[PATCH v4] mmc: dw_mmc: Allow lower TMOUT value than maximum
From: Mårten Lindahl <hidden>
Date: 2021-11-17 16:09:47
Subsystem:
multimedia card (mmc), secure digital (sd) and sdio subsystem, synopsys designware mmc/sd/sdio driver, the rest · Maintainers:
Ulf Hansson, Jaehoon Chung, Shawn Lin, Linus Torvalds
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 <redacted> --- v2: - Calculate new value before checking boundaries - Include CLKDIV register to get proper value v3: - Use 'if-else' instead of 'goto' - Don't touch response field when maximize data field v4: - Prevent 32bit divider overflow by splitting the operation - Changed %06x to %#08x as suggested by Doug - Rephrased commit msg as suggested by Doug drivers/mmc/host/dw_mmc.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index d977f34f6b55..8e9d33e1b96c 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c@@ -1283,6 +1283,32 @@ 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) +{ + unsigned int clk_div, tmp, tmout; + + 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(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)
@@ -1303,7 +1329,7 @@ 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); }
--
2.20.1