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SubjectRe: [RFC PATCH V3 12/21] mmc: sdhci: UHS-II support, add hooks for additional operations
Date
On 10/07/20 2:10 pm, Ben Chuang wrote:
> From: Ben Chuang <ben.chuang@genesyslogic.com.tw>
>
> In this commit, UHS-II related operations will be called via a function
> pointer array, sdhci_uhs2_ops, in order to make UHS-II support as
> a kernel module.
> This array will be initialized only if CONFIG_MMC_SDHCI_UHS2 is enabled
> and when the UHS-II module is loaded. Otherwise, all the functions
> stay void.
>
> Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> ---
> drivers/mmc/host/sdhci.c | 152 ++++++++++++++++++++++++++++++++++-----
> 1 file changed, 136 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index aaf41954511a..5511649946b9 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -32,8 +32,12 @@
> #include <linux/mmc/card.h>
> #include <linux/mmc/sdio.h>
> #include <linux/mmc/slot-gpio.h>
> +#include <linux/mmc/uhs2.h>

Ideally, we wouldn't need to use any UHS-II definitions in sdhci.c

> +#include <linux/pci.h>

And never PCI. Please remove

>
> #include "sdhci.h"
> +#include "sdhci-uhs2.h"

sdhci-uhs2.h must not be included because the point of having it is to separate UHS-II from SD mode, so please remove

> +#include "sdhci-pci.h"

Also this include must be removed

>
> #define DRIVER_NAME "sdhci"
>
> @@ -45,6 +49,11 @@
>
> #define MAX_TUNING_LOOP 40
>
> +#if IS_ENABLED(CONFIG_MMC_SDHCI_UHS2)
> +struct sdhci_uhs2_ops sdhci_uhs2_ops;
> +EXPORT_SYMBOL_GPL(sdhci_uhs2_ops);
> +#endif

As I mentioned in a previous patch, please add to sdhci_ops instead.

> +
> static unsigned int debug_quirks = 0;
> static unsigned int debug_quirks2;
>
> @@ -1041,8 +1050,11 @@ EXPORT_SYMBOL_GPL(sdhci_set_data_timeout_irq);
>
> void __sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
> {
> + u8 count;
> +
> bool too_big = false;
> - u8 count = sdhci_calc_timeout(host, cmd, &too_big);
> +
> + count = sdhci_calc_timeout(host, cmd, &too_big);

Last 2 chunks do nothing. Please remove

>
> if (too_big &&
> host->quirks2 & SDHCI_QUIRK2_DISABLE_HW_TIMEOUT) {
> @@ -1053,6 +1065,11 @@ void __sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
> }
>
> sdhci_writeb(host, count, SDHCI_TIMEOUT_CONTROL);
> +
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + host->mmc->flags & MMC_UHS2_SUPPORT &&
> + sdhci_uhs2_ops.set_timeout)
> + sdhci_uhs2_ops.set_timeout(host);

This is the kind of thing I want to avoid. We already have a ->set_timeout() callback. I would suggest creating something like:

static void __uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
{
<whatever>
}

void uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
{
if (host->uhs2_mode)
__uhs2_set_timeout(host, cmd);
else
__sdhci_set_timeout(host, cmd);
}
EXPORT_SYMBOL_GPL(uhs2_set_timeout);

Then uhs2 drivers need to set:

.set_timeout = uhs2_set_timeout,

> }
> EXPORT_SYMBOL_GPL(__sdhci_set_timeout);
>
> @@ -1191,7 +1208,14 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
>
> sdhci_set_transfer_irqs(host);
>
> - sdhci_set_block_info(host, data);
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + host->mmc->flags & MMC_UHS2_SUPPORT &&
> + host->mmc->flags & MMC_UHS2_INITIALIZED) {
> + sdhci_writew(host, data->blksz, SDHCI_UHS2_BLOCK_SIZE);
> + sdhci_writew(host, data->blocks, SDHCI_UHS2_BLOCK_COUNT);
> + } else {
> + sdhci_set_block_info(host, data);
> + }

Again, this is what I want to avoid. I would like to have 3 kinds of functions:
- SD mode only
- UHS-II only
- SD functions with no UHS-II code, that can also be used by UHS-II
i.e. I don't want to mix UHS-II code and SD mode code in the same function.

