll_timeout(litex_read8, reg, evt, evt & SD_BIT_DONE,
> + SD_SLEEP_US, SD_TIMEOUT_US);
> + if (ret)
> + return ret;
> + if (evt == SD_BIT_DONE)
> + return 0;
> + if (evt & SD_BIT_WR_ERR)
> + return -EIO;
> + if (evt & SD_BIT_TIMEOUT)
> + return -ETIMEDOUT;
> + if (evt & SD_BIT_CRC_ERR)
> + return -EILSEQ;
> + dev_err(dev, "%s: unknown error (evt=%x)\n", __func__, evt);
> + return -EINVAL;
> +}
> +
> +static int litex_mmc_send_cmd(struct litex_mmc_host *host,
> + u8 cmd, u32 arg, u8 response_len, u8 transfer)
> +{
> + struct device *dev = mmc_dev(host->mmc);
> + void __iomem *reg;
> + int ret;
> + u8 evt;
> +
> + 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 != SD_CTL_DATA_XFER_NONE ||
> + response_len == SD_CTL_RESP_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);
> + }
> +
> + ret = litex_mmc_sdcard_wait_done(host->sdcore + LITEX_CORE_CMDEVT, dev);
> + if (ret) {
> + dev_err(dev, "Command (cmd %d) error, status %d\n", cmd, ret);
> + return ret;
> + }
> +
> + if (response_len != SD_CTL_RESP_NONE) {
> + /*
> + * NOTE: this matches the semantics of litex_read32()
> + * regardless of underlying arch endianness!
> + */
> + memcpy_fromio(host->resp,
> + host->sdcore + LITEX_CORE_CMDRSP, 0x10);
> + }
> +
> + if (!host->app_cmd && cmd == SD_SEND_RELATIVE_ADDR)
> + host->rca = (host->resp[3] >> 16);
> +
> + host->app_cmd = (cmd == MMC_APP_CMD);
> +
> + if (transfer == SD_CTL_DATA_XFER_NONE)
> + return ret; /* OK from prior litex_mmc_sdcard_wait_done() */
> +
> + ret = litex_mmc_sdcard_wait_done(host->sdcore + LITEX_CORE_DATEVT, dev);
> + if (ret) {
> + dev_err(dev, "Data xfer (cmd %d) error, status %d\n", cmd, ret);
> + return ret;
> + }
> +
> + /* Wait for completion of (read or write) DMA transfer */
> + reg = (transfer == SD_CTL_DATA_XFER_READ) ?
> + host->sdreader + LITEX_BLK2MEM_DONE :
> + host->sdwriter + LITEX_MEM2BLK_DONE;
> + ret = readx_poll_timeout(litex_read8, reg, evt, evt & SD_BIT_DONE,
> + SD_SLEEP_US, SD_TIMEOUT_US);
> + if (ret)
> + dev_err(dev, "DMA timeout (cmd %d)\n", cmd);
> +
> + return ret;
> +}
> +
> +static int litex_mmc_send_app_cmd(struct litex_mmc_host *host)
> +{
> + return litex_mmc_send_cmd(host, MMC_APP_CMD, host->rca << 16,
> + SD_CTL_RESP_SHORT, SD_CTL_DATA_XFER_NONE);
> +}
> +
> +static int litex_mmc_send_set_bus_w_cmd(struct litex_mmc_host *host, u32 width)
> +{
> + return litex_mmc_send_cmd(host, SD_APP_SET_BUS_WIDTH, width,
> + SD_CTL_RESP_SHORT, SD_CTL_DATA_XFER_NONE);
> +}
> +
> +static int litex_mmc_set_bus_width(struct litex_mmc_host *host)
> +{
> + bool app_cmd_sent;
> + int ret;
> +
> + if (host->is_bus_width_set)
> + return 0;
> +
> + /* Ensure 'app_cmd' precedes 'app_set_bus_width_cmd' */
> + app_cmd_sent = host->app_cmd; /* was preceding command app_cmd? */
> + if (!app_cmd_sent) {
> + ret = litex_mmc_send_app_cmd(host);
> + if (ret)
> + return ret;
> + }
> +
> + /* LiteSDCard only supports 4-bit bus width */
> + ret = litex_mmc_send_set_bus_w_cmd(host, MMC_BUS_WIDTH_4);
> + if (ret)
> + return ret;
> +
> + /* Re-send 'app_cmd' if necessary */
> + if (app_cmd_sent) {
> + ret = litex_mmc_send_app_cmd(host);
