drivers/mmc/core- Add better CRC control

CruelKernel · Mar 26, 2020 · e1e637c · e1e637c
1 parent 573e9b9
commit e1e637c
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Showing 2 changed files with 21 additions and 3 deletions.
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
@@ -68,9 +68,27 @@ static const unsigned freqs[] = { 400000, 300000, 200000, 100000 };
  * Enabling software CRCs on the data blocks can be a significant (30%)
  * performance cost, and for other reasons may not always be desired.
  * So we allow it it to be disabled.
+
+ * 
+ * SysFs interface :
+ *
+ * /sys/module/mmc_core/parameters/crc
+ *
+ * Enable / Disable CRC 
+ * 
+ * echo N > /sys/module/mmc_core/parameters/crc (Disabled) or
+ * echo 0 > /sys/module/mmc_core/parameters/crc (Disabled)
+ *
+ * echo Y > /sys/module/mmc_core/parameters/crc (Enlabled) or
+ * echo 1 > /sys/module/mmc_core/parameters/crc (Enabled)
  */
-bool use_spi_crc = 1;
-module_param(use_spi_crc, bool, 0);
+
+int use_spi_crc = 0;
+EXPORT_SYMBOL(use_spi_crc);
+module_param_named(crc, use_spi_crc, int, 0644);
+MODULE_PARM_DESC(
+	crc,
+	"Enable/disable CRC");
 
 static int mmc_schedule_delayed_work(struct delayed_work *work,
 				     unsigned long delay)

diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
@@ -81,7 +81,7 @@ int mmc_attach_sd(struct mmc_host *host);
 int mmc_attach_sdio(struct mmc_host *host);
 
 /* Module parameters */
-extern bool use_spi_crc;
+extern int use_spi_crc;
 
 /* Debugfs information for hosts and cards */
 void mmc_add_host_debugfs(struct mmc_host *host);