@@ -13,6 +13,7 @@
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
+#include <linux/pm_runtime.h>
#include <linux/soundwire/sdw_registers.h>
#include <linux/soundwire/sdw.h>
#include <sound/pcm_params.h>
@@ -50,6 +51,9 @@ MODULE_PARM_DESC(cdns_mcp_int_mask, "Cadence MCP IntMask");
#define CDNS_MCP_CONTROL_BLOCK_WAKEUP BIT(0)
#define CDNS_MCP_CMDCTRL 0x8
+
+#define CDNS_MCP_CMDCTRL_INSERT_PARITY_ERR BIT(2)
+
#define CDNS_MCP_SSPSTAT 0xC
#define CDNS_MCP_FRAME_SHAPE 0x10
#define CDNS_MCP_FRAME_SHAPE_INIT 0x14
@@ -366,6 +370,85 @@ static int cdns_hw_reset(void *data, u64 value)
DEFINE_DEBUGFS_ATTRIBUTE(cdns_hw_reset_fops, NULL, cdns_hw_reset, "%llu\n");
+static int cdns_parity_error_injection(void *data, u64 value)
+{
+ struct sdw_cdns *cdns = data;
+ struct sdw_bus *bus;
+ int ret;
+
+ if (value != 1)
+ return -EINVAL;
+
+ bus = &cdns->bus;
+
+ /*
+ * Resume Master device. If this results in a bus reset, the
+ * Slave devices will re-attach and be re-enumerated.
+ */
+ ret = pm_runtime_get_sync(bus->dev);
+ if (ret < 0 && ret != -EACCES) {
+ dev_err_ratelimited(cdns->dev,
+ "pm_runtime_get_sync failed in %s, ret %d\n",
+ __func__, ret);
+ pm_runtime_put_noidle(bus->dev);
+ return ret;
+ }
+
+ /*
+ * wait long enough for Slave(s) to be in steady state. This
+ * does not need to be super precise.
+ */
+ msleep(200);
+
+ /*
+ * Take the bus lock here to make sure that any bus transactions
+ * will be queued while we inject a parity error on a dummy read
+ */
+ mutex_lock(&bus->bus_lock);
+
+ /* program hardware to inject parity error */
+ cdns_updatel(cdns, CDNS_MCP_CMDCTRL,
+ CDNS_MCP_CMDCTRL_INSERT_PARITY_ERR,
+ CDNS_MCP_CMDCTRL_INSERT_PARITY_ERR);
+
+ /* commit changes */
+ cdns_updatel(cdns, CDNS_MCP_CONFIG_UPDATE,
+ CDNS_MCP_CONFIG_UPDATE_BIT,
+ CDNS_MCP_CONFIG_UPDATE_BIT);
+
+ /* do a broadcast dummy read to avoid bus clashes */
+ ret = sdw_bread_no_pm_unlocked(&cdns->bus, 0xf, SDW_SCP_DEVID_0);
+ dev_info(cdns->dev, "parity error injection, read: %d\n", ret);
+
+ /* program hardware to disable parity error */
+ cdns_updatel(cdns, CDNS_MCP_CMDCTRL,
+ CDNS_MCP_CMDCTRL_INSERT_PARITY_ERR,
+ 0);
+
+ /* commit changes */
+ cdns_updatel(cdns, CDNS_MCP_CONFIG_UPDATE,
+ CDNS_MCP_CONFIG_UPDATE_BIT,
+ CDNS_MCP_CONFIG_UPDATE_BIT);
+
+ /* Continue bus operation with parity error injection disabled */
+ mutex_unlock(&bus->bus_lock);
+
+ /* Userspace changed the hardware state behind the kernel's back */
+ add_taint(TAINT_USER, LOCKDEP_STILL_OK);
+
+ /*
+ * allow Master device to enter pm_runtime suspend. This may
+ * also result in Slave devices suspending.
+ */
+ pm_runtime_mark_last_busy(bus->dev);
+ pm_runtime_put_autosuspend(bus->dev);
+
+ return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(cdns_parity_error_fops, NULL,
+ cdns_parity_error_injection, "%llu\n");
+
/**
* sdw_cdns_debugfs_init() - Cadence debugfs init
* @cdns: Cadence instance
@@ -377,6 +460,9 @@ void sdw_cdns_debugfs_init(struct sdw_cdns *cdns, struct dentry *root)
debugfs_create_file("cdns-hw-reset", 0200, root, cdns,
&cdns_hw_reset_fops);
+
+ debugfs_create_file("cdns-parity-error-injection", 0200, root, cdns,
+ &cdns_parity_error_fops);
}
EXPORT_SYMBOL_GPL(sdw_cdns_debugfs_init);