This is a generic MHI-over-PCI controller driver for MHI only devices
such as QCOM modems. For now it supports registering of Qualcomm SDX55
based PCIe modules with QMI and MBIM channels. Support for data path
(IP) will come in a future additional series.
This work is based on what has been done for ath11k, and channels have
been identified from the downstream driver.
This driver is easily extendable to support other MHI PCI devices.
This is only an RFC for now.
Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
---
drivers/bus/mhi/Kconfig | 7 +
drivers/bus/mhi/Makefile | 1 +
drivers/bus/mhi/controllers/Makefile | 1 +
drivers/bus/mhi/controllers/mhi_pci_common.c | 317 +++++++++++++++++++++++++++
4 files changed, 326 insertions(+)
create mode 100644 drivers/bus/mhi/controllers/Makefile
create mode 100644 drivers/bus/mhi/controllers/mhi_pci_common.c
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index a8bd9bd..030652c 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -12,3 +12,10 @@ config MHI_BUS
communication protocol used by the host processors to control
and communicate with modem devices over a high speed peripheral
bus or shared memory.
+
+config MHI_BUS_PCI
+ tristate "Modem Host Interface (MHI) bus over PCI"
+ depends on MHI_BUS
+ depends on PCI
+ help
+ This driver provides support for MHI controller drivers over PCI.
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 19e6443..2f1a20c 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -1,2 +1,3 @@
# core layer
obj-y += core/
+obj-y += controllers/
diff --git a/drivers/bus/mhi/controllers/Makefile b/drivers/bus/mhi/controllers/Makefile
new file mode 100644
index 0000000..10cd4f9
--- /dev/null
+++ b/drivers/bus/mhi/controllers/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_MHI_BUS_PCI) := mhi_pci_common.o
diff --git a/drivers/bus/mhi/controllers/mhi_pci_common.c b/drivers/bus/mhi/controllers/mhi_pci_common.c
new file mode 100644
index 0000000..a0833b0
--- /dev/null
+++ b/drivers/bus/mhi/controllers/mhi_pci_common.c
@@ -0,0 +1,317 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * MHI PCI driver - MHI over PCI controller driver
+ *
+ * This module is a generic driver for registering pure MHI-over-PCI devices,
+ * such as PCIe QCOM modems.
+ *
+ * Copyright (C) 2020 Linaro Ltd <loic.poulain@xxxxxxxxxx>
+ */
+
+#include <linux/device.h>
+#include <linux/mhi.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
+
+#define MHI_PCI_BAR_NUM 0
+
+enum {
+ EV_RING_0,
+ EV_RING_1,
+ EV_RING_2,
+ EV_RING_3,
+};
+
+struct mhi_pci_dev_info {
+ const struct mhi_controller_config *config;
+ const char *name;
+};
+
+#define MHI_CHANNEL_CONFIG_SIMPLE_TX(cnum, cname, elems, event) \
+ { \
+ .num = cnum, \
+ .name = cname, \
+ .num_elements = elems, \
+ .event_ring = event, \
+ .dir = DMA_TO_DEVICE, \
+ .ee_mask = 0x04, \
+ .pollcfg = 0, \
+ .doorbell = MHI_DB_BRST_DISABLE, \
+ .lpm_notify = false, \
+ .offload_channel = false, \
+ .doorbell_mode_switch = false, \
+ .auto_queue = false, \
+ } \
+
+#define MHI_CHANNEL_CONFIG_SIMPLE_RX(cnum, cname, elems, event) \
+ { \
+ .num = cnum, \
+ .name = cname, \
+ .num_elements = elems, \
+ .event_ring = event, \
+ .dir = DMA_FROM_DEVICE, \
+ .ee_mask = 0x04, \
+ .pollcfg = 0, \
+ .doorbell = MHI_DB_BRST_DISABLE, \
+ .lpm_notify = false, \
