* Re: [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface
2022-01-07 17:06 ` [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface Gabriel Somlo
@ 2022-01-07 17:08 ` Gabriel L. Somlo
2022-01-07 20:50 ` Andy Shevchenko
2022-01-07 17:10 ` Gabriel L. Somlo
2022-01-07 20:54 ` Andy Shevchenko
2 siblings, 1 reply; 13+ messages in thread
From: Gabriel L. Somlo @ 2022-01-07 17:08 UTC (permalink / raw)
To: andy.shevchenko
Cc: robh+dt, devicetree, ulf.hansson, linux-mmc, kgugala, mholenko,
krakoczy, mdudek, paulus, joel, shorne, geert,
david.abdurachmanov, florent, rdunlap, linux-kernel
Hi Andy,
A couple of remaining questions regarding your review inline, below:
On Fri, Jan 07, 2022 at 12:06:16PM -0500, Gabriel Somlo 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@antmicro.com>
> Signed-off-by: Kamil Rakoczy <krakoczy@antmicro.com>
> Co-developed-by: Maciej Dudek <mdudek@internships.antmicro.com>
> Signed-off-by: Maciej Dudek <mdudek@internships.antmicro.com>
> Co-developed-by: Paul Mackerras <paulus@ozlabs.org>
> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
> Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
> Cc: Mateusz Holenko <mholenko@antmicro.com>
> Cc: Karol Gugala <kgugala@antmicro.com>
> Cc: Joel Stanley <joel@jms.id.au>
> Cc: Stafford Horne <shorne@gmail.com>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: David Abdurachmanov <david.abdurachmanov@sifive.com>
> Cc: Florent Kermarrec <florent@enjoy-digital.fr>
> Reviewed-by: Joel Stanley <joel@jms.id.au>
> ---
>
> 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 | 10 +
> drivers/mmc/host/Makefile | 1 +
> drivers/mmc/host/litex_mmc.c | 670 +++++++++++++++++++++++++++++++++++
> 3 files changed, 681 insertions(+)
> create mode 100644 drivers/mmc/host/litex_mmc.c
>
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 5af8494c31b5..a24561b74f18 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -1093,3 +1093,13 @@ config MMC_OWL
>
> config MMC_SDHCI_EXTERNAL_DMA
> bool
> +
> +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.
> +
> + 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..3719115850d9
> --- /dev/null
> +++ b/drivers/mmc/host/litex_mmc.c
> @@ -0,0 +1,670 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * 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>
> + *
> + */
It looked to me like you thought I should `#include <linux/bits.h>` here
(even though I'm not getting any compiler warnings regarding it). If so,
why? If not, apologies for the misunderstanding :)
> +#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/module.h>
> +#include <linux/mmc/host.h>
> +#include <linux/mmc/mmc.h>
> +#include <linux/mmc/sd.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.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);
> +
> + /* Ensure bus width will be set (again) upon card (re)insertion */
> + if (ret == 0)
> + host->is_bus_width_set = false;
> +
> + return ret;
> +}
> +
> +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 = request_irq(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 int litex_mmc_probe(struct platform_device *pdev)
> +{
> + 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), &pdev->dev);
> + if (!mmc)
> + return -ENOMEM;
> +
> + host = mmc_priv(mmc);
> + host->mmc = mmc;
> + host->dev = pdev;
> +
> + /* Initialize clock source */
> + clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(clk)) {
> + ret = dev_err_probe(&pdev->dev,