I think sdhci-uhs2.c should provide a request function and a send_command function.
I would start by removing everything you may not need, and then see if you have any problems.
e.g.

void uhs2_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
struct sdhci_host *host = mmc_priv(mmc);
struct mmc_command *cmd;
unsigned long flags;

if (!host->uhs2_mode) {
sdhci_request(mmc, mrq);
return;
}

spin_lock_irqsave(&host->lock, flags);
uhs2_send_command(host, cmd);
spin_unlock_irqrestore(&host->lock, flags);
}
EXPORT_SYMBOL_GPL(uhs2_request);

For sdhci_prepare_data(), I would factor out the dma part, so

static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
{
struct mmc_data *data = cmd->data;
sdhci_initialize_data(host, data);

sdhci_prepare_dma(host, data);

sdhci_set_block_info(host, data);
}
The you could export sdhci_initialize_data() and sdhci_prepare_dma() for uhs2.

> }
>
> #if IS_ENABLED(CONFIG_MMC_SDHCI_EXTERNAL_DMA)
> @@ -1439,6 +1463,13 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host,
> u16 mode = 0;
> struct mmc_data *data = cmd->data;
>
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + host->mmc->flags & MMC_UHS2_SUPPORT) {
> + if (sdhci_uhs2_ops.set_transfer_mode)
> + sdhci_uhs2_ops.set_transfer_mode(host, cmd);
> + return;
> + }
> +

Once you provide uhs2_request() and uhs2_send_command(), the transfer mode setting can be done in sdhci-uhs2.c

> if (data == NULL) {
> if (host->quirks2 &
> SDHCI_QUIRK2_CLEAR_TRANSFERMODE_REG_BEFORE_CMD) {
> @@ -1570,6 +1601,12 @@ static void __sdhci_finish_data(struct sdhci_host *host, bool sw_data_timeout)
> else
> data->bytes_xfered = data->blksz * data->blocks;
>
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + host->mmc->flags & MMC_UHS2_INITIALIZED) {
> + __sdhci_finish_mrq(host, data->mrq);
> + return;
> + }

At least to start with, I think it would be better to handle UHS-II cmd and data interrupts completely in sdhci-uhs2.c

> +
> /*
> * Need to send CMD12 if -
> * a) open-ended multiblock transfer not using auto CMD12 (no CMD23)
> @@ -1654,7 +1691,8 @@ static bool sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
> sdhci_prepare_data(host, cmd);
> }
>
> - sdhci_writel(host, cmd->arg, SDHCI_ARGUMENT);
> + if (!IS_ENABLED(CONFIG_MMC_SDHCI_UHS2))
> + sdhci_writel(host, cmd->arg, SDHCI_ARGUMENT);

Not needed when instead you provide uhs2_send_command()
>
> sdhci_set_transfer_mode(host, cmd);
>
> @@ -1699,6 +1737,17 @@ static bool sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
> if (host->use_external_dma)
> sdhci_external_dma_pre_transfer(host, cmd);
>
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + (host->mmc->flags & MMC_UHS2_SUPPORT)) {
> + if (sdhci_uhs2_ops.send_command)
> + sdhci_uhs2_ops.send_command(host, cmd);
> +
> + return true;
> + }
> +
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2))
> + sdhci_writel(host, cmd->arg, SDHCI_ARGUMENT);

Not needed when instead you provide uhs2_send_command()

> +
> sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
>
> return true;
> @@ -1780,13 +1829,20 @@ static void sdhci_finish_command(struct sdhci_host *host)
> {
> struct mmc_command *cmd = host->cmd;
>
> - host->cmd = NULL;
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + host->mmc->flags & MMC_UHS2_SUPPORT) {
> + if (sdhci_uhs2_ops.finish_command)
> + sdhci_uhs2_ops.finish_command(host);
> + } else {
> + host->cmd = NULL;
>
> - if (cmd->flags & MMC_RSP_PRESENT) {
> - if (cmd->flags & MMC_RSP_136) {
> - sdhci_read_rsp_136(host, cmd);
> - } else {
> - cmd->resp[0] = sdhci_readl(host, SDHCI_RESPONSE);
> + if (cmd->flags & MMC_RSP_PRESENT) {
> + if (cmd->flags & MMC_RSP_136) {
> + sdhci_read_rsp_136(host, cmd);
> + } else {
> + cmd->resp[0] = sdhci_readl(host,
> + SDHCI_RESPONSE);
> + }

