soundwire: intel/cadence: fix startup sequence

[ Upstream commit 49ea07d33d9a32c17e18b322e789507280ceb2a3 ]

Multiple changes squashed in single patch to avoid tick-tock effect
and avoid breaking compilation/bisect

1. Per the hardware documentation, all changes to MCP_CONFIG,
MCP_CONTROL, MCP_CMDCTRL and MCP_PHYCTRL need to be validated with a
self-clearing write to MCP_CONFIG_UPDATE. Add a helper and do the
update when the CONFIG is changed.

2. Move interrupt enable after interrupt handler registration

3. Add a new helper to start the hardware bus reset with maximum duration
to make sure the Slave(s) correctly detect the reset pattern and to
ensure electrical conflicts can be resolved.

4. flush command FIFOs

Better error handling will be provided after interrupt disable is
provided in follow-up patches.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191022235448.17586-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 502ed4ec8f070a7c398f2b5fa959408608e8ac02..e3d06330d125847961d68e055dff6bf8cef88553 100644 (file)
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -231,6 +231,22 @@ static int cdns_clear_bit(struct sdw_cdns *cdns, int offset, u32 value)
        return -EAGAIN;
 }
 
+/*
+ * all changes to the MCP_CONFIG, MCP_CONTROL, MCP_CMDCTRL and MCP_PHYCTRL
+ * need to be confirmed with a write to MCP_CONFIG_UPDATE
+ */
+static int cdns_update_config(struct sdw_cdns *cdns)
+{
+       int ret;
+
+       ret = cdns_clear_bit(cdns, CDNS_MCP_CONFIG_UPDATE,
+                            CDNS_MCP_CONFIG_UPDATE_BIT);
+       if (ret < 0)
+               dev_err(cdns->dev, "Config update timedout\n");
+
+       return ret;
+}
+
 /*
  * debugfs
  */
@@ -752,7 +768,38 @@ EXPORT_SYMBOL(sdw_cdns_thread);
 /*
  * init routines
  */
-static int _cdns_enable_interrupt(struct sdw_cdns *cdns)
+
+/**
+ * sdw_cdns_exit_reset() - Program reset parameters and start bus operations
+ * @cdns: Cadence instance
+ */
+int sdw_cdns_exit_reset(struct sdw_cdns *cdns)
+{
+       /* program maximum length reset to be safe */
+       cdns_updatel(cdns, CDNS_MCP_CONTROL,
+                    CDNS_MCP_CONTROL_RST_DELAY,
+                    CDNS_MCP_CONTROL_RST_DELAY);
+
+       /* use hardware generated reset */
+       cdns_updatel(cdns, CDNS_MCP_CONTROL,
+                    CDNS_MCP_CONTROL_HW_RST,
+                    CDNS_MCP_CONTROL_HW_RST);
+
+       /* enable bus operations with clock and data */
+       cdns_updatel(cdns, CDNS_MCP_CONFIG,
+                    CDNS_MCP_CONFIG_OP,
+                    CDNS_MCP_CONFIG_OP_NORMAL);
+
+       /* commit changes */
+       return cdns_update_config(cdns);
+}
+EXPORT_SYMBOL(sdw_cdns_exit_reset);
+
+/**
+ * sdw_cdns_enable_interrupt() - Enable SDW interrupts and update config
+ * @cdns: Cadence instance
+ */
+int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns)
 {
        u32 mask;
 
@@ -784,24 +831,8 @@ static int _cdns_enable_interrupt(struct sdw_cdns *cdns)
 
        cdns_writel(cdns, CDNS_MCP_INTMASK, mask);
 
