On 2020-11-13 06:59, Loic Poulain wrote:
Add support for resetting the device, reset can be triggered in case
of error or manually via sysfs (/sys/bus/pci/devices/*/reset).
Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
---
drivers/bus/mhi/pci_generic.c | 117
+++++++++++++++++++++++++++++++++++++-----
1 file changed, 104 insertions(+), 13 deletions(-)
diff --git a/drivers/bus/mhi/pci_generic.c
b/drivers/bus/mhi/pci_generic.c
index 0c07cf5..b48c382 100644
--- a/drivers/bus/mhi/pci_generic.c
+++ b/drivers/bus/mhi/pci_generic.c
@@ -8,6 +8,7 @@
* Copyright (C) 2020 Linaro Ltd <loic.poulain@xxxxxxxxxx>
*/
+#include <linux/delay.h>
#include <linux/device.h>
#include <linux/mhi.h>
#include <linux/module.h>
@@ -179,6 +180,16 @@ static const struct pci_device_id
mhi_pci_id_table[] = {
};
MODULE_DEVICE_TABLE(pci, mhi_pci_id_table);
+enum mhi_pci_device_status {
+ MHI_PCI_DEV_STARTED,
+};
+
+struct mhi_pci_device {
+ struct mhi_controller mhi_cntrl;
+ struct pci_saved_state *pci_state;
+ unsigned long status;
+};
+
static int mhi_pci_read_reg(struct mhi_controller *mhi_cntrl,
void __iomem *addr, u32 *out)
{
@@ -203,6 +214,20 @@ static inline void mhi_pci_reset(struct
mhi_controller *mhi_cntrl)
writel(1, mhi_cntrl->regs + DEV_RESET_REG);
}
+static bool mhi_pci_is_alive(struct mhi_controller *mhi_cntrl)
+{
+ struct pci_dev *pdev = to_pci_dev(mhi_cntrl->cntrl_dev);
+ u16 vendor = 0;
+
+ if (pci_read_config_word(pdev, PCI_VENDOR_ID, &vendor))
+ return false;
+
+ if (vendor == (u16) ~0 || vendor == 0)
+ return false;
+
+ return true;
+}
+
static int mhi_pci_claim(struct mhi_controller *mhi_cntrl,
unsigned int bar_num, u64 dma_mask)
{
@@ -298,16 +323,18 @@ 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 *mhi_cntrl_config;
+ struct mhi_pci_device *mhi_pdev;
struct mhi_controller *mhi_cntrl;
int err;
dev_dbg(&pdev->dev, "MHI PCI device found: %s\n", info->name);
- mhi_cntrl = mhi_alloc_controller();
- if (!mhi_cntrl)
Not recommended.
+ mhi_pdev = devm_kzalloc(&pdev->dev, sizeof(*mhi_pdev), GFP_KERNEL);
+ if (!mhi_pdev)
return -ENOMEM;
Why move away from the mhi_alloc_controller/mhi_free_controller pair we
recommended for use?
mhi_cntrl_config = info->config;
+ mhi_cntrl = &mhi_pdev->mhi_cntrl;
mhi_cntrl->cntrl_dev = &pdev->dev;
mhi_cntrl->iova_start = 0;
mhi_cntrl->iova_stop = DMA_BIT_MASK(info->dma_data_width);
@@ -322,17 +349,21 @@ static int mhi_pci_probe(struct pci_dev *pdev,
const struct pci_device_id *id)
err = mhi_pci_claim(mhi_cntrl, info->bar_num,
DMA_BIT_MASK(info->dma_data_width));
if (err)
- goto err_release;
+ return err;
err = mhi_pci_get_irqs(mhi_cntrl, mhi_cntrl_config);
if (err)
- goto err_release;
+ return err;
+
+ pci_set_drvdata(pdev, mhi_pdev);
- pci_set_drvdata(pdev, mhi_cntrl);
+ /* Have stored pci confspace at hand for restore in sudden PCI error
*/
+ pci_save_state(pdev);
+ mhi_pdev->pci_state = pci_store_saved_state(pdev);
err = mhi_register_controller(mhi_cntrl, mhi_cntrl_config);
if (err)
- goto err_release;
+ return err;
/* MHI bus does not power up the controller by default */
err = mhi_prepare_for_power_up(mhi_cntrl);
@@ -347,37 +378,97 @@ static int mhi_pci_probe(struct pci_dev *pdev,
const struct pci_device_id *id)
goto err_unprepare;
}
+ set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);
+
return 0;
err_unprepare:
mhi_unprepare_after_power_down(mhi_cntrl);
err_unregister:
mhi_unregister_controller(mhi_cntrl);
-err_release:
- mhi_free_controller(mhi_cntrl);
Not recommended.
return err;
}
static void mhi_pci_remove(struct pci_dev *pdev)
{
- struct mhi_controller *mhi_cntrl = pci_get_drvdata(pdev);
+ struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
+ struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+
+ if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {
+ mhi_power_down(mhi_cntrl, true);
+ mhi_unprepare_after_power_down(mhi_cntrl);
+ }
- mhi_power_down(mhi_cntrl, true);
- mhi_unprepare_after_power_down(mhi_cntrl);
mhi_unregister_controller(mhi_cntrl);
/* MHI-layer reset could not be enough, always hard-reset the device
*/
mhi_pci_reset(mhi_cntrl);
+}
+
+void mhi_pci_reset_prepare(struct pci_dev *pdev)
+{
+ struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
+ struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+
+ dev_info(&pdev->dev, "reset\n");
- mhi_free_controller(mhi_cntrl);
+ /* Clean up MHI state */
+ if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {
+ mhi_power_down(mhi_cntrl, false);
+ mhi_unprepare_after_power_down(mhi_cntrl);
+ }
+
+ /* cause internal device reset */
+ mhi_pci_reset(mhi_cntrl);
+
+ /* Be sure device reset has been executed */
+ msleep(500);
}
+void mhi_pci_reset_done(struct pci_dev *pdev)
+{
+ struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
+ struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+ int err;
+
+ /* Restore initial known working PCI state */
+ pci_load_saved_state(pdev, mhi_pdev->pci_state);
+ pci_restore_state(pdev);
+
+ /* Is device status available ? */
+ if (!mhi_pci_is_alive(mhi_cntrl)) {
+ dev_err(&pdev->dev, "reset failed\n");
+ return;
+ }
+
+ err = mhi_prepare_for_power_up(mhi_cntrl);
+ if (err) {
+ dev_err(&pdev->dev, "failed to prepare MHI controller\n");
+ return;
+ }
+
+ err = mhi_sync_power_up(mhi_cntrl);
+ if (err) {
+ dev_err(&pdev->dev, "failed to power up MHI controller\n");
+ mhi_unprepare_after_power_down(mhi_cntrl);
+ return;
+ }
+
+ set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);
+}
+
+static const struct pci_error_handlers mhi_pci_err_handler = {
+ .reset_prepare = mhi_pci_reset_prepare,
+ .reset_done = mhi_pci_reset_done,
+};
+
static struct pci_driver mhi_pci_driver = {
.name = "mhi-pci-generic",
.id_table = mhi_pci_id_table,
.probe = mhi_pci_probe,
- .remove = mhi_pci_remove
+ .remove = mhi_pci_remove,
+ .err_handler = &mhi_pci_err_handler,
};
module_pci_driver(mhi_pci_driver);
--
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