At least to start with, I think it would be better to handle UHS-II cmd and data interrupts completely in sdhci-uhs2.c

> }
> }
>
> @@ -1809,6 +1865,7 @@ static void sdhci_finish_command(struct sdhci_host *host)
> } else if (!(host->quirks & SDHCI_QUIRK_NO_BUSY_IRQ) &&
> cmd == host->data_cmd) {
> /* Command complete before busy is ended */
> + host->cmd = NULL;

host->cmd is set to NULL at the start of this function, so this is not needed.

> return;
> }
> }
> @@ -1828,6 +1885,8 @@ static void sdhci_finish_command(struct sdhci_host *host)
> if (!cmd->data)
> __sdhci_finish_mrq(host, cmd->mrq);
> }
> +
> + host->cmd = NULL;

host->cmd is set to NULL at the start of this function, so this is not needed.

> }
>
> static u16 sdhci_get_preset_value(struct sdhci_host *host)
> @@ -1855,6 +1914,11 @@ static u16 sdhci_get_preset_value(struct sdhci_host *host)
> case MMC_TIMING_MMC_HS400:
> preset = sdhci_readw(host, SDHCI_PRESET_FOR_HS400);
> break;
> +#if IS_ENABLED(CONFIG_MMC_SDHCI_UHS2)

Shouldn't need conditional compilation for this

> + case MMC_TIMING_UHS2:
> + preset = sdhci_readw(host, SDHCI_PRESET_FOR_UHS2);
> + break;
> +#endif
> default:
> pr_warn("%s: Invalid UHS-I mode selected\n",
> mmc_hostname(host->mmc));
> @@ -2095,7 +2159,6 @@ void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
> sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL);
>
> pwr |= SDHCI_POWER_ON;
> -

No white space changes mixed in please

> sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL);
>
> if (host->quirks2 & SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON)
> @@ -2261,6 +2324,7 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> {
> struct sdhci_host *host = mmc_priv(mmc);
> u8 ctrl;
> + u16 ctrl_2;
>
> if (ios->power_mode == MMC_POWER_UNDEFINED)
> return;
> @@ -2287,6 +2351,10 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> sdhci_enable_preset_value(host, false);
>
> if (!ios->clock || ios->clock != host->clock) {
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + ios->timing == MMC_TIMING_UHS2)
> + host->timing = ios->timing;
> +
> host->ops->set_clock(host, ios->clock);
> host->clock = ios->clock;
>
> @@ -2308,6 +2376,18 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> else
> sdhci_set_power(host, ios->power_mode, ios->vdd);
>
> + /* 4.0 host support */
> + if (host->version >= SDHCI_SPEC_400) {
> + /* UHS2 Support */
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + host->mmc->flags & MMC_UHS2_SUPPORT &&
> + host->mmc->caps & MMC_CAP_UHS2) {
> + if (sdhci_uhs2_ops.do_set_ios)
> + sdhci_uhs2_ops.do_set_ios(host, ios);
> + return;
> + }
> + }
> +

Please look at using existing callbacks instead, maybe creating uhs2_set_ios(), uhs2_set_clock(), uhs2_set_power()