> + PTR_ERR(clk), "can't get clock\n");
> + goto err;
> + }
> + 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(&pdev->dev, DMA_BIT_MASK(64));
> + if (ret)
> + goto err;
> +
> + host->buf_size = mmc->max_req_size * 2;
> + host->buffer = dmam_alloc_coherent(&pdev->dev, host->buf_size,
> + &host->dma, GFP_DMA);
> + if (host->buffer == NULL) {
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + host->sdphy = devm_platform_ioremap_resource_byname(pdev, "phy");
> + if (IS_ERR(host->sdphy)) {
> + ret = PTR_ERR(host->sdphy);
> + goto err;
> + }
> +
> + host->sdcore = devm_platform_ioremap_resource_byname(pdev, "core");
> + if (IS_ERR(host->sdcore)) {
> + ret = PTR_ERR(host->sdcore);
> + goto err;
> + }
> +
> + host->sdreader = devm_platform_ioremap_resource_byname(pdev, "reader");
> + if (IS_ERR(host->sdreader)) {
> + ret = PTR_ERR(host->sdreader);
> + goto err;
> + }
> +
> + host->sdwriter = devm_platform_ioremap_resource_byname(pdev, "writer");
> + if (IS_ERR(host->sdwriter)) {
> + ret = PTR_ERR(host->sdwriter);
> + goto err;
> + }
> +
> + /* 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)
> + goto err;
> +
> + /* 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)
> + goto err;
> +
> + /* 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);
> +
> + ret = mmc_add_host(mmc);
> + if (ret < 0)
> + goto err;
> +
> + return 0;
> +
> +err:
> + if (host->irq > 0)
> + free_irq(host->irq, mmc);
> + mmc_free_host(mmc);
> + return ret;
> +}
Any more ordering or devm vs. non-devm mixing violations here? If so,
can you please link me to an example or some docs where I ould figure
out what it is I'm still doing wrong?
> +static int litex_mmc_remove(struct platform_device *pdev)
> +{
> + struct litex_mmc_host *host = dev_get_drvdata(&pdev->dev);
> + struct mmc_host *mmc = host->mmc;
> +
> + mmc_remove_host(mmc);
> + if (host->irq > 0)
> + free_irq(host->irq, mmc);
> + mmc_free_host(mmc);
> +
> + return 0;
> +}
Ditto here...
> +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 = of_match_ptr(litex_match),
You said "Wrong usage of of_match_ptr()" here, and all I have to go by
is a bunch of other `drivers/mmc/host/*.c` files that use it in a
similar way, so can you please clarify and/or provide an example of how
to do it properly?
Thanks much,
--Gabriel
> + },
> +};
> +module_platform_driver(litex_mmc_driver);
> +
> +MODULE_DESCRIPTION("LiteX SDCard driver");
> +MODULE_AUTHOR("Antmicro <contact@antmicro.com>");
> +MODULE_AUTHOR("Kamil Rakoczy <krakoczy@antmicro.com>");
> +MODULE_AUTHOR("Maciej Dudek <mdudek@internships.antmicro.com>");
> +MODULE_AUTHOR("Paul Mackerras <paulus@ozlabs.org>");
> +MODULE_AUTHOR("Gabriel Somlo <gsomlo@gmail.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.31.1
>
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface
2022-01-07 17:08 ` Gabriel L. Somlo
@ 2022-01-07 20:50 ` Andy Shevchenko
2022-01-07 20:58 ` Andy Shevchenko
2022-01-07 21:23 ` Gabriel L. Somlo
0 siblings, 2 replies; 13+ messages in thread
From: Andy Shevchenko @ 2022-01-07 20:50 UTC (permalink / raw)
To: Gabriel L. Somlo
Cc: Rob Herring, devicetree, Ulf Hansson, linux-mmc, Karol Gugala,
Mateusz Holenko, Kamil Rakoczy, mdudek, Paul Mackerras,
Joel Stanley, Stafford Horne, Geert Uytterhoeven,
david.abdurachmanov, Florent Kermarrec, Randy Dunlap,
Linux Kernel Mailing List
On Fri, Jan 7, 2022 at 7:08 PM Gabriel L. Somlo <gsomlo@gmail.com> wrote:
> On Fri, Jan 07, 2022 at 12:06:16PM -0500, Gabriel Somlo wrote:
...
