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authorAlex Elder <elder@linaro.org>2020-03-05 22:28:28 -0600
committerDavid S. Miller <davem@davemloft.net>2020-03-08 22:07:10 -0700
commit530f9216a9537b58cdc2f967b5cd78f5dafb34c4 (patch)
treef5ffb4c246e3d40c3df558643df1b7ba2146a27d /drivers/net/ipa/ipa_smp2p.c
parenta646d6ec90983204398ac20ee26b80ff3ea0852b (diff)
soc: qcom: ipa: AP/modem communications
This patch implements two forms of out-of-band communication between the AP and modem. - QMI is a mechanism that allows clients running on the AP interact with services running on the modem (and vice-versa). The AP IPA driver uses QMI to communicate with the corresponding IPA driver resident on the modem, to agree on parameters used with the IPA hardware and to ensure both sides are ready before entering operational mode. - SMP2P is a more primitive mechanism available for the modem and AP to communicate with each other. It provides a means for either the AP or modem to interrupt the other, and furthermore, to provide 32 bits worth of information. The IPA driver uses SMP2P to tell the modem what the state of the IPA clock was in the event of a crash. This allows the modem to safely access the IPA hardware (or avoid doing so) when a crash occurs, for example, to access information within the IPA hardware. Signed-off-by: Alex Elder <elder@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ipa/ipa_smp2p.c')
-rw-r--r--drivers/net/ipa/ipa_smp2p.c335
1 files changed, 335 insertions, 0 deletions
diff --git a/drivers/net/ipa/ipa_smp2p.c b/drivers/net/ipa/ipa_smp2p.c
new file mode 100644
index 000000000000..4d33aa7ebfbb
--- /dev/null
+++ b/drivers/net/ipa/ipa_smp2p.c
@@ -0,0 +1,335 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
+ * Copyright (C) 2019-2020 Linaro Ltd.
+ */
+
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/soc/qcom/smem.h>
+#include <linux/soc/qcom/smem_state.h>
+
+#include "ipa_smp2p.h"
+#include "ipa.h"
+#include "ipa_uc.h"
+#include "ipa_clock.h"
+
+/**
+ * DOC: IPA SMP2P communication with the modem
+ *
+ * SMP2P is a primitive communication mechanism available between the AP and
+ * the modem. The IPA driver uses this for two purposes: to enable the modem
+ * to state that the GSI hardware is ready to use; and to communicate the
+ * state of the IPA clock in the event of a crash.
+ *
+ * GSI needs to have early initialization completed before it can be used.
+ * This initialization is done either by Trust Zone or by the modem. In the
+ * latter case, the modem uses an SMP2P interrupt to tell the AP IPA driver
+ * when the GSI is ready to use.
+ *
+ * The modem is also able to inquire about the current state of the IPA
+ * clock by trigging another SMP2P interrupt to the AP. We communicate
+ * whether the clock is enabled using two SMP2P state bits--one to
+ * indicate the clock state (on or off), and a second to indicate the
+ * clock state bit is valid. The modem will poll the valid bit until it
+ * is set, and at that time records whether the AP has the IPA clock enabled.
+ *
+ * Finally, if the AP kernel panics, we update the SMP2P state bits even if
+ * we never receive an interrupt from the modem requesting this.
+ */
+
+/**
+ * struct ipa_smp2p - IPA SMP2P information
+ * @ipa: IPA pointer
+ * @valid_state: SMEM state indicating enabled state is valid
+ * @enabled_state: SMEM state to indicate clock is enabled
+ * @valid_bit: Valid bit in 32-bit SMEM state mask
+ * @enabled_bit: Enabled bit in 32-bit SMEM state mask
+ * @enabled_bit: Enabled bit in 32-bit SMEM state mask
+ * @clock_query_irq: IPA interrupt triggered by modem for clock query
+ * @setup_ready_irq: IPA interrupt triggered by modem to signal GSI ready
+ * @clock_on: Whether IPA clock is on
+ * @notified: Whether modem has been notified of clock state
+ * @disabled: Whether setup ready interrupt handling is disabled
+ * @mutex mutex: Motex protecting ready interrupt/shutdown interlock
+ * @panic_notifier: Panic notifier structure
+*/
+struct ipa_smp2p {
+ struct ipa *ipa;
+ struct qcom_smem_state *valid_state;
+ struct qcom_smem_state *enabled_state;
+ u32 valid_bit;
+ u32 enabled_bit;
+ u32 clock_query_irq;
+ u32 setup_ready_irq;
+ bool clock_on;
+ bool notified;
+ bool disabled;
+ struct mutex mutex;
+ struct notifier_block panic_notifier;
+};
+
+/**
+ * ipa_smp2p_notify() - use SMP2P to tell modem about IPA clock state
+ * @smp2p: SMP2P information
+ *
+ * This is called either when the modem has requested it (by triggering
+ * the modem clock query IPA interrupt) or whenever the AP is shutting down
+ * (via a panic notifier). It sets the two SMP2P state bits--one saying
+ * whether the IPA clock is running, and the other indicating the first bit
+ * is valid.