> if (host->ops->platform_send_init_74_clocks)
> host->ops->platform_send_init_74_clocks(host, ios->power_mode);
>
> @@ -2331,7 +2411,7 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> }
>
> if (host->version >= SDHCI_SPEC_300) {
> - u16 clk, ctrl_2;
> + u16 clk;
>
> if (!host->preset_enabled) {
> sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
> @@ -3173,11 +3253,19 @@ static bool sdhci_request_done(struct sdhci_host *host)
> /* This is to force an update */
> host->ops->set_clock(host, host->clock);
>
> - /* Spec says we should do both at the same time, but Ricoh
> - controllers do not like that. */
> - sdhci_do_reset(host, SDHCI_RESET_CMD);
> - sdhci_do_reset(host, SDHCI_RESET_DATA);
> -
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + host->mmc->flags & MMC_UHS2_INITIALIZED) {
> + if (sdhci_uhs2_ops.reset)
> + sdhci_uhs2_ops.reset(host,
> + SDHCI_UHS2_SW_RESET_SD);
> + } else {
> + /*
> + * Spec says we should do both at the same time, but
> + * Ricoh controllers do not like that.
> + */
> + sdhci_do_reset(host, SDHCI_RESET_CMD);
> + sdhci_do_reset(host, SDHCI_RESET_DATA);
> + }

Please look at using the existing ->reset() sdhci host op instead.

> host->pending_reset = false;
> }
>
> @@ -3532,6 +3620,13 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id)
> SDHCI_INT_BUS_POWER);
> sdhci_writel(host, mask, SDHCI_INT_STATUS);
>
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + intmask & SDHCI_INT_ERROR &&
> + host->mmc->flags & MMC_UHS2_SUPPORT) {
> + if (sdhci_uhs2_ops.irq)
> + sdhci_uhs2_ops.irq(host);
> + }
> +

Please look at using the existing ->irq() sdhci host op instead

> if (intmask & (SDHCI_INT_CARD_INSERT | SDHCI_INT_CARD_REMOVE)) {
> u32 present = sdhci_readl(host, SDHCI_PRESENT_STATE) &
> SDHCI_CARD_PRESENT;
> @@ -4717,6 +4812,14 @@ int sdhci_setup_host(struct sdhci_host *host)
> /* This may alter mmc->*_blk_* parameters */
> sdhci_allocate_bounce_buffer(host);
>
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + host->version >= SDHCI_SPEC_400 &&
> + sdhci_uhs2_ops.add_host) {
> + ret = sdhci_uhs2_ops.add_host(host, host->caps1);
> + if (ret)
> + goto unreg;
> + }
> +

I think you should look at creating uhs2_add_host() instead

> return 0;
>
> unreg:
> @@ -4738,6 +4841,8 @@ void sdhci_cleanup_host(struct sdhci_host *host)
> {
> struct mmc_host *mmc = host->mmc;
>
> + /* FIXME: Do we have to do some cleanup for UHS2 here? */
> +
> if (!IS_ERR(mmc->supply.vqmmc))
> regulator_disable(mmc->supply.vqmmc);
>
> @@ -4766,6 +4871,14 @@ int __sdhci_add_host(struct sdhci_host *host)
> mmc->cqe_ops = NULL;
> }
>
> + if ((mmc->caps & MMC_CAP_UHS2) && !host->v4_mode) {
> + /* host doesn't want to enable UHS2 support */
> + mmc->caps &= ~MMC_CAP_UHS2;
> + mmc->flags &= ~MMC_UHS2_SUPPORT;
> +
> + /* FIXME: Do we have to do some cleanup here? */
> + }
> +
> host->complete_wq = alloc_workqueue("sdhci", flags, 0);
> if (!host->complete_wq)
> return -ENOMEM;
> @@ -4812,6 +4925,9 @@ int __sdhci_add_host(struct sdhci_host *host)
> unled:
> sdhci_led_unregister(host);
> unirq:
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + sdhci_uhs2_ops.remove_host)
> + sdhci_uhs2_ops.remove_host(host, 0);
> sdhci_do_reset(host, SDHCI_RESET_ALL);
> sdhci_writel(host, 0, SDHCI_INT_ENABLE);
> sdhci_writel(host, 0, SDHCI_SIGNAL_ENABLE);
> @@ -4869,6 +4985,10 @@ void sdhci_remove_host(struct sdhci_host *host, int dead)
>
> sdhci_led_unregister(host);
>
> + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> + sdhci_uhs2_ops.remove_host)
> + sdhci_uhs2_ops.remove_host(host, dead);
> +

I think you should look at creating uhs2_remove_host() instead

> if (!dead)
> sdhci_do_reset(host, SDHCI_RESET_ALL);
>
>

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