> + if (ret)
> + return ret;
> + }
> +
> + host->is_bus_width_set = true;
> +
> + return 0;
> +}
> +
> +static int litex_mmc_get_cd(struct mmc_host *mmc)
> +{
> + struct litex_mmc_host *host = mmc_priv(mmc);
> + int ret;
> +
> + if (!mmc_card_is_removable(mmc))
> + return 1;
> +
> + ret = !litex_read8(host->sdphy + LITEX_PHY_CARDDETECT);
> + if (ret)
> + return ret;
> +
> + /* Ensure bus width will be set (again) upon card (re)insertion */
> + host->is_bus_width_set = false;
> +
> + return 0;
> +}
> +
> +static irqreturn_t litex_mmc_interrupt(int irq, void *arg)
> +{
> + struct mmc_host *mmc = arg;
> + struct litex_mmc_host *host = mmc_priv(mmc);
> + u32 pending = litex_read32(host->sdirq + LITEX_IRQ_PENDING);
> +
> + /* Check for card change interrupt */
> + if (pending & SDIRQ_CARD_DETECT) {
> + litex_write32(host->sdirq + LITEX_IRQ_PENDING,
> + SDIRQ_CARD_DETECT);
> + mmc_detect_change(mmc, msecs_to_jiffies(10));
> + }
> +
> + /* Check for command completed */
> + if (pending & SDIRQ_CMD_DONE) {
> + /* Disable it so it doesn't keep interrupting */
> + litex_write32(host->sdirq + LITEX_IRQ_ENABLE,
> + SDIRQ_CARD_DETECT);
> + complete(&host->cmd_done);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static u32 litex_mmc_response_len(struct mmc_command *cmd)
> +{
> + if (cmd->flags & MMC_RSP_136)
> + return SD_CTL_RESP_LONG;
> + if (!(cmd->flags & MMC_RSP_PRESENT))
> + return SD_CTL_RESP_NONE;
> + if (cmd->flags & MMC_RSP_BUSY)
> + return SD_CTL_RESP_SHORT_BUSY;
> + return SD_CTL_RESP_SHORT;
> +}
> +
> +static void litex_mmc_do_dma(struct litex_mmc_host *host, struct mmc_data *data,
> + unsigned int *len, bool *direct, u8 *transfer)
> +{
> + struct device *dev = mmc_dev(host->mmc);
> + dma_addr_t dma;
> + int sg_count;
> +
> + /*
> + * 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;
> + sg_count = dma_map_sg(dev, data->sg, data->sg_len,
> + mmc_get_dma_dir(data));
> + 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 = SD_CTL_DATA_XFER_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 = SD_CTL_DATA_XFER_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);
> +}
> +
> +static void litex_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
> +{
> + struct litex_mmc_host *host = mmc_priv(mmc);
> + struct device *dev = mmc_dev(mmc);
> + struct mmc_command *cmd = mrq->cmd;
> + struct mmc_command *sbc = mrq->sbc;
> + struct mmc_data *data = mrq->data;
> + struct mmc_command *stop = mrq->stop;
> + unsigned int retries = cmd->retries;
> + unsigned int len = 0;
> + bool direct = false;
> + u32 response_len = litex_mmc_response_len(cmd);
> + u8 transfer = SD_CTL_DATA_XFER_NONE;
> +
> + /* First check that the card is still there */
> + if (!litex_mmc_get_cd(mmc)) {
> + cmd->error = -ENOMEDIUM;
> + mmc_request_done(mmc, mrq);
> + return;
> + }
> +
> + /* Send set-block-count command if needed */
> + if (sbc) {
> + sbc->error = litex_mmc_send_cmd(host, sbc->opcode, sbc->arg,
> + litex_mmc_response_len(sbc),
> + SD_CTL_DATA_XFER_NONE);
> + if (sbc->error) {
> + 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!