+ .offload_channel = false, \
+ .doorbell_mode_switch = false, \
+ .auto_queue = false, \
+ }
+
+#define MHI_EVENT_CONFIG_SIMPLE_CTRL(enum) \
+ { \
+ .num_elements = 64, \
+ .irq_moderation_ms = 5, \
+ .irq = enum, \
+ .priority = 1, \
+ .mode = MHI_DB_BRST_DISABLE, \
+ .data_type = MHI_ER_CTRL, \
+ .hardware_event = false, \
+ .client_managed = false, \
+ .offload_channel = false, \
+ }
+
+#define MHI_EVENT_CONFIG_SIMPLE_DATA(enum) \
+ { \
+ .num_elements = 64, \
+ .irq_moderation_ms = 5, \
+ .irq = enum, \
+ .priority = 1, \
+ .mode = MHI_DB_BRST_DISABLE, \
+ .data_type = MHI_ER_DATA, \
+ .hardware_event = false, \
+ .client_managed = false, \
+ .offload_channel = false, \
+ }
+
+static const struct mhi_channel_config modem_qcom_v1_mhi_channels[] = {
+ MHI_CHANNEL_CONFIG_SIMPLE_TX(12, "MBIM", 4, EV_RING_0),
+ MHI_CHANNEL_CONFIG_SIMPLE_RX(13, "MBIM", 4, EV_RING_0),
+ MHI_CHANNEL_CONFIG_SIMPLE_TX(14, "QMI", 4, EV_RING_0),
+ MHI_CHANNEL_CONFIG_SIMPLE_RX(15, "QMI", 4, EV_RING_0),
+};
+
+static const struct mhi_event_config modem_qcom_v1_mhi_events[] = {
+ /* first ring is control+data ring */
+ MHI_EVENT_CONFIG_SIMPLE_CTRL(EV_RING_0)
+};
+
+static const struct mhi_controller_config modem_qcom_v1_mhi_config = {
+ .max_channels = 128,
+ .timeout_ms = 5000,
+ .num_channels = ARRAY_SIZE(modem_qcom_v1_mhi_channels),
+ .ch_cfg = modem_qcom_v1_mhi_channels,
+ .num_events = ARRAY_SIZE(modem_qcom_v1_mhi_events),
+ .event_cfg = modem_qcom_v1_mhi_events,
+};
+
+static const struct mhi_pci_dev_info mhi_qcom_sdx55_info = {
+ .name = "qcom-sdx55",
+ .config = &modem_qcom_v1_mhi_config
+};
+
+static const struct pci_device_id mhi_pci_id_table[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_QCOM, 0x0306),
+ .driver_data = (kernel_ulong_t) &mhi_qcom_sdx55_info },
+ { }
+};
+MODULE_DEVICE_TABLE(pci, mhi_pci_id_table);
+
+static int mhi_pci_read_reg(struct mhi_controller *mhic, void __iomem *addr,
+ u32 *out)
+{
+ *out = readl(addr);
+ return 0;
+}
+
+static void mhi_pci_write_reg(struct mhi_controller *mhic, void __iomem *addr,
+ u32 val)
+{
+ writel(val, addr);
+}
+
+static void mhi_pci_status_cb(struct mhi_controller *mhi_cntrl,
+ enum mhi_callback cb)
+{
+ return;
+}
+
+static int mhi_pci_claim(struct mhi_controller *mhic)
+{
+ struct pci_dev *pdev = to_pci_dev(mhic->cntrl_dev);
+ int err;
+
+ err = pci_assign_resource(pdev, MHI_PCI_BAR_NUM);
+ if (err) {
+ dev_err(&pdev->dev, "failed to assign pci resource: %d\n", err);
+ return err;
+ }
+
+ err = pcim_enable_device(pdev);
+ if (err) {
+ dev_err(&pdev->dev, "failed to enable pci device: %d\n", err);
+ return err;
+ }
+
+ /* MAP BAR 0 */
+ err = pcim_iomap_regions(pdev, 1 << MHI_PCI_BAR_NUM, pci_name(pdev));
+ if (err) {
+ dev_err(&pdev->dev, "failed to map pci region: %d\n", err);
+ return err;
+ }
+ mhic->regs = pcim_iomap_table(pdev)[MHI_PCI_BAR_NUM];
+
+ err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+ if (err) {
+ dev_err(&pdev->dev, "Cannot set proper DMA mask\n");
+ return err;
+ }
+
+ err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
+ if (err) {
+ dev_err(&pdev->dev, "set consistent dma mask failed\n");
+ return err;
+ }
+
+ pci_set_master(pdev);
+
+ return 0;
+}
+
+static int mhi_pci_get_irqs(struct mhi_controller *mhic,
+ const struct mhi_controller_config *mhic_config)