> > Cc: Mateusz Holenko <mholenko@antmicro.com>
> > Cc: Karol Gugala <kgugala@antmicro.com>
> > Cc: Joel Stanley <joel@jms.id.au>
> > Cc: Stafford Horne <shorne@gmail.com>
> > Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> > Cc: David Abdurachmanov <david.abdurachmanov@sifive.com>
> > Cc: Florent Kermarrec <florent@enjoy-digital.fr>
It would be nice if you can use `git send-email --cc ...` instead of
putting a long list into a commit message.
...
> It looked to me like you thought I should `#include <linux/bits.h>` here
> (even though I'm not getting any compiler warnings regarding it). If so,
> why? If not, apologies for the misunderstanding :)
The rule of thumb is to explicitly use the headers you are the direct
user of with the remark that some of them are guaranteed to be
included by others and some of them should be used (in most cases)
instead of their low-level parts (the example is types.h vs
compiler_attributes.h, so former is more standard than the letter and
it's almost 100% guarantee you want to have something from types.h
anyway in your code).
So, BIT() is defined in bits.h and in the below list none of the
header _guarantees_ its indirect inclusion.
> > +#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/module.h>
> > +#include <linux/mmc/host.h>
> > +#include <linux/mmc/mmc.h>
> > +#include <linux/mmc/sd.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
...
> Any more ordering or devm vs. non-devm mixing violations here? If so,
> can you please link me to an example or some docs where I ould figure
> out what it is I'm still doing wrong?
Device managed resources are attached to the instance of the device
object and removed in the order they have been attached to, but with
the caveat that they have no clue about non-managed calls in between.
Now you may figure out what happens. Ex.:
probe()
A
devm_B
C
devm_D
remove()
un_C
un_A
WRONG!
> > +static int litex_mmc_remove(struct platform_device *pdev)
> > +{
> > + struct litex_mmc_host *host = dev_get_drvdata(&pdev->dev);
> > + struct mmc_host *mmc = host->mmc;
> > +
> > + mmc_remove_host(mmc);
> > + if (host->irq > 0)
> > + free_irq(host->irq, mmc);
> > + mmc_free_host(mmc);
> > +
> > + return 0;
> > +}
>
> Ditto here...
Ditto.
...
> > + .of_match_table = of_match_ptr(litex_match),
>
> You said "Wrong usage of of_match_ptr()" here, and all I have to go by
> is a bunch of other `drivers/mmc/host/*.c` files that use it in a
> similar way, so can you please clarify and/or provide an example of how
> to do it properly?
First of all, you have a dependency to OF, try to remove it and
compile with OF=n and you will immediately see the issue. You may also
go for `git log --no-merges --grep of_match_ptr` and analyze the
result.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface
2022-01-07 20:50 ` Andy Shevchenko
@ 2022-01-07 20:58 ` Andy Shevchenko
2022-01-07 23:15 ` Gabriel L. Somlo
2022-01-07 21:23 ` Gabriel L. Somlo
1 sibling, 1 reply; 13+ messages in thread
From: Andy Shevchenko @ 2022-01-07 20:58 UTC (permalink / raw)
To: Gabriel L. Somlo
Cc: Rob Herring, devicetree, Ulf Hansson, linux-mmc, Karol Gugala,
Mateusz Holenko, Kamil Rakoczy, mdudek, Paul Mackerras,
Joel Stanley, Stafford Horne, Geert Uytterhoeven,
david.abdurachmanov, Florent Kermarrec, Randy Dunlap,
Linux Kernel Mailing List
On Fri, Jan 7, 2022 at 10:50 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Fri, Jan 7, 2022 at 7:08 PM Gabriel L. Somlo <gsomlo@gmail.com> wrote:
> > On Fri, Jan 07, 2022 at 12:06:16PM -0500, Gabriel Somlo wrote:
...
> > Any more ordering or devm vs. non-devm mixing violations here? If so,
> > can you please link me to an example or some docs where I ould figure
> > out what it is I'm still doing wrong?
>
> Device managed resources are attached to the instance of the device
> object and removed in the order they have been attached to, but with
> the caveat that they have no clue about non-managed calls in between.
