Re: [PATCH v1] Bluetooth: btintel_pcie: Device suspend-resume support added

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Wed, 23 Oct 2024, Paul Menzel wrote:

> [Cc: +Bjorn, +linux-pci]
> 
> Dear Chandra,
> 
> 
> Thank you for the patch.
> 
> First something minor: Should there be a space in your name?
> 
> ChandraShekar → Chandra Shekar
> 
> `git config --global user.name "…"` can configure this for your git setup.
> 
> Also for the summary/title, it’d be great if you used a statement by using a
> verb (in imperative mood):
> 
> Add device suspend-resume support
> 
> or shorter
> 
> Support suspend-resume
> 
> Am 23.10.24 um 13:46 schrieb ChandraShekar:
> > This patch contains the changes in driver to support the suspend and
> > resume i.e move the controller to D3 state when the platform is entering
> > into suspend and move the controller to D0 on resume.
> 
> It’d be great if you elaborated. Please start by the history, since when Intel
> Bluetooth PCIe have been there, and why until now this support was missing.
> 
> Then please describe, what is needed, and what documentation you used to
> implement the support.
> 
> Also, please document, how you tested this, including the log messages, and
> also the time it takes to resume.
> 
> Is it also possible to use Bluetooth as a wakeup source from suspend?
> 
> > Signed-off-by: Kiran K <kiran.k@intel.com>
> > Signed-off-by: ChandraShekar <chandrashekar.devegowda@intel.com>
> > ---
> >   drivers/bluetooth/btintel_pcie.c | 52 ++++++++++++++++++++++++++++++++
> >   drivers/bluetooth/btintel_pcie.h |  4 +++
> >   2 files changed, 56 insertions(+)
> > 
> > diff --git a/drivers/bluetooth/btintel_pcie.c
> > b/drivers/bluetooth/btintel_pcie.c
> > index fd4a8bd056fa..f2c44b9d7328 100644
> > --- a/drivers/bluetooth/btintel_pcie.c
> > +++ b/drivers/bluetooth/btintel_pcie.c
> > @@ -273,6 +273,12 @@ static int btintel_pcie_reset_bt(struct
> > btintel_pcie_data *data)
> >   	return reg == 0 ? 0 : -ENODEV;
> >   }
> >   +static void btintel_pcie_set_persistence_mode(struct btintel_pcie_data
> > *data)
> > +{
> > +	btintel_pcie_set_reg_bits(data, BTINTEL_PCIE_CSR_HW_BOOT_CONFIG,
> > +				  BTINTEL_PCIE_CSR_HW_BOOT_CONFIG_KEEP_ON);
> > +}
> > +
> >   /* This function enables BT function by setting
> > BTINTEL_PCIE_CSR_FUNC_CTRL_MAC_INIT bit in
> >    * BTINTEL_PCIE_CSR_FUNC_CTRL_REG register and wait for MSI-X with
> >    * BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0.
> > @@ -297,6 +303,8 @@ static int btintel_pcie_enable_bt(struct
> > btintel_pcie_data *data)
> >   	 */
> >   	data->boot_stage_cache = 0x0;
> >   +	btintel_pcie_set_persistence_mode(data);
> > +
> >   	/* Set MAC_INIT bit to start primary bootloader */
> >   	reg = btintel_pcie_rd_reg32(data, BTINTEL_PCIE_CSR_FUNC_CTRL_REG);
> >   	reg &= ~(BTINTEL_PCIE_CSR_FUNC_CTRL_FUNC_INIT |
> > @@ -1653,11 +1661,55 @@ static void btintel_pcie_remove(struct pci_dev
> > *pdev)
> >   	pci_set_drvdata(pdev, NULL);
> >   }
> >   +static int btintel_pcie_suspend(struct device *dev)
> > +{
> > +	struct btintel_pcie_data *data;
> > +	int err;
> > +	struct  pci_dev *pdev = to_pci_dev(dev);

Extra space.