+{
+ struct pci_dev *pdev = to_pci_dev(mhic->cntrl_dev);
+ int num_vectors, i;
+ int *irq;
+
+ /* Alloc one MSI vector per event ring, ideally... */
+ num_vectors = pci_alloc_irq_vectors(pdev, 1, mhic_config->num_events,
+ PCI_IRQ_MSI);
+ if (num_vectors < 0) {
+ dev_err(&pdev->dev, "Error allocating MSI vectors %d\n",
+ num_vectors);
+ return num_vectors;
+ }
+
+ if (num_vectors < mhic_config->num_events) {
+ dev_warn(&pdev->dev, "Not enough MSI vectors (%d/%d)\n",
+ num_vectors, mhic_config->num_events);
+ /* use shared IRQ */
+ }
+
+ irq = devm_kcalloc(&pdev->dev, mhic_config->num_events, sizeof(int),
+ GFP_KERNEL);
+ if (!irq)
+ return -ENOMEM;
+
+ for (i = 0; i < mhic_config->num_events; i++) {
+ int vector = i >= num_vectors ? (num_vectors - 1) : i;
+
+ irq[i] = pci_irq_vector(pdev, vector);
+ }
+
+ mhic->irq = irq;
+ mhic->nr_irqs = mhic_config->num_events;
+
+ return 0;
+}
+
+static int mhi_pci_runtime_get(struct mhi_controller *mhi_cntrl)
+{
+ /* no PM for now */
+ return 0;
+}
+
+static void mhi_pci_runtime_put(struct mhi_controller *mhi_cntrl)
+{
+ /* no PM for now */
+ return;
+}
+
+static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+ const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info *) id->driver_data;
+ const struct mhi_controller_config *mhic_config;
+ struct mhi_controller *mhic;
+ int err;
+
+ dev_info(&pdev->dev, "MHI PCI device found: %s\n", info->name);
+
+ mhic = devm_kzalloc(&pdev->dev, sizeof(*mhic), GFP_KERNEL);
+ if (!mhic) {
+ dev_err(&pdev->dev, "failed to allocate mhi controller\n");
+ return -ENOMEM;
+ }
+
+ mhic_config = info->config;
+ mhic->cntrl_dev = &pdev->dev;
+ mhic->iova_start = 0;
+ mhic->iova_stop = 0xffffffff;
+ mhic->fw_image = NULL;
+ mhic->edl_image = NULL;
+
+ mhic->read_reg = mhi_pci_read_reg;
+ mhic->write_reg = mhi_pci_write_reg;
+ mhic->status_cb = mhi_pci_status_cb;
+ mhic->runtime_get = mhi_pci_runtime_get;
+ mhic->runtime_put = mhi_pci_runtime_put;
+
+ err = mhi_pci_claim(mhic);
+ if (err)
+ return err;
+
+ err = mhi_pci_get_irqs(mhic, mhic_config);
+ if (err)
+ return err;
+
+ pci_set_drvdata(pdev, mhic);
+
+ err = mhi_register_controller(mhic, mhic_config);
+ if (err) {
+ dev_err(&pdev->dev, "failed to register MHI controller\n");
+ pci_free_irq_vectors(pdev);
+ return err;
+ }
+
+ /* MHI bus does not power up the controller by default */
+ err = mhi_prepare_for_power_up(mhic);
+ if (err) {
+ dev_err(&pdev->dev, "failed to prepare MHI controller\n");
+ return err;
+ }
+
+ err = mhi_sync_power_up(mhic);
+ if (err) {
+ dev_err(&pdev->dev, "failed to power up MHI controller\n");
+ mhi_unprepare_after_power_down(mhic);
+ mhi_unregister_controller(mhic);
+ return err;
+ }
+
+ return 0;
+}
+
+static void mhi_pci_remove(struct pci_dev *pdev)
+{
+ struct mhi_controller *mhic = pci_get_drvdata(pdev);
+
+ mhi_power_down(mhic, true);
+ mhi_unprepare_after_power_down(mhic);
+ mhi_unregister_controller(mhic);
+}
+
+static struct pci_driver mhi_pci_driver = {
+ .name = "mhi-pci",
+ .id_table = mhi_pci_id_table,
+ .probe = mhi_pci_probe,
+ .remove = mhi_pci_remove
+};
+module_pci_driver(mhi_pci_driver);
+
+MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro,org>");
+MODULE_DESCRIPTION("mhi-pci");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1");
--
2.7.4
