From: Loic Poulain loic.poulain@linaro.org
[ Upstream commit e3e5e6508fc1c0e98a5a264853713dd30a60e5e5 ]
The wake_db register presence is highly speculative and can fuze MHI devices. Indeed, currently the wake_db register address is defined at entry 127 of the 'Channel doorbell array', thus writing to this address is equivalent to ringing the doorbell for channel 127, causing trouble with some devics (e.g. SDX24 based modems) that get an unexpected channel 127 doorbell interrupt.
This change fixes that issue by setting wake get/put as no-op for pci_generic devices. The wake device sideband mechanism seems really specific to each device, and is AFAIK not defined by the MHI spec.
It also removes zeroing initialization of wake_db register during MMIO initialization, the register being set via wake_get/put accessors few cycles later during M0 transition.
Signed-off-by: Loic Poulain loic.poulain@linaro.org Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Link: https://lore.kernel.org/r/1614971808-22156-4-git-send-email-loic.poulain@lin... Signed-off-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/bus/mhi/core/init.c | 2 -- drivers/bus/mhi/pci_generic.c | 18 ++++++++++++++++++ 2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c index be4eebb0971b..bae8e0da2c6f 100644 --- a/drivers/bus/mhi/core/init.c +++ b/drivers/bus/mhi/core/init.c @@ -508,8 +508,6 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl)
/* Setup wake db */ mhi_cntrl->wake_db = base + val + (8 * MHI_DEV_WAKE_DB); - mhi_write_reg(mhi_cntrl, mhi_cntrl->wake_db, 4, 0); - mhi_write_reg(mhi_cntrl, mhi_cntrl->wake_db, 0, 0); mhi_cntrl->wake_set = false;
/* Setup channel db address for each channel in tre_ring */ diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c index 20673a4b4a3c..356c19ce4bbf 100644 --- a/drivers/bus/mhi/pci_generic.c +++ b/drivers/bus/mhi/pci_generic.c @@ -230,6 +230,21 @@ static void mhi_pci_status_cb(struct mhi_controller *mhi_cntrl, } }
+static void mhi_pci_wake_get_nop(struct mhi_controller *mhi_cntrl, bool force) +{ + /* no-op */ +} + +static void mhi_pci_wake_put_nop(struct mhi_controller *mhi_cntrl, bool override) +{ + /* no-op */ +} + +static void mhi_pci_wake_toggle_nop(struct mhi_controller *mhi_cntrl) +{ + /* no-op */ +} + static bool mhi_pci_is_alive(struct mhi_controller *mhi_cntrl) { struct pci_dev *pdev = to_pci_dev(mhi_cntrl->cntrl_dev); @@ -433,6 +448,9 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) mhi_cntrl->status_cb = mhi_pci_status_cb; mhi_cntrl->runtime_get = mhi_pci_runtime_get; mhi_cntrl->runtime_put = mhi_pci_runtime_put; + mhi_cntrl->wake_get = mhi_pci_wake_get_nop; + mhi_cntrl->wake_put = mhi_pci_wake_put_nop; + mhi_cntrl->wake_toggle = mhi_pci_wake_toggle_nop;
err = mhi_pci_claim(mhi_cntrl, info->bar_num, DMA_BIT_MASK(info->dma_data_width)); if (err)