> Now you may figure out what happens. Ex.:
>
> probe()
> A
> devm_B
> C
> devm_D
>
> remove()
> un_C
> un_A
>
> WRONG!
For the sake of comprehensivity of the examples the right one(s) depicted below:
->probe()
1)
devm_A
devm_B
C
D
2)
A
B
C
D
3)
devm_A
devm_B
devm_C
devm_D
Hint:
`git log --no-merges --grep devm_add_action_or_reset`
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface
2022-01-07 20:58 ` Andy Shevchenko
@ 2022-01-07 23:15 ` Gabriel L. Somlo
0 siblings, 0 replies; 13+ messages in thread
From: Gabriel L. Somlo @ 2022-01-07 23:15 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Rob Herring, devicetree, Ulf Hansson, linux-mmc, Karol Gugala,
Mateusz Holenko, Kamil Rakoczy, mdudek, Paul Mackerras,
Joel Stanley, Stafford Horne, Geert Uytterhoeven,
david.abdurachmanov, Florent Kermarrec, Randy Dunlap,
Linux Kernel Mailing List
On Fri, Jan 07, 2022 at 10:58:40PM +0200, Andy Shevchenko wrote:
> On Fri, Jan 7, 2022 at 10:50 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> > On Fri, Jan 7, 2022 at 7:08 PM Gabriel L. Somlo <gsomlo@gmail.com> wrote:
> > > On Fri, Jan 07, 2022 at 12:06:16PM -0500, Gabriel Somlo wrote:
>
> ...
>
> > > Any more ordering or devm vs. non-devm mixing violations here? If so,
> > > can you please link me to an example or some docs where I ould figure
> > > out what it is I'm still doing wrong?
> >
> > Device managed resources are attached to the instance of the device
> > object and removed in the order they have been attached to, but with
> > the caveat that they have no clue about non-managed calls in between.
> > Now you may figure out what happens. Ex.:
> >
> > probe()
> > A
> > devm_B
> > C
> > devm_D
> >
> > remove()
> > un_C
> > un_A
> >
> > WRONG!
>
> For the sake of comprehensivity of the examples the right one(s) depicted below:
>
> ->probe()
>
> 1)
> devm_A
> devm_B
> C
> D
>
> 2)
> A
> B
> C
> D
>
> 3)
> devm_A
> devm_B
> devm_C
> devm_D
>
> Hint:
> `git log --no-merges --grep devm_add_action_or_reset`
Thanks again!
As far as I can tell, I *meant* (but failed to) use `devm_request_irq()`,
which would then have justified the absence of `free_irq()` on the
probe() function's error path!
Similarly, I would no longer have to call it during remove() either:
diff --git a/drivers/mmc/host/litex_mmc.c b/drivers/mmc/host/litex_mmc.c
index d96da0bcba55..38952f169a27 100644
--- a/drivers/mmc/host/litex_mmc.c
+++ b/drivers/mmc/host/litex_mmc.c
@@ -486,8 +486,8 @@ static int litex_mmc_irq_init(struct litex_mmc_host *host)
if (IS_ERR(host->sdirq))
return PTR_ERR(host->sdirq);
- ret = request_irq(host->irq, litex_mmc_interrupt, 0,
- "litex-mmc", host->mmc);
+ 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;
@@ -626,20 +626,16 @@ static int litex_mmc_probe(struct platform_device *pdev)
return 0;
err:
- if (host->irq > 0)
- free_irq(host->irq, mmc);
mmc_free_host(mmc);
return ret;
}
static int litex_mmc_remove(struct platform_device *pdev)
{
- struct litex_mmc_host *host = dev_get_drvdata(&pdev->dev);
+ struct litex_mmc_host *host = platform_get_drvdata(pdev);
struct mmc_host *mmc = host->mmc;
mmc_remove_host(mmc);
- if (host->irq > 0)
- free_irq(host->irq, mmc);
mmc_free_host(mmc);
return 0;
I'll send out v8 shortly, hopeuflly with all ordering and devm-ness
issues fixed.
