2022-02-09 09:22:36

by Joe Perches

[permalink] [raw]
Subject: Re: [PATCH V6 1/3] platform/x86: Add Intel Software Defined Silicon driver

On Mon, 2022-02-07 at 16:54 -0800, David E. Box wrote:
> Intel Software Defined Silicon (SDSi) is a post manufacturing mechanism for
> activating additional silicon features. Features are enabled through a
> license activation process. The SDSi driver provides a per socket, sysfs
> attribute interface for applications to perform 3 main provisioning
> functions:
[]
> ---
> V6
> - Replace,
> return (ret < 0) ? ret : size;
> with,
> if (ret)
> return ret;
> return size
>
> Besides the style change (suggested by GKH) this fixes a klocwork
> warning.

thanks.

> diff --git a/drivers/platform/x86/intel/sdsi.c b/drivers/platform/x86/intel/sdsi.c

[]

> +/* SDSi mailbox operations must be performed using 64bit mov instructions */
> +static __always_inline void
> +sdsi_memcpy64_toio(u64 __iomem *to, const u64 *from, size_t count_bytes)
> +{
> + size_t count = count_bytes / sizeof(*to);
> + int i;
> +
> + for (i = 0; i < count; i++)
> + writeq(from[i], &to[i]);

Any chance the byte count is not a multiple of sizeof(u64) ?

> +static __always_inline void
> +sdsi_memcpy64_fromio(u64 *to, const u64 __iomem *from, size_t count_bytes)
> +{
> + size_t count = count_bytes / sizeof(*to);
> + int i;
> +
> + for (i = 0; i < count; i++)
> + to[i] = readq(&from[i]);
> +}

here too.

[]

> +static int sdsi_mbox_cmd_read(struct sdsi_priv *priv, struct sdsi_mbox_info *info,
> + size_t *data_size)
> +{
> + struct device *dev = priv->dev;
> + u32 total, loop, eom, status, message_size;
[]
> + if (packet_size > SDSI_SIZE_MAILBOX) {
> + dev_err(dev, "Packet size to large\n");

too

[]
> + /* Message size check is only valid for multi-packet transfers */
> + if (loop && total != message_size)
> + dev_warn(dev, "Read count %d differs from expected count %d\n",

%u

> + total, message_size);


> +static int sdsi_map_mbox_registers(struct sdsi_priv *priv, struct pci_dev *parent,
> + struct disc_table *disc_table, struct resource *disc_res)
> +{
> + u32 access_type = FIELD_GET(DT_ACCESS_TYPE, disc_table->access_info);
> + u32 size = FIELD_GET(DT_SIZE, disc_table->access_info);
> + u32 tbir = FIELD_GET(DT_TBIR, disc_table->offset);
> + u32 offset = DT_OFFSET(disc_table->offset);
> + u32 features_offset;
> + struct resource res = {};
> +
> + /* Starting location of SDSi MMIO region based on access type */
> + switch (access_type) {
> + case ACCESS_TYPE_LOCAL:
> + if (tbir) {
> + dev_err(priv->dev, "Unsupported BAR index %d for access type %d\n",
> + tbir, access_type);

%u here too

[]
> + dev_err(priv->dev, "Unrecognized access_type %d\n", access_type);

and here




2022-02-09 11:55:20

by David E. Box

[permalink] [raw]
Subject: Re: [PATCH V6 1/3] platform/x86: Add Intel Software Defined Silicon driver

On Mon, 2022-02-07 at 17:40 -0800, Joe Perches wrote:
> On Mon, 2022-02-07 at 16:54 -0800, David E. Box wrote:
> > Intel Software Defined Silicon (SDSi) is a post manufacturing mechanism for
> > activating additional silicon features. Features are enabled through a
> > license activation process. The SDSi driver provides a per socket, sysfs
> > attribute interface for applications to perform 3 main provisioning
> > functions:
> []
> > ---
> > V6
> > - Replace,
> > return (ret < 0) ? ret : size;
> > with,
> > if (ret)
> > return ret;
> > return size
> >
> > Besides the style change (suggested by GKH) this fixes a klocwork
> > warning.
>
> thanks.
>
> > diff --git a/drivers/platform/x86/intel/sdsi.c
> > b/drivers/platform/x86/intel/sdsi.c
>
> []
>
> > +/* SDSi mailbox operations must be performed using 64bit mov instructions
> > */
> > +static __always_inline void
> > +sdsi_memcpy64_toio(u64 __iomem *to, const u64 *from, size_t count_bytes)
> > +{
> > + size_t count = count_bytes / sizeof(*to);
> > + int i;
> > +
> > + for (i = 0; i < count; i++)
> > + writeq(from[i], &to[i]);
>
> Any chance the byte count is not a multiple of sizeof(u64) ?

No. The value passed to count_bytes is either u64 or rounded up to sizeof(u64).
But I'd like to know how I could guard against accidentally passing something
different in the future.

Andy had suggested just adding support for 64 bit memcpy io, but I hadn't time
to look at this.

>
> > +static __always_inline void
> > +sdsi_memcpy64_fromio(u64 *to, const u64 __iomem *from, size_t count_bytes)
> > +{
> > + size_t count = count_bytes / sizeof(*to);
> > + int i;
> > +
> > + for (i = 0; i < count; i++)
> > + to[i] = readq(&from[i]);
> > +}
>
> here too.

Same.

>
> []
>
> > +static int sdsi_mbox_cmd_read(struct sdsi_priv *priv, struct sdsi_mbox_info
> > *info,
> > + size_t *data_size)
> > +{
> > + struct device *dev = priv->dev;
> > + u32 total, loop, eom, status, message_size;
> []
> > + if (packet_size > SDSI_SIZE_MAILBOX) {
> > + dev_err(dev, "Packet size to large\n");
>
> too

Sorry, I'm missing the question here. If it's whether packet_size could also not
be a multiple of sizeof(u64) the answer here is yes. But I don't see how that
matters. packet_size is a value read from the hardware. This is just a sanity
check.

>
> []
> > + /* Message size check is only valid for multi-packet transfers */
> > + if (loop && total != message_size)
> > + dev_warn(dev, "Read count %d differs from expected count %d\n",
>
> %u
>
> > + total, message_size);
> > +static int sdsi_map_mbox_registers(struct sdsi_priv *priv, struct pci_dev
> > *parent,
> > + struct disc_table *disc_table, struct
> > resource *disc_res)
> > +{
> > + u32 access_type = FIELD_GET(DT_ACCESS_TYPE, disc_table->access_info);
> > + u32 size = FIELD_GET(DT_SIZE, disc_table->access_info);
> > + u32 tbir = FIELD_GET(DT_TBIR, disc_table->offset);
> > + u32 offset = DT_OFFSET(disc_table->offset);
> > + u32 features_offset;
> > + struct resource res = {};
> > +
> > + /* Starting location of SDSi MMIO region based on access type */
> > + switch (access_type) {
> > + case ACCESS_TYPE_LOCAL:
> > + if (tbir) {
> > + dev_err(priv->dev, "Unsupported BAR index %d for access
> > type %d\n",
> > + tbir, access_type);
>
> %u here too
>
> []
> