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mmc: dw_mmc: Allow lower TMOUT value than maximum 

The TMOUT register is always set with a full value for every transfer,
which (with a 200MHz clock) will give a full DRTO of ~84 milliseconds.
This is normally good enough to complete the request, but setting a full
value makes it impossible to test shorter timeouts, when for example
testing data read times on different SD cards.

Add a function to set any value smaller than the maximum of 0xFFFFFF.

Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Link: https://lore.kernel.org/r/20211119155337.14341-1-marten.lindahl@axis.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Mårten Lindahl 2021-11-19 16:53:37 +01:00 committed by Ulf Hansson
parent 76bfc7ccc2
commit 6a8c2018e8
1 changed files with 28 additions and 1 deletions
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29
drivers/mmc/host/dw_mmc.c
View File

@ -1284,6 +1284,33 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
mci_writel(host, CTYPE, (slot->ctype << slot->id));
}
static void dw_mci_set_data_timeout(struct dw_mci *host,
unsigned int timeout_ns)
{
u32 clk_div, tmout;
u64 tmp;
clk_div = (mci_readl(host, CLKDIV) & 0xFF) * 2;
if (clk_div == 0)
clk_div = 1;
tmp = DIV_ROUND_UP_ULL((u64)timeout_ns * host->bus_hz, NSEC_PER_SEC);
tmp = DIV_ROUND_UP_ULL(tmp, clk_div);
/* TMOUT[7:0] (RESPONSE_TIMEOUT) */
tmout = 0xFF; /* Set maximum */
/* TMOUT[31:8] (DATA_TIMEOUT) */
if (!tmp || tmp > 0xFFFFFF)
tmout |= (0xFFFFFF << 8);
else
tmout |= (tmp & 0xFFFFFF) << 8;
mci_writel(host, TMOUT, tmout);
dev_dbg(host->dev, "timeout_ns: %u => TMOUT[31:8]: 0x%#08x",
timeout_ns, tmout >> 8);
}
static void __dw_mci_start_request(struct dw_mci *host,
struct dw_mci_slot *slot,
struct mmc_command *cmd)
@ -1304,7 +1331,7 @@ static void __dw_mci_start_request(struct dw_mci *host,
data = cmd->data;
if (data) {
mci_writel(host, TMOUT, 0xFFFFFFFF);
dw_mci_set_data_timeout(host, data->timeout_ns);
mci_writel(host, BYTCNT, data->blksz*data->blocks);
mci_writel(host, BLKSIZ, data->blksz);
}