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Date: Thu, 11 Mar 2021 13:13:51 +0200
From: Adrian Hunter <adrian.hunter@...el.com>
To: Jisheng Zhang <Jisheng.Zhang@...aptics.com>,
Ulf Hansson <ulf.hansson@...aro.org>
Cc: linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mmc: sdhci: Use "mmc" directly rather than "host->mmc"
On 11/03/21 11:40 am, Jisheng Zhang wrote:
> Clean up the code to use the "mmc" directly instead of "host->mmc".
> If the code sits in hot code path, this clean up also brings trvial
> performance improvement. Take the sdhci_post_req() for example:
>
> before the patch:
> ...
> 8d0: a9be7bfd stp x29, x30, [sp, #-32]!
> 8d4: 910003fd mov x29, sp
> 8d8: f9000bf3 str x19, [sp, #16]
> 8dc: f9400833 ldr x19, [x1, #16]
> 8e0: b9404261 ldr w1, [x19, #64]
> 8e4: 34000161 cbz w1, 910 <sdhci_post_req+0x50>
> 8e8: f9424400 ldr x0, [x0, #1160]
> 8ec: d2800004 mov x4, #0x0 // #0
> 8f0: b9401a61 ldr w1, [x19, #24]
> 8f4: b9403262 ldr w2, [x19, #48]
> 8f8: f9400000 ldr x0, [x0]
> 8fc: f278003f tst x1, #0x100
> 900: f9401e61 ldr x1, [x19, #56]
> 904: 1a9f17e3 cset w3, eq // eq = none
> 908: 11000463 add w3, w3, #0x1
> 90c: 94000000 bl 0 <dma_unmap_sg_attrs>
> ...
>
> After the patch:
> ...
> 8d0: a9be7bfd stp x29, x30, [sp, #-32]!
> 8d4: 910003fd mov x29, sp
> 8d8: f9000bf3 str x19, [sp, #16]
> 8dc: f9400833 ldr x19, [x1, #16]
> 8e0: b9404261 ldr w1, [x19, #64]
> 8e4: 34000141 cbz w1, 90c <sdhci_post_req+0x4c>
> 8e8: b9401a61 ldr w1, [x19, #24]
> 8ec: d2800004 mov x4, #0x0 // #0
> 8f0: b9403262 ldr w2, [x19, #48]
> 8f4: f9400000 ldr x0, [x0]
> 8f8: f278003f tst x1, #0x100
> 8fc: f9401e61 ldr x1, [x19, #56]
> 900: 1a9f17e3 cset w3, eq // eq = none
> 904: 11000463 add w3, w3, #0x1
> 908: 94000000 bl 0 <dma_unmap_sg_attrs>
> ...
>
> We saved one ldr instruction: "ldr x0, [x0, #1160]"
>
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@...aptics.com>
Acked-by: Adrian Hunter <adrian.hunter@...el.com>
> ---
> drivers/mmc/host/sdhci.c | 33 ++++++++++++++++-----------------
> 1 file changed, 16 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 2d73407ee52e..b1afabab9cae 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -907,7 +907,7 @@ static void sdhci_calc_sw_timeout(struct sdhci_host *host,
>
> if (data) {
> blksz = data->blksz;
> - freq = host->mmc->actual_clock ? : host->clock;
> + freq = mmc->actual_clock ? : host->clock;
> transfer_time = (u64)blksz * NSEC_PER_SEC * (8 / bus_width);
> do_div(transfer_time, freq);
> /* multiply by '2' to account for any unknowns */
> @@ -2269,14 +2269,14 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>
> if (host->quirks & SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK &&
> host->clock) {
> - host->timeout_clk = host->mmc->actual_clock ?
> - host->mmc->actual_clock / 1000 :
> + host->timeout_clk = mmc->actual_clock ?
> + mmc->actual_clock / 1000 :
> host->clock / 1000;
> - host->mmc->max_busy_timeout =
> + mmc->max_busy_timeout =
> host->ops->get_max_timeout_count ?
