Re: [PATCH v2 08/10] firmware: arm_ffa: Add v1.1 get_partition_info support

On Wed, Sep 07, 2022 at 10:38:05AM +0200, Jens Wiklander wrote:

On Fri, Sep 2, 2022 at 2:40 PM Sudeep Holla [off-list ref] wrote:

quoted

FF-A v1.1 adds support to discovery the UUIDs of the partitions that was
missing in v1.0 and which the driver workarounds by using UUIDs supplied
by the ffa_drivers.

Add the v1.1 get_partition_info support and disable the workaround if
the detected FF-A version is greater than v1.0.

Signed-off-by: Sudeep Holla <redacted>
---
 drivers/firmware/arm_ffa/driver.c | 42 +++++++++++++++++++++++++------
 include/linux/arm_ffa.h           |  1 +
 2 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 2532e0f16cc9..dd6ab2f81580 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c

@@ -264,18 +264,24 @@ static int ffa_rxtx_unmap(u16 vm_id)
        return 0;
 }

+#define PARTITION_INFO_GET_RETURN_COUNT_ONLY   BIT(0)
+
 /* buffer must be sizeof(struct ffa_partition_info) * num_partitions */
 static int
 __ffa_partition_info_get(u32 uuid0, u32 uuid1, u32 uuid2, u32 uuid3,
                         struct ffa_partition_info *buffer, int num_partitions)
 {
-       int count;
+       int idx, count, flags = 0, size;
        ffa_value_t partition_info;

+       if (!buffer || !num_partitions) /* Just get the count for now */
+               flags = PARTITION_INFO_GET_RETURN_COUNT_ONLY;
+
        mutex_lock(&drv_info->rx_lock);
        invoke_ffa_fn((ffa_value_t){
                      .a0 = FFA_PARTITION_INFO_GET,
                      .a1 = uuid0, .a2 = uuid1, .a3 = uuid2, .a4 = uuid3,
+                     .a5 = flags,
                      }, &partition_info);

        if (partition_info.a0 == FFA_ERROR) {

@@ -285,8 +291,18 @@ __ffa_partition_info_get(u32 uuid0, u32 uuid1, u32 uuid2, u32 uuid3,

        count = partition_info.a2;

+       if (drv_info->version > FFA_VERSION_1_0) {
+               size = partition_info.a3;
+               if (size > sizeof(*buffer))
+                       size = sizeof(*buffer);

Below when calculating the address in the source buffer with
"drv_info->rx_buffer + idx * size" you should use the size from
partition_info.a3 even if it's larger than sizeof(*buffer). The amount
of bytes to copy looks correct though. Does that make sense?

Good spot, I missed to see that. It makes complete sense. I will fix it.

-- 
Regards,
Sudeep

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