[PATCH] mmc: sdhci: Use "mmc" directly rather than "host->mmc"

Jisheng Zhang
2021-03-11T09:41:42Z

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@synaptics.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)) {
--
2.30.2