> host->ops->get_max_timeout_count(host) :
> 1 << 27;
> - host->mmc->max_busy_timeout /= host->timeout_clk;
> + mmc->max_busy_timeout /= host->timeout_clk;
> }
> }
>
> @@ -2399,7 +2399,7 @@ static int sdhci_get_cd(struct mmc_host *mmc)
> return 0;
>
> /* If nonremovable, assume that the card is always present. */
> - if (!mmc_card_is_removable(host->mmc))
> + if (!mmc_card_is_removable(mmc))
> return 1;
>
> /*
> @@ -2489,14 +2489,14 @@ void sdhci_enable_sdio_irq(struct mmc_host *mmc, int enable)
> unsigned long flags;
>
> if (enable)
> - pm_runtime_get_noresume(host->mmc->parent);
> + pm_runtime_get_noresume(mmc->parent);
>
> spin_lock_irqsave(&host->lock, flags);
> sdhci_enable_sdio_irq_nolock(host, enable);
> spin_unlock_irqrestore(&host->lock, flags);
>
> if (!enable)
> - pm_runtime_put_noidle(host->mmc->parent);
> + pm_runtime_put_noidle(mmc->parent);
> }
> EXPORT_SYMBOL_GPL(sdhci_enable_sdio_irq);
>
> @@ -2837,7 +2837,7 @@ int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
> goto out;
> }
>
> - host->mmc->retune_period = tuning_count;
> + mmc->retune_period = tuning_count;
>
> if (host->tuning_delay < 0)
> host->tuning_delay = opcode == MMC_SEND_TUNING_BLOCK;
> @@ -2886,11 +2886,10 @@ static void sdhci_enable_preset_value(struct sdhci_host *host, bool enable)
> static void sdhci_post_req(struct mmc_host *mmc, struct mmc_request *mrq,
> int err)
> {
> - struct sdhci_host *host = mmc_priv(mmc);
> struct mmc_data *data = mrq->data;
>
> if (data->host_cookie != COOKIE_UNMAPPED)
> - dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
> + dma_unmap_sg(mmc_dev(mmc), data->sg, data->sg_len,
> mmc_get_dma_dir(data));
>
> data->host_cookie = COOKIE_UNMAPPED;
> @@ -2941,9 +2940,9 @@ static void sdhci_card_event(struct mmc_host *mmc)
> /* Check sdhci_has_requests() first in case we are runtime suspended */
> if (sdhci_has_requests(host) && !present) {
> pr_err("%s: Card removed during transfer!\n",
> - mmc_hostname(host->mmc));
> + mmc_hostname(mmc));
> pr_err("%s: Resetting controller.\n",
> - mmc_hostname(host->mmc));
> + mmc_hostname(mmc));
>
> sdhci_do_reset(host, SDHCI_RESET_CMD);
> sdhci_do_reset(host, SDHCI_RESET_DATA);
> @@ -3675,7 +3674,7 @@ int sdhci_resume_host(struct sdhci_host *host)
> host->ops->enable_dma(host);
> }
>
> - if ((host->mmc->pm_flags & MMC_PM_KEEP_POWER) &&
> + if ((mmc->pm_flags & MMC_PM_KEEP_POWER) &&
> (host->quirks2 & SDHCI_QUIRK2_HOST_OFF_CARD_ON)) {
> /* Card keeps power but host controller does not */
> sdhci_init(host, 0);
> @@ -3683,7 +3682,7 @@ int sdhci_resume_host(struct sdhci_host *host)
> host->clock = 0;
> mmc->ops->set_ios(mmc, &mmc->ios);
> } else {
> - sdhci_init(host, (host->mmc->pm_flags & MMC_PM_KEEP_POWER));
> + sdhci_init(host, (mmc->pm_flags & MMC_PM_KEEP_POWER));
> }
>
> if (host->irq_wake_enabled) {
> @@ -3691,7 +3690,7 @@ int sdhci_resume_host(struct sdhci_host *host)
> } else {
> ret = request_threaded_irq(host->irq, sdhci_irq,
> sdhci_thread_irq, IRQF_SHARED,
> - mmc_hostname(host->mmc), host);
> + mmc_hostname(mmc), host);
> if (ret)
> return ret;
> }
> @@ -4378,7 +4377,7 @@ int sdhci_setup_host(struct sdhci_host *host)
>
> if ((host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION) &&
> mmc_card_is_removable(mmc) &&
> - mmc_gpio_get_cd(host->mmc) < 0)
> + mmc_gpio_get_cd(mmc) < 0)
> mmc->caps |= MMC_CAP_NEEDS_POLL;
>
> if (!IS_ERR(mmc->supply.vqmmc)) {
>
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