-       return 0;
-}
-
-/**
- * sdw_cdns_enable_interrupt() - Enable SDW interrupts and update config
- * @cdns: Cadence instance
- */
-int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns)
-{
-       int ret;
-
-       _cdns_enable_interrupt(cdns);
-       ret = cdns_clear_bit(cdns, CDNS_MCP_CONFIG_UPDATE,
-                            CDNS_MCP_CONFIG_UPDATE_BIT);
-       if (ret < 0)
-               dev_err(cdns->dev, "Config update timedout\n");
-
-       return ret;
+       /* commit changes */
+       return cdns_update_config(cdns);
 }
 EXPORT_SYMBOL(sdw_cdns_enable_interrupt);
 
@@ -975,6 +1006,10 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
        cdns_writel(cdns, CDNS_MCP_SSP_CTRL0, CDNS_DEFAULT_SSP_INTERVAL);
        cdns_writel(cdns, CDNS_MCP_SSP_CTRL1, CDNS_DEFAULT_SSP_INTERVAL);
 
+       /* flush command FIFOs */
+       cdns_updatel(cdns, CDNS_MCP_CONTROL, CDNS_MCP_CONTROL_CMD_RST,
+                    CDNS_MCP_CONTROL_CMD_RST);
+
        /* Set cmd accept mode */
        cdns_updatel(cdns, CDNS_MCP_CONTROL, CDNS_MCP_CONTROL_CMD_ACCEPT,
                     CDNS_MCP_CONTROL_CMD_ACCEPT);
@@ -997,13 +1032,10 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
        /* Set cmd mode for Tx and Rx cmds */
        val &= ~CDNS_MCP_CONFIG_CMD;
 
-       /* Set operation to normal */
-       val &= ~CDNS_MCP_CONFIG_OP;
-       val |= CDNS_MCP_CONFIG_OP_NORMAL;
-
        cdns_writel(cdns, CDNS_MCP_CONFIG, val);
 
-       return 0;
+       /* commit changes */
+       return cdns_update_config(cdns);
 }
 EXPORT_SYMBOL(sdw_cdns_init);
 

diff --git a/drivers/soundwire/cadence_master.h b/drivers/soundwire/cadence_master.h
index 0b72b70947352620a79d31d77e483f82e303a8fb..1a67728c5000f63fa5ca9bee3051fbb926e4691c 100644 (file)
--- a/drivers/soundwire/cadence_master.h
+++ b/drivers/soundwire/cadence_master.h
@@ -161,6 +161,7 @@ irqreturn_t sdw_cdns_thread(int irq, void *dev_id);
 int sdw_cdns_init(struct sdw_cdns *cdns);
 int sdw_cdns_pdi_init(struct sdw_cdns *cdns,
                      struct sdw_cdns_stream_config config);
+int sdw_cdns_exit_reset(struct sdw_cdns *cdns);
 int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns);
 
 #ifdef CONFIG_DEBUG_FS

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 243af8198d1c61baf357b8f318c33dad22667f06..a2da04946f0b4e47e33a2e183f370c1338dbf2ba 100644 (file)
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -1050,8 +1050,6 @@ static int intel_probe(struct platform_device *pdev)
        if (ret)
                goto err_init;
 
-       ret = sdw_cdns_enable_interrupt(&sdw->cdns);
-
        /* Read the PDI config and initialize cadence PDI */
        intel_pdi_init(sdw, &config);
        ret = sdw_cdns_pdi_init(&sdw->cdns, config);
@@ -1069,6 +1067,18 @@ static int intel_probe(struct platform_device *pdev)
                goto err_init;
        }
 
+       ret = sdw_cdns_enable_interrupt(&sdw->cdns);
+       if (ret < 0) {
+               dev_err(sdw->cdns.dev, "cannot enable interrupts\n");
+               goto err_init;
+       }
+
+       ret = sdw_cdns_exit_reset(&sdw->cdns);
+       if (ret < 0) {
+               dev_err(sdw->cdns.dev, "unable to exit bus reset sequence\n");
+               goto err_init;
+       }
+
        /* Register DAIs */
        ret = intel_register_dai(sdw);
        if (ret) {