Thanks,
--Gabriel
^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface
2022-01-07 20:50 ` Andy Shevchenko
2022-01-07 20:58 ` Andy Shevchenko
@ 2022-01-07 21:23 ` Gabriel L. Somlo
[not found] ` <CAHp75VfMJyeF4dpz63TqZv9UCMBWmQu0U622SOV7wLmn7Qm0mQ@mail.gmail.com>
1 sibling, 1 reply; 13+ messages in thread
From: Gabriel L. Somlo @ 2022-01-07 21:23 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Rob Herring, devicetree, Ulf Hansson, linux-mmc, Karol Gugala,
Mateusz Holenko, Kamil Rakoczy, mdudek, Paul Mackerras,
Joel Stanley, Stafford Horne, Geert Uytterhoeven,
david.abdurachmanov, Florent Kermarrec, Randy Dunlap,
Linux Kernel Mailing List
On Fri, Jan 07, 2022 at 10:50:02PM +0200, Andy Shevchenko wrote:
> > > + .of_match_table = of_match_ptr(litex_match),
> >
> > You said "Wrong usage of of_match_ptr()" here, and all I have to go by
> > is a bunch of other `drivers/mmc/host/*.c` files that use it in a
> > similar way, so can you please clarify and/or provide an example of how
> > to do it properly?
>
> First of all, you have a dependency to OF, try to remove it and
> compile with OF=n and you will immediately see the issue. You may also
> go for `git log --no-merges --grep of_match_ptr` and analyze the
> result.
Ah, grepping for "of_match_ptr" was *never* going to show me the
"right way of using of_match_ptr()" :)
OTOH, grepping for "of_match_table" (and of course the commits
returned by your command line) suggests that I simply should *not*
use it at all, and assign its argument directly to .of_match_table.
Got it, fixed it, thanks!
Now, on to the probe ordering issue... :)
Thanks,
--G
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface
2022-01-07 17:06 ` [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface Gabriel Somlo
2022-01-07 17:08 ` Gabriel L. Somlo
@ 2022-01-07 17:10 ` Gabriel L. Somlo
2022-01-07 20:54 ` Andy Shevchenko
2 siblings, 0 replies; 13+ messages in thread
From: Gabriel L. Somlo @ 2022-01-07 17:10 UTC (permalink / raw)
To: ulf.hansson
Cc: robh+dt, devicetree, linux-kernel, linux-mmc, kgugala, mholenko,
krakoczy, mdudek, paulus, joel, shorne, geert,
david.abdurachmanov, florent, rdunlap, andy.shevchenko
Hi Ulf,
Couple of follow-up questions inline, below:
On Fri, Jan 07, 2022 at 12:06:16PM -0500, Gabriel Somlo 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@antmicro.com>
> Signed-off-by: Kamil Rakoczy <krakoczy@antmicro.com>
> Co-developed-by: Maciej Dudek <mdudek@internships.antmicro.com>
> Signed-off-by: Maciej Dudek <mdudek@internships.antmicro.com>
> Co-developed-by: Paul Mackerras <paulus@ozlabs.org>
> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
> Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
> Cc: Mateusz Holenko <mholenko@antmicro.com>
> Cc: Karol Gugala <kgugala@antmicro.com>
> Cc: Joel Stanley <joel@jms.id.au>
> Cc: Stafford Horne <shorne@gmail.com>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: David Abdurachmanov <david.abdurachmanov@sifive.com>
> Cc: Florent Kermarrec <florent@enjoy-digital.fr>
> Reviewed-by: Joel Stanley <joel@jms.id.au>
> ---
>
> 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 | 10 +
> drivers/mmc/host/Makefile | 1 +
> drivers/mmc/host/litex_mmc.c | 670 +++++++++++++++++++++++++++++++++++
> 3 files changed, 681 insertions(+)
> create mode 100644 drivers/mmc/host/litex_mmc.c
>
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 5af8494c31b5..a24561b74f18 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -1093,3 +1093,13 @@ config MMC_OWL
>
> config MMC_SDHCI_EXTERNAL_DMA
> bool
> +
> +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.
