[PATCH 2/8] mhi: pci-generic: Perform hard reset on remove

[Loic Poulain <loic.poulain@linaro.org>]

Ensure that the device is hard-reset on remove to restore its initial
state and avoid further issues on subsequent probe.

This has been tested with Telit FN980m module.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
---
 drivers/bus/mhi/pci_generic.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
index 13a7e4f..09c6b26 100644
--- a/drivers/bus/mhi/pci_generic.c
+++ b/drivers/bus/mhi/pci_generic.c
@@ -15,6 +15,8 @@
 
 #define MHI_PCI_DEFAULT_BAR_NUM 0
 
+#define DEV_RESET_REG (0xB0)
+
 /**
  * struct mhi_pci_dev_info - MHI PCI device specific information
  * @config: MHI controller configuration
@@ -166,6 +168,11 @@ static void mhi_pci_status_cb(struct mhi_controller *mhi_cntrl,
 	/* Nothing to do for now */
 }
 
+static inline void mhi_pci_reset(struct mhi_controller *mhi_cntrl)
+{
+	writel(1, mhi_cntrl->regs + DEV_RESET_REG);
+}
+
 static int mhi_pci_claim(struct mhi_controller *mhi_cntrl,
 			 unsigned int bar_num, u64 dma_mask)
 {
@@ -329,6 +336,10 @@ static void mhi_pci_remove(struct pci_dev *pdev)
 	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);
+
 	mhi_free_controller(mhi_cntrl);
 }
 
-- 
2.7.4