> + */
> + cmd->error = litex_mmc_set_bus_width(host);
> + if (cmd->error) {
> + dev_err(dev, "Can't set bus width!\n");
> + mmc_request_done(mmc, mrq);
> + return;
> + }
> +
> + litex_mmc_do_dma(host, data, &len, &direct, &transfer);
> + }
> +
> + do {
> + cmd->error = litex_mmc_send_cmd(host, cmd->opcode, cmd->arg,
> + response_len, transfer);
> + } while (cmd->error && retries-- > 0);
> +
> + if (cmd->error) {
> + /* Card may be gone; don't assume bus width is still set */
> + host->is_bus_width_set = false;
> + }
> +
> + if (response_len == SD_CTL_RESP_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 == SD_CTL_RESP_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)) {
> + stop->error = litex_mmc_send_cmd(host, stop->opcode, stop->arg,
> + litex_mmc_response_len(stop),
> + SD_CTL_DATA_XFER_NONE);
> + if (stop->error)
> + host->is_bus_width_set = false;
> + }
> +
> + if (data) {
> + dma_unmap_sg(dev, data->sg, data->sg_len,
> + mmc_get_dma_dir(data));
> + }
> +
> + if (!cmd->error && transfer != SD_CTL_DATA_XFER_NONE) {
> + data->bytes_xfered = min(len, mmc->max_req_size);
> + if (transfer == SD_CTL_DATA_XFER_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_mmc_setclk(struct litex_mmc_host *host, unsigned int freq)
> +{
> + struct device *dev = mmc_dev(host->mmc);
> + u32 div;
> +
> + div = freq ? host->ref_clk / freq : 256U;
> + div = roundup_pow_of_two(div);
> + div = clamp(div, 2U, 256U);
> + dev_dbg(dev, "sd_clk_freq=%d: set to %d via div=%d\n",
> + freq, host->ref_clk / div, div);
> + litex_write16(host->sdphy + LITEX_PHY_CLOCKERDIV, div);
> + host->sd_clk = freq;
> +}
> +
> +static void litex_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> +{
> + struct litex_mmc_host *host = mmc_priv(mmc);
> +
> + /*
> + * NOTE: Ignore any ios->bus_width updates; they occur right after
> + * the mmc core sends its own acmd6 bus-width change notification,
> + * which is redundant since we snoop on the command flow and inject
> + * an early acmd6 before the first data transfer command is sent!
> + */
> +
> + /* Update sd_clk */
> + if (ios->clock != host->sd_clk)
> + litex_mmc_setclk(host, ios->clock);
> +}
> +
> +static const struct mmc_host_ops litex_mmc_ops = {
> + .get_cd = litex_mmc_get_cd,
> + .request = litex_mmc_request,
> + .set_ios = litex_mmc_set_ios,
> +};
> +
> +static int litex_mmc_irq_init(struct litex_mmc_host *host)
> +{
> + struct device *dev = mmc_dev(host->mmc);
> + int ret;
> +
> + 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;
> + }
> +
> + host->sdirq = devm_platform_ioremap_resource_byname(host->dev, "irq");
> + if (IS_ERR(host->sdirq))
> + return PTR_ERR(host->sdirq);
> +
> + ret = devm_request_irq(dev, host->irq, litex_mmc_interrupt, 0,
> + "litex-mmc", host->mmc);
> + if (ret < 0) {
> + dev_warn(dev, "IRQ request error %d, using polling\n", ret);
> + goto use_polling;
> + }
> +
> + /* Clear & enable card-change interrupts */
> + litex_write32(host->sdirq + LITEX_IRQ_PENDING, SDIRQ_CARD_DETECT);
> + litex_write32(host->sdirq + LITEX_IRQ_ENABLE, SDIRQ_CARD_DETECT);
> +
> + return 0;
> +
> +use_polling:
> + host->mmc->caps |= MMC_CAP_NEEDS_POLL;
> + return 0;
> +}
> +
> +static void litex_mmc_free_host_wrapper(void *mmc)
> +{
> + mmc_free_host(mmc);
> +}
> +
> +static int litex_mmc_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct litex_mmc_host *host;
> + struct mmc_host *mmc;
> + struct clk *clk;
> + int ret;
> +
> + /*
> + * 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;`