+ */
+static void ipa_smp2p_notify(struct ipa_smp2p *smp2p)
+{
+ u32 value;
+ u32 mask;
+
+ if (smp2p->notified)
+ return;
+
+ smp2p->clock_on = ipa_clock_get_additional(smp2p->ipa);
+
+ /* Signal whether the clock is enabled */
+ mask = BIT(smp2p->enabled_bit);
+ value = smp2p->clock_on ? mask : 0;
+ qcom_smem_state_update_bits(smp2p->enabled_state, mask, value);
+
+ /* Now indicate that the enabled flag is valid */
+ mask = BIT(smp2p->valid_bit);
+ value = mask;
+ qcom_smem_state_update_bits(smp2p->valid_state, mask, value);
+
+ smp2p->notified = true;
+}
+
+/* Threaded IRQ handler for modem "ipa-clock-query" SMP2P interrupt */
+static irqreturn_t ipa_smp2p_modem_clk_query_isr(int irq, void *dev_id)
+{
+ struct ipa_smp2p *smp2p = dev_id;
+
+ ipa_smp2p_notify(smp2p);
+
+ return IRQ_HANDLED;
+}
+
+static int ipa_smp2p_panic_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct ipa_smp2p *smp2p;
+
+ smp2p = container_of(nb, struct ipa_smp2p, panic_notifier);
+
+ ipa_smp2p_notify(smp2p);
+
+ if (smp2p->clock_on)
+ ipa_uc_panic_notifier(smp2p->ipa);
+
+ return NOTIFY_DONE;
+}
+
+static int ipa_smp2p_panic_notifier_register(struct ipa_smp2p *smp2p)
+{
+ /* IPA panic handler needs to run before modem shuts down */
+ smp2p->panic_notifier.notifier_call = ipa_smp2p_panic_notifier;
+ smp2p->panic_notifier.priority = INT_MAX; /* Do it early */
+
+ return atomic_notifier_chain_register(&panic_notifier_list,
+ &smp2p->panic_notifier);
+}
+
+static void ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p *smp2p)
+{
+ atomic_notifier_chain_unregister(&panic_notifier_list,
+ &smp2p->panic_notifier);
+}
+
+/* Threaded IRQ handler for modem "ipa-setup-ready" SMP2P interrupt */
+static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id)
+{
+ struct ipa_smp2p *smp2p = dev_id;
+
+ mutex_lock(&smp2p->mutex);
+
+ if (!smp2p->disabled) {
+ int ret;
+
+ ret = ipa_setup(smp2p->ipa);
+ if (ret)
+ dev_err(&smp2p->ipa->pdev->dev,
+ "error %d from ipa_setup()\n", ret);
+ smp2p->disabled = true;
+ }
+
+ mutex_unlock(&smp2p->mutex);
+
+ return IRQ_HANDLED;
+}
+
+/* Initialize SMP2P interrupts */
+static int ipa_smp2p_irq_init(struct ipa_smp2p *smp2p, const char *name,
+ irq_handler_t handler)
+{
+ struct device *dev = &smp2p->ipa->pdev->dev;
+ unsigned int irq;
+ int ret;
+
+ ret = platform_get_irq_byname(smp2p->ipa->pdev, name);
+ if (ret <= 0) {
+ dev_err(dev, "DT error %d getting \"%s\" IRQ property\n",
+ ret, name);
+ return ret ? : -EINVAL;
+ }
+ irq = ret;
+
+ ret = request_threaded_irq(irq, NULL, handler, 0, name, smp2p);
+ if (ret) {
+ dev_err(dev, "error %d requesting \"%s\" IRQ\n", ret, name);
+ return ret;
+ }
+
+ return irq;
+}
+
+static void ipa_smp2p_irq_exit(struct ipa_smp2p *smp2p, u32 irq)
+{
+ free_irq(irq, smp2p);
+}
+
+/* Drop the clock reference if it was taken in ipa_smp2p_notify() */
+static void ipa_smp2p_clock_release(struct ipa *ipa)
+{
+ if (!ipa->smp2p->clock_on)
+ return;
+
+ ipa_clock_put(ipa);
+ ipa->smp2p->clock_on = false;
+}
+
+/* Initialize the IPA SMP2P subsystem */
+int ipa_smp2p_init(struct ipa *ipa, bool modem_init)
+{
+ struct qcom_smem_state *enabled_state;
+ struct device *dev = &ipa->pdev->dev;
+ struct qcom_smem_state *valid_state;
+ struct ipa_smp2p *smp2p;
+ u32 enabled_bit;
+ u32 valid_bit;
+ int ret;
+
+ valid_state = qcom_smem_state_get(dev, "ipa-clock-enabled-valid",
+ &valid_bit);
+ if (IS_ERR(valid_state))
+ return PTR_ERR(valid_state);
+ if (valid_bit >= 32) /* BITS_PER_U32 */
+ return -EINVAL;
+
+ enabled_state = qcom_smem_state_get(dev, "ipa-clock-enabled",
+ &enabled_bit);
+ if (IS_ERR(enabled_state))
+ return PTR_ERR(enabled_state);
+ if (enabled_bit >= 32) /* BITS_PER_U32 */
+ return -EINVAL;
+
+ smp2p = kzalloc(sizeof(*smp2p), GFP_KERNEL);
+ if (!smp2p)
+ return -ENOMEM;
+
+ smp2p->ipa = ipa;
+
+ /* These fields are needed by the clock query interrupt
+ * handler, so initialize them now.
