net: ipa: request IPA register values be retained

BugLink: https://bugs.launchpad.net/bugs/1969857
commit 34a081761e4e3c35381cbfad609ebae2962fe2f8 upstream.

In some cases, the IPA hardware needs to request the always-on
subsystem (AOSS) to coordinate with the IPA microcontroller to
retain IPA register values at power collapse.  This is done by
issuing a QMP request to the AOSS microcontroller.  A similar
request ondoes that request.

We must get and hold the "QMP" handle early, because we might get
back EPROBE_DEFER for that.  But the actual request should be sent
while we know the IPA clock is active, and when we know the
microcontroller is operational.

Fixes: 1aac309d3207 ("net: ipa: use autosuspend")
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/net/ipa/ipa_power.c b/drivers/net/ipa/ipa_power.c
index b1c6c0fcb654f69e363af2e497a0d75fe87a02b2..f2989aac47a62f5944560fddb0465e3b3d7e7671 100644 (file)
--- a/drivers/net/ipa/ipa_power.c
+++ b/drivers/net/ipa/ipa_power.c
@@ -11,6 +11,8 @@
 #include <linux/pm_runtime.h>
 #include <linux/bitops.h>
 
+#include "linux/soc/qcom/qcom_aoss.h"
+
 #include "ipa.h"
 #include "ipa_power.h"
 #include "ipa_endpoint.h"
@@ -64,6 +66,7 @@ enum ipa_power_flag {
  * struct ipa_power - IPA power management information
  * @dev:               IPA device pointer
  * @core:              IPA core clock
+ * @qmp:               QMP handle for AOSS communication
  * @spinlock:          Protects modem TX queue enable/disable
  * @flags:             Boolean state flags
  * @interconnect_count:        Number of elements in interconnect[]
@@ -72,6 +75,7 @@ enum ipa_power_flag {
 struct ipa_power {
        struct device *dev;
        struct clk *core;
+       struct qmp *qmp;
        spinlock_t spinlock;    /* used with STOPPED/STARTED power flags */
        DECLARE_BITMAP(flags, IPA_POWER_FLAG_COUNT);
        u32 interconnect_count;
@@ -382,6 +386,47 @@ void ipa_power_modem_queue_active(struct ipa *ipa)
        clear_bit(IPA_POWER_FLAG_STARTED, ipa->power->flags);
 }
 
+static int ipa_power_retention_init(struct ipa_power *power)
+{
+       struct qmp *qmp = qmp_get(power->dev);
+
+       if (IS_ERR(qmp)) {
+               if (PTR_ERR(qmp) == -EPROBE_DEFER)
+                       return -EPROBE_DEFER;
+
+               /* We assume any other error means it's not defined/needed */
+               qmp = NULL;
+       }
+       power->qmp = qmp;
+
+       return 0;
+}
+
+static void ipa_power_retention_exit(struct ipa_power *power)
+{
+       qmp_put(power->qmp);
+       power->qmp = NULL;
+}
+
+/* Control register retention on power collapse */
+void ipa_power_retention(struct ipa *ipa, bool enable)
+{
+       static const char fmt[] = "{ class: bcm, res: ipa_pc, val: %c }";
+       struct ipa_power *power = ipa->power;
+       char buf[36];   /* Exactly enough for fmt[]; size a multiple of 4 */
+       int ret;
+
+       if (!power->qmp)
+               return;         /* Not needed on this platform */
+
+       (void)snprintf(buf, sizeof(buf), fmt, enable ? '1' : '0');
+
+       ret = qmp_send(power->qmp, buf, sizeof(buf));
+       if (ret)
+               dev_err(power->dev, "error %d sending QMP %sable request\n",
+                       ret, enable ? "en" : "dis");
+}
+
 int ipa_power_setup(struct ipa *ipa)
 {
        int ret;
@@ -438,12 +483,18 @@ ipa_power_init(struct device *dev, const struct ipa_power_data *data)
        if (ret)
                goto err_kfree;
 
+       ret = ipa_power_retention_init(power);
+       if (ret)
+               goto err_interconnect_exit;
+
        pm_runtime_set_autosuspend_delay(dev, IPA_AUTOSUSPEND_DELAY);
        pm_runtime_use_autosuspend(dev);
        pm_runtime_enable(dev);
 
        return power;
 
+err_interconnect_exit:
+       ipa_interconnect_exit(power);
 err_kfree:
        kfree(power);
 err_clk_put:
@@ -460,6 +511,7 @@ void ipa_power_exit(struct ipa_power *power)
 
        pm_runtime_disable(dev);
        pm_runtime_dont_use_autosuspend(dev);
+       ipa_power_retention_exit(power);
        ipa_interconnect_exit(power);
        kfree(power);
        clk_put(clk);

diff --git a/drivers/net/ipa/ipa_power.h b/drivers/net/ipa/ipa_power.h
index 2151805d7fbb0fa40dec0a0984827fb152a6d6f1..6f84f057a2095b92d869ba0c8d626ab85b9c9c34 100644 (file)
--- a/drivers/net/ipa/ipa_power.h
+++ b/drivers/net/ipa/ipa_power.h
@@ -40,6 +40,13 @@ void ipa_power_modem_queue_wake(struct ipa *ipa);
  */
 void ipa_power_modem_queue_active(struct ipa *ipa);
 
+/**
+ * ipa_power_retention() - Control register retention on power collapse
+ * @ipa:       IPA pointer
+ * @enable:    Whether retention should be enabled or disabled
+ */
+void ipa_power_retention(struct ipa *ipa, bool enable);
+
 /**
  * ipa_power_setup() - Set up IPA power management
  * @ipa:       IPA pointer

diff --git a/drivers/net/ipa/ipa_uc.c b/drivers/net/ipa/ipa_uc.c
index 856e55a080a7f07ee2024b3d1932ba73893a8400..fe11910518d95f1ee352eb1ce1cf8cdb60d91c45 100644 (file)
--- a/drivers/net/ipa/ipa_uc.c
+++ b/drivers/net/ipa/ipa_uc.c
@@ -11,6 +11,7 @@
 
 #include "ipa.h"
 #include "ipa_uc.h"
+#include "ipa_power.h"
 
 /**
  * DOC:  The IPA embedded microcontroller
@@ -154,6 +155,7 @@ static void ipa_uc_response_hdlr(struct ipa *ipa, enum ipa_irq_id irq_id)
        case IPA_UC_RESPONSE_INIT_COMPLETED:
                if (ipa->uc_powered) {
                        ipa->uc_loaded = true;
+                       ipa_power_retention(ipa, true);
                        pm_runtime_mark_last_busy(dev);
                        (void)pm_runtime_put_autosuspend(dev);
                        ipa->uc_powered = false;
@@ -184,6 +186,9 @@ void ipa_uc_deconfig(struct ipa *ipa)
 
        ipa_interrupt_remove(ipa->interrupt, IPA_IRQ_UC_1);
        ipa_interrupt_remove(ipa->interrupt, IPA_IRQ_UC_0);
+       if (ipa->uc_loaded)
+               ipa_power_retention(ipa, false);
+
        if (!ipa->uc_powered)
                return;