> +
> + 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..3719115850d9
> --- /dev/null
> +++ b/drivers/mmc/host/litex_mmc.c
> @@ -0,0 +1,670 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * 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>
> + *
> + */
> +
> +#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/module.h>
> +#include <linux/mmc/host.h>
> +#include <linux/mmc/mmc.h>
> +#include <linux/mmc/sd.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.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)
I'd like to hear back from you on what you think of this, and, more
importantly, the place it's referenced further below...
> +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);
> +
> + /* Ensure bus width will be set (again) upon card (re)insertion */
> + if (ret == 0)
> + host->is_bus_width_set = false;
> +
> + return ret;
> +}
> +
> +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 = request_irq(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 int litex_mmc_probe(struct platform_device *pdev)
> +{
> + 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), &pdev->dev);
> + if (!mmc)
> + return -ENOMEM;
> +
> + host = mmc_priv(mmc);
> + host->mmc = mmc;
> + host->dev = pdev;
> +
> + /* Initialize clock source */
> + clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(clk)) {
> + ret = dev_err_probe(&pdev->dev,
> + PTR_ERR(clk), "can't get clock\n");
> + goto err;
> + }
> + 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(&pdev->dev, DMA_BIT_MASK(64));
> + if (ret)
> + goto err;
> +
> + host->buf_size = mmc->max_req_size * 2;
> + host->buffer = dmam_alloc_coherent(&pdev->dev, host->buf_size,
> + &host->dma, GFP_DMA);
> + if (host->buffer == NULL) {
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + host->sdphy = devm_platform_ioremap_resource_byname(pdev, "phy");
> + if (IS_ERR(host->sdphy)) {
> + ret = PTR_ERR(host->sdphy);
> + goto err;
> + }
> +
> + host->sdcore = devm_platform_ioremap_resource_byname(pdev, "core");
> + if (IS_ERR(host->sdcore)) {
> + ret = PTR_ERR(host->sdcore);
> + goto err;
> + }
> +
> + host->sdreader = devm_platform_ioremap_resource_byname(pdev, "reader");
> + if (IS_ERR(host->sdreader)) {
> + ret = PTR_ERR(host->sdreader);
> + goto err;
> + }
> +
> + host->sdwriter = devm_platform_ioremap_resource_byname(pdev, "writer");
> + if (IS_ERR(host->sdwriter)) {
> + ret = PTR_ERR(host->sdwriter);
> + goto err;
> + }
> +
> + /* 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)
> + goto err;
> +
> + /* Allow full generic 2.7-3.6V range; no software tuning available */
> + mmc->ocr_avail = LITEX_MMC_OCR;
...here. Per the "Part 1 Simplified"/"Physical Layer Simplified Spec."
at https://www.sdcard.org/downloads/pls/ (page 85 of the pdf document),
I'm hard-coding the 2.7-3.6V range as valid, and the hardware offers no
interface for tuning or configuring voltage via software in any way
whatsoever.
IMHO it's cleaner to hardcode something like that in the driver rather
than pretend it's configurable via DTS only to hard-code it *there*
using a (dummy) voltage regulator.
But I'm certainly willing to be educated if you think I'm wrong, so
please let me know.