> > +
> > +	data = pci_get_drvdata(pdev);
> > +	btintel_pcie_wr_sleep_cntrl(data, BTINTEL_PCIE_STATE_D3_HOT);
> > +	data->gp0_received = false;
> > +	err = wait_event_timeout(data->gp0_wait_q, data->gp0_received,
> > +
> > msecs_to_jiffies(BTINTEL_DEFAULT_INTR_TIMEOUT_MS));
> > +	if (!err) {
> > +		bt_dev_err(data->hdev, "failed to receive gp0 interrupt for
> > suspend");
> 
> Please include the timeout in the message.
> 
> > +		goto fail;
> > +	}
> > +	return 0;
> > +fail:
> > +	return -EBUSY;
> > +}
> > +
> > +static int btintel_pcie_resume(struct device *dev)
> > +{
> > +	struct btintel_pcie_data *data;
> > +	struct  pci_dev *pdev = to_pci_dev(dev);

Ditto.

> > +	int err;

Why's the order inconsistent compared with suspend func local vars?

> > +
> > +	data = pci_get_drvdata(pdev);
> > +	btintel_pcie_wr_sleep_cntrl(data, BTINTEL_PCIE_STATE_D0);
> > +	data->gp0_received = false;
> > +	err = wait_event_timeout(data->gp0_wait_q, data->gp0_received,
> > +
> > msecs_to_jiffies(BTINTEL_DEFAULT_INTR_TIMEOUT_MS));
> > +	if (!err) {
> > +		bt_dev_err(data->hdev, "failed to receive gp0 interrupt for
> > resume");
> 
> Ditto.
> 
> > +		goto fail;
> > +	}
> > +	return 0;
> > +fail:
> > +	return -EBUSY;

Quite much common code here compared with the suspend side. Perhaps a 
helper function would be useful?

> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(btintel_pcie_pm_ops, btintel_pcie_suspend,
> > +		btintel_pcie_resume);
> > +
> >   static struct pci_driver btintel_pcie_driver = {
> >   	.name = KBUILD_MODNAME,
> >   	.id_table = btintel_pcie_table,
> >   	.probe = btintel_pcie_probe,
> >   	.remove = btintel_pcie_remove,
> > +	.driver.pm = &btintel_pcie_pm_ops,
> >   };
> >   module_pci_driver(btintel_pcie_driver);
> >   diff --git a/drivers/bluetooth/btintel_pcie.h
> > b/drivers/bluetooth/btintel_pcie.h
> > index f9aada0543c4..38d0c8ea2b6f 100644
> > --- a/drivers/bluetooth/btintel_pcie.h
> > +++ b/drivers/bluetooth/btintel_pcie.h
> > @@ -8,6 +8,7 @@
> >     /* Control and Status Register(BTINTEL_PCIE_CSR) */
> >   #define BTINTEL_PCIE_CSR_BASE			(0x000)
> > +#define BTINTEL_PCIE_CSR_HW_BOOT_CONFIG		(BTINTEL_PCIE_CSR_BASE
> > + 0x000)
> >   #define BTINTEL_PCIE_CSR_FUNC_CTRL_REG		(BTINTEL_PCIE_CSR_BASE
> > + 0x024)
> >   #define BTINTEL_PCIE_CSR_HW_REV_REG		(BTINTEL_PCIE_CSR_BASE +
> > 0x028)
> >   #define BTINTEL_PCIE_CSR_RF_ID_REG		(BTINTEL_PCIE_CSR_BASE +
> > 0x09C)
> > @@ -48,6 +49,9 @@
> >   #define BTINTEL_PCIE_CSR_MSIX_IVAR_BASE
> > (BTINTEL_PCIE_CSR_MSIX_BASE + 0x0880)
> >   #define BTINTEL_PCIE_CSR_MSIX_IVAR(cause)
> > (BTINTEL_PCIE_CSR_MSIX_IVAR_BASE + (cause))
> >   +/* CSR HW BOOT CONFIG Register */
> > +#define BTINTEL_PCIE_CSR_HW_BOOT_CONFIG_KEEP_ON		(BIT(31))

Extra parenthesis.

-- 
 i.


> > +
> >   /* Causes for the FH register interrupts */
> >   enum msix_fh_int_causes {
> >   	BTINTEL_PCIE_MSIX_FH_INT_CAUSES_0	= BIT(0),	/* cause 0 */