Messages in this thread | | | Date | Thu, 2 Mar 2023 15:51:46 -0600 | Subject | Re: [PATCH v2 7/9] crypto: ccp: Add support for ringing a platform doorbell | From | Tom Lendacky <> |
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On 3/2/23 13:42, Mario Limonciello wrote: > Some platforms support using a doorbell to communicate. Export > this feature for other drivers to utilize as well. > > Link: https://lore.kernel.org/linux-i2c/20220916131854.687371-3-jsd@semihalf.com/ > Suggested-by: Jan Dabros <jsd@semihalf.com> > Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> > --- > v1->v2: > * New patch > --- > drivers/crypto/ccp/platform-access.c | 47 ++++++++++++++++++++++++++++ > drivers/crypto/ccp/sp-dev.h | 1 + > include/linux/psp-platform-access.h | 15 +++++++++ > include/linux/psp.h | 3 ++ > 4 files changed, 66 insertions(+) > > diff --git a/drivers/crypto/ccp/platform-access.c b/drivers/crypto/ccp/platform-access.c > index af3a1e97abfe..0763389a2814 100644 > --- a/drivers/crypto/ccp/platform-access.c > +++ b/drivers/crypto/ccp/platform-access.c > @@ -135,6 +135,53 @@ int psp_send_platform_access_msg(enum psp_platform_access_msg msg, > } > EXPORT_SYMBOL_GPL(psp_send_platform_access_msg); > > +int psp_ring_platform_doorbell(enum psp_platform_access_msg msg) > +{ > + struct psp_device *psp = psp_get_master_device(); > + struct psp_platform_access_device *pa_dev; > + u32 __iomem *drbl; > + u32 drbl_reg;
Lets spell out doorbell for these two variable names.
> + int ret; > + > + if (!psp || !psp->platform_access_data) > + return -ENODEV; > + > + pa_dev = psp->platform_access_data; > + drbl = psp->io_regs + pa_dev->vdata->doorbell_reg; > + > + if (!drbl) > + return -ENODEV;
This will be non-zero because psp->io_regs will always be non-zero. Maybe you meant to check the actual pa_dev->vdata->doorbell_reg value?
I think you should squash this and patch #9 together so that patch #8 just works right away.
> + > + mutex_lock(&pa_dev->mutex);
Does the doorbell register operate independently from the other registers (C2PMSG_28 - C2PMSG_30)? If it does, you could probably just introduce a doorbell mutex.
> + > + if (check_recovery(drbl)) { > + dev_dbg(psp->dev, "in recovery\n");
Maybe a bit more info as to what is "in recovery" (that goes for patch #4, too) or just prefix it with "doorbell" (and "platform" in #4) since you now have duplicated messages.
> + ret = -EBUSY; > + goto unlock; > + } > + > + if (wait_cmd(drbl)) { > + dev_dbg(psp->dev, "not done processing command\n");
Ditto.
Thanks, Tom
> + ret = -EBUSY; > + goto unlock; > + } > + > + drbl_reg = FIELD_PREP(PSP_DRBL_MSG, msg) | PSP_DRBL_RING; > + iowrite32(drbl_reg, drbl); > + > + if (wait_cmd(drbl)) { > + ret = -ETIMEDOUT; > + goto unlock; > + } > + > + ret = 0; > +unlock: > + mutex_unlock(&pa_dev->mutex); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(psp_ring_platform_doorbell); > + > void platform_access_dev_destroy(struct psp_device *psp) > { > struct psp_platform_access_device *pa_dev = psp->platform_access_data; > diff --git a/drivers/crypto/ccp/sp-dev.h b/drivers/crypto/ccp/sp-dev.h > index 5ec6c219a731..87c0b9350bc2 100644 > --- a/drivers/crypto/ccp/sp-dev.h > +++ b/drivers/crypto/ccp/sp-dev.h > @@ -54,6 +54,7 @@ struct tee_vdata { > }; > > struct platform_access_vdata { > + const unsigned int doorbell_reg; > const unsigned int cmdresp_reg; > const unsigned int cmdbuff_addr_lo_reg; > const unsigned int cmdbuff_addr_hi_reg; > diff --git a/include/linux/psp-platform-access.h b/include/linux/psp-platform-access.h > index f5a03cd11f10..1e1d0e077cec 100644 > --- a/include/linux/psp-platform-access.h > +++ b/include/linux/psp-platform-access.h > @@ -35,6 +35,21 @@ struct psp_request { > */ > int psp_send_platform_access_msg(enum psp_platform_access_msg, struct psp_request *req); > > +/** > + * psp_ring_platform_doorbell() - Ring platform doorbell > + * > + * This function is intended to be used by drivers outside of ccp to ring the > + * platform doorbell with a message. > + * > + * Returns: > + * 0: success > + * -%EBUSY: mailbox in recovery or in use > + * -%ENODEV: driver not bound with PSP device > + * -%ETIMEDOUT: request timed out > + * -%EIO: unknown error (see kernel log) > + */ > +int psp_ring_platform_doorbell(enum psp_platform_access_msg); > + > /** > * psp_check_platform_access_status() - Checks whether platform features is ready > * > diff --git a/include/linux/psp.h b/include/linux/psp.h > index d3424790a70e..92e60aeef21e 100644 > --- a/include/linux/psp.h > +++ b/include/linux/psp.h > @@ -23,4 +23,7 @@ > #define PSP_CMDRESP_RECOVERY BIT(30) > #define PSP_CMDRESP_RESP BIT(31) > > +#define PSP_DRBL_MSG PSP_CMDRESP_CMD > +#define PSP_DRBL_RING BIT(0) > + > #endif /* __PSP_H */
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