Thanks much,
--Gabriel
> + 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)
> + goto err;
> +
> + /* 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);
> +
> + ret = mmc_add_host(mmc);
> + if (ret < 0)
> + goto err;
> +
> + return 0;
> +
> +err:
> + if (host->irq > 0)
> + free_irq(host->irq, mmc);
> + mmc_free_host(mmc);
> + return ret;
> +}
> +
> +static int litex_mmc_remove(struct platform_device *pdev)
> +{
> + struct litex_mmc_host *host = dev_get_drvdata(&pdev->dev);
> + struct mmc_host *mmc = host->mmc;
> +
> + mmc_remove_host(mmc);
> + if (host->irq > 0)
> + free_irq(host->irq, mmc);
> + mmc_free_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 = of_match_ptr(litex_match),
> + },
> +};
> +module_platform_driver(litex_mmc_driver);
> +
> +MODULE_DESCRIPTION("LiteX SDCard driver");
> +MODULE_AUTHOR("Antmicro <contact@antmicro.com>");
> +MODULE_AUTHOR("Kamil Rakoczy <krakoczy@antmicro.com>");
> +MODULE_AUTHOR("Maciej Dudek <mdudek@internships.antmicro.com>");
> +MODULE_AUTHOR("Paul Mackerras <paulus@ozlabs.org>");
> +MODULE_AUTHOR("Gabriel Somlo <gsomlo@gmail.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.31.1
>
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface
2022-01-07 17:06 ` [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface Gabriel Somlo
2022-01-07 17:08 ` Gabriel L. Somlo
2022-01-07 17:10 ` Gabriel L. Somlo
@ 2022-01-07 20:54 ` Andy Shevchenko
2022-01-07 21:14 ` Gabriel L. Somlo
2 siblings, 1 reply; 13+ messages in thread
From: Andy Shevchenko @ 2022-01-07 20:54 UTC (permalink / raw)
To: Gabriel Somlo
Cc: Linux Kernel Mailing List, Rob Herring, devicetree, Ulf Hansson,
linux-mmc, Karol Gugala, Mateusz Holenko, Kamil Rakoczy, mdudek,
Paul Mackerras, Joel Stanley, Stafford Horne, Geert Uytterhoeven,
david.abdurachmanov, Florent Kermarrec, Randy Dunlap
On Fri, Jan 7, 2022 at 7:06 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!
...
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * 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>
> + *
I guess I have commented on this and there was no discussion about the
necessity of this blank line. I dunno what else has been ignored, so I
will wait either for the continuation of the discussion (as per v6) or
amending code in v8.
> + */
...
On top of that it might still be the ordering issues in the error path
of ->probe() and in ->remove(). I believe we will likely see v8.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v7 3/3] mmc: Add driver for LiteX's LiteSDCard interface
2022-01-07 20:54 ` Andy Shevchenko
@ 2022-01-07 21:14 ` Gabriel L. Somlo
0 siblings, 0 replies; 13+ messages in thread
From: Gabriel L. Somlo @ 2022-01-07 21:14 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Linux Kernel Mailing List, Rob Herring, devicetree, Ulf Hansson,
linux-mmc, Karol Gugala, Mateusz Holenko, Kamil Rakoczy, mdudek,
Paul Mackerras, Joel Stanley, Stafford Horne, Geert Uytterhoeven,
david.abdurachmanov, Florent Kermarrec, Randy Dunlap
On Fri, Jan 07, 2022 at 10:54:12PM +0200, Andy Shevchenko wrote:
> On Fri, Jan 7, 2022 at 7:06 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!
>
> ...
>
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * 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>
>
> > + *
>
> I guess I have commented on this and there was no discussion about the
> necessity of this blank line. I dunno what else has been ignored, so I
> will wait either for the continuation of the discussion (as per v6) or
> amending code in v8.
Yeah, not sure how that got lost, it "should have" been in v7 already,
but will definitely be in v8... :)
BTW, I also added the `bit.h` include per your explanation, and removed
all the `Cc:` lines from the commit blurb (not sure when it's actually
appropriate to put those in vs. just cc-ing people from `git send-email`,
but I have no strong feelings about it of my own :)
> > + */
>
> ...
>
> On top of that it might still be the ordering issues in the error path
> of ->probe() and in ->remove(). I believe we will likely see v8.
I'll need to follow your bread crumbs on ordering and `of_match_table`
(also in some of the other emails you've sent in this thread),
and will send out v8 once I've made some sense of it all...
Thanks much,
--Gabriel
^ permalink raw reply [flat|nested] 13+ messages in thread