> + */
> + mmc = mmc_alloc_host(sizeof(struct litex_mmc_host), dev);
> + if (!mmc)
> + return -ENOMEM;
> +
> + ret = devm_add_action_or_reset(dev, litex_mmc_free_host_wrapper, mmc);
> + if (ret)
> + return dev_err_probe(dev, ret,
> + "Can't register mmc_free_host action\n");
> +
> + host = mmc_priv(mmc);
> + host->mmc = mmc;
> + host->dev = pdev;
> +
> + /* Initialize clock source */
> + clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(clk))
> + return dev_err_probe(dev, PTR_ERR(clk), "can't get clock\n");
> + host->ref_clk = clk_get_rate(clk);
> + host->sd_clk = 0;
> +
> + /*
> + * 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;
> +
> + /* LiteSDCard can support 64-bit DMA addressing */
> + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
> + if (ret)
> + return ret;
> +
> + host->buf_size = mmc->max_req_size * 2;
> + host->buffer = dmam_alloc_coherent(dev, host->buf_size,
> + &host->dma, GFP_KERNEL);
> + if (host->buffer == NULL)
> + return -ENOMEM;
> +
> + host->sdphy = devm_platform_ioremap_resource_byname(pdev, "phy");
> + if (IS_ERR(host->sdphy))
> + return PTR_ERR(host->sdphy);
> +
> + host->sdcore = devm_platform_ioremap_resource_byname(pdev, "core");
> + if (IS_ERR(host->sdcore))
> + return PTR_ERR(host->sdcore);
> +
> + host->sdreader = devm_platform_ioremap_resource_byname(pdev, "reader");
> + if (IS_ERR(host->sdreader))
> + return PTR_ERR(host->sdreader);
> +
> + host->sdwriter = devm_platform_ioremap_resource_byname(pdev, "writer");
> + if (IS_ERR(host->sdwriter))
> + return PTR_ERR(host->sdwriter);
> +
> + /* Ensure DMA bus masters are disabled */
> + litex_write8(host->sdreader + LITEX_BLK2MEM_ENA, 0);
> + litex_write8(host->sdwriter + LITEX_MEM2BLK_ENA, 0);
> +
> + init_completion(&host->cmd_done);
> + ret = litex_mmc_irq_init(host);
> + if (ret)
> + return ret;
> +
> + /* Allow full generic 2.7-3.6V range; no software tuning available */
> + mmc->ocr_avail = LITEX_MMC_OCR;
> +
> + mmc->ops = &litex_mmc_ops;
> +
> + /*
> + * Set default sd_clk frequency range based on empirical observations
> + * of LiteSDCard gateware behavior on typical SDCard media
> + */
> + mmc->f_min = 12.5e6;
> + mmc->f_max = 50e6;
> +
> + ret = mmc_of_parse(mmc);
> + if (ret)
> + return ret;
> +
> + /* 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_NO_SDIO |
> + MMC_CAP2_NO_MMC;
> +
> + platform_set_drvdata(pdev, host);
> +
> + return mmc_add_host(mmc);
> +}
> +
> +static int litex_mmc_remove(struct platform_device *pdev)
> +{
> + struct litex_mmc_host *host = platform_get_drvdata(pdev);
> +
> + mmc_remove_host(host->mmc);
> + return 0;
> +}
> +
> +static const struct of_device_id litex_match[] = {
> + { .compatible = "litex,mmc" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, litex_match);
> +
> +static struct platform_driver litex_mmc_driver = {
> + .probe = litex_mmc_probe,
> + .remove = litex_mmc_remove,
> + .driver = {
> + .name = "litex-mmc",
> + .of_match_table = litex_match,
> + },
> +};
> +module_platform_driver(litex_mmc_driver);
> +
> +MODULE_DESCRIPTION("LiteX SDCard driver");
> +MODULE_AUTHOR("Antmicro <contact@...micro.com>");
> +MODULE_AUTHOR("Kamil Rakoczy <krakoczy@...micro.com>");
> +MODULE_AUTHOR("Maciej Dudek <mdudek@...ernships.antmicro.com>");
> +MODULE_AUTHOR("Paul Mackerras <paulus@...abs.org>");
> +MODULE_AUTHOR("Gabriel Somlo <gsomlo@...il.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.31.1
>
--
With Best Regards,
Andy Shevchenko
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