+ */
+ mutex_init(&smp2p->mutex);
+ smp2p->valid_state = valid_state;
+ smp2p->valid_bit = valid_bit;
+ smp2p->enabled_state = enabled_state;
+ smp2p->enabled_bit = enabled_bit;
+
+ /* We have enough information saved to handle notifications */
+ ipa->smp2p = smp2p;
+
+ ret = ipa_smp2p_irq_init(smp2p, "ipa-clock-query",
+ ipa_smp2p_modem_clk_query_isr);
+ if (ret < 0)
+ goto err_null_smp2p;
+ smp2p->clock_query_irq = ret;
+
+ ret = ipa_smp2p_panic_notifier_register(smp2p);
+ if (ret)
+ goto err_irq_exit;
+
+ if (modem_init) {
+ /* Result will be non-zero (negative for error) */
+ ret = ipa_smp2p_irq_init(smp2p, "ipa-setup-ready",
+ ipa_smp2p_modem_setup_ready_isr);
+ if (ret < 0)
+ goto err_notifier_unregister;
+ smp2p->setup_ready_irq = ret;
+ }
+
+ return 0;
+
+err_notifier_unregister:
+ ipa_smp2p_panic_notifier_unregister(smp2p);
+err_irq_exit:
+ ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
+err_null_smp2p:
+ ipa->smp2p = NULL;
+ mutex_destroy(&smp2p->mutex);
+ kfree(smp2p);
+
+ return ret;
+}
+
+void ipa_smp2p_exit(struct ipa *ipa)
+{
+ struct ipa_smp2p *smp2p = ipa->smp2p;
+
+ if (smp2p->setup_ready_irq)
+ ipa_smp2p_irq_exit(smp2p, smp2p->setup_ready_irq);
+ ipa_smp2p_panic_notifier_unregister(smp2p);
+ ipa_smp2p_irq_exit(smp2p, smp2p->clock_query_irq);
+ /* We won't get notified any more; drop clock reference (if any) */
+ ipa_smp2p_clock_release(ipa);
+ ipa->smp2p = NULL;
+ mutex_destroy(&smp2p->mutex);
+ kfree(smp2p);
+}
+
+void ipa_smp2p_disable(struct ipa *ipa)
+{
+ struct ipa_smp2p *smp2p = ipa->smp2p;
+
+ if (!smp2p->setup_ready_irq)
+ return;
+
+ mutex_lock(&smp2p->mutex);
+
+ smp2p->disabled = true;
+
+ mutex_unlock(&smp2p->mutex);
+}
+
+/* Reset state tracking whether we have notified the modem */
+void ipa_smp2p_notify_reset(struct ipa *ipa)
+{
+ struct ipa_smp2p *smp2p = ipa->smp2p;
+ u32 mask;
+
+ if (!smp2p->notified)
+ return;
+
+ ipa_smp2p_clock_release(ipa);
+
+ /* Reset the clock enabled valid flag */
+ mask = BIT(smp2p->valid_bit);
+ qcom_smem_state_update_bits(smp2p->valid_state, mask, 0);
+
+ /* Mark the clock disabled for good measure... */
+ mask = BIT(smp2p->enabled_bit);
+ qcom_smem_state_update_bits(smp2p->enabled_state, mask, 0);
+
+ smp2p->notified = false;
+}