Re: [PATCH v2 01/10] xen/arm: ffa: Rework firmware discovery

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi Jens,

> On 21 Oct 2024, at 19:03, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
> 
> Hi Bertrand,
> 
> On Wed, Oct 16, 2024 at 10:32 AM Bertrand Marquis
> <bertrand.marquis@xxxxxxx> wrote:
>> 
>> Rework firmware discovery during probe:
>> - move prints into the probe
>> - rename ffa_version to ffa_fw_version as the variable identifies the
>>  version of the firmware and not the one we support
>> - add error prints when allocation fail during probe
>> 
>> No functional changes.
>> 
>> Signed-off-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
>> ---
>> Changes in v2:
>> - Fix error message when we fail to retrieve ffa_version
>> - Move back printing the firmware version before checking supported
>>  features
>> - Use Warning instead of Info to inform user that FF-A is not supported
>>  in firmware.
>> ---
>> xen/arch/arm/tee/ffa.c | 44 ++++++++++++++++++++++++++----------------
>> 1 file changed, 27 insertions(+), 17 deletions(-)
>> 
>> diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
>> index 022089278e1c..1cc4023135d5 100644
>> --- a/xen/arch/arm/tee/ffa.c
>> +++ b/xen/arch/arm/tee/ffa.c
>> @@ -71,8 +71,8 @@
>> 
>> #include "ffa_private.h"
>> 
>> -/* Negotiated FF-A version to use with the SPMC */
>> -static uint32_t __ro_after_init ffa_version;
>> +/* Negotiated FF-A version to use with the SPMC, 0 if not there or 
>> supported */
>> +static uint32_t __ro_after_init ffa_fw_version;
>> 
>> 
>> /*
>> @@ -105,10 +105,7 @@ static bool ffa_get_version(uint32_t *vers)
>> 
>>     arm_smccc_1_2_smc(&arg, &resp);
>>     if ( resp.a0 == FFA_RET_NOT_SUPPORTED )
>> -    {
>> -        gprintk(XENLOG_ERR, "ffa: FFA_VERSION returned not supported\n");
>>         return false;
>> -    }
>> 
>>     *vers = resp.a0;
>> 
>> @@ -372,7 +369,7 @@ static int ffa_domain_init(struct domain *d)
>>     struct ffa_ctx *ctx;
>>     int ret;
>> 
>> -    if ( !ffa_version )
>> +    if ( !ffa_fw_version )
>>         return -ENODEV;
>>      /*
>>       * We can't use that last possible domain ID or ffa_get_vm_id() would
>> @@ -505,6 +502,9 @@ static bool ffa_probe(void)
>>      */
>>     BUILD_BUG_ON(PAGE_SIZE != FFA_PAGE_SIZE);
>> 
>> +    printk(XENLOG_INFO "ARM FF-A Mediator version %u.%u\n",
>> +           FFA_MY_VERSION_MAJOR, FFA_MY_VERSION_MINOR);
>> +
>>     /*
>>      * psci_init_smccc() updates this value with what's reported by EL-3
>>      * or secure world.
>> @@ -514,22 +514,24 @@ static bool ffa_probe(void)
>>         printk(XENLOG_ERR
>>                "ffa: unsupported SMCCC version %#x (need at least %#x)\n",
>>                smccc_ver, ARM_SMCCC_VERSION_1_2);
>> -        return false;
>> +        goto err_no_fw;
>>     }
>> 
>>     if ( !ffa_get_version(&vers) )
>> -        return false;
>> +    {
>> +        gprintk(XENLOG_ERR, "Cannot retrieve the FFA version\n");
>> +        goto err_no_fw;
>> +    }
>> 
>>     if ( vers < FFA_MIN_SPMC_VERSION || vers > FFA_MY_VERSION )
>>     {
>>         printk(XENLOG_ERR "ffa: Incompatible version %#x found\n", vers);
>> -        return false;
>> +        goto err_no_fw;
>>     }
>> 
>> -    major_vers = (vers >> FFA_VERSION_MAJOR_SHIFT) & FFA_VERSION_MAJOR_MASK;
>> +    major_vers = (vers >> FFA_VERSION_MAJOR_SHIFT)
>> +                 & FFA_VERSION_MAJOR_MASK;
> 
> Spurious change?

Yes, I will fix that in next version.

> 
>>     minor_vers = vers & FFA_VERSION_MINOR_MASK;
>> -    printk(XENLOG_INFO "ARM FF-A Mediator version %u.%u\n",
>> -           FFA_MY_VERSION_MAJOR, FFA_MY_VERSION_MINOR);
> 
> It's not a big deal, but isn't it useful to know which version we're
> at? If it's too much with a separate line, how about adding "(our
> version %u.u%)" at the end of the line below?

This was moved up.

> 
>>     printk(XENLOG_INFO "ARM FF-A Firmware version %u.%u\n",
>>            major_vers, minor_vers);
>> 
>> @@ -546,12 +548,18 @@ static bool ffa_probe(void)
>>          !check_mandatory_feature(FFA_MEM_SHARE_32) ||
>>          !check_mandatory_feature(FFA_MEM_RECLAIM) ||
>>          !check_mandatory_feature(FFA_MSG_SEND_DIRECT_REQ_32) )
>> -        return false;
>> +    {
>> +        printk(XENLOG_ERR "ffa: Mandatory feature not supported by fw\n");
>> +        goto err_no_fw;
>> +    }
>> 
>> -    if ( !ffa_rxtx_init() )
>> -        return false;
>> +    ffa_fw_version = vers;
>> 
>> -    ffa_version = vers;
>> +    if ( !ffa_rxtx_init() )
>> +    {
>> +        printk(XENLOG_ERR "ffa: Error during RXTX buffer init\n");
> 
> With this added, wouldn't it make sense to remove the error print in
> ffa_rxtx_init()?

Definitely, I missed that.
Will fix in v3.

Cheers
Bertrand

> 
> Cheers,
> Jens
> 
>> +        goto err_no_fw;
>> +    }
>> 
>>     if ( !ffa_partinfo_init() )
>>         goto err_rxtx_destroy;
>> @@ -564,7 +572,9 @@ static bool ffa_probe(void)
>> 
>> err_rxtx_destroy:
>>     ffa_rxtx_destroy();
>> -    ffa_version = 0;
>> +err_no_fw:
>> +    ffa_fw_version = 0;
>> +    printk(XENLOG_WARNING "ARM FF-A No firmware support\n");
>> 
>>     return false;
>> }
>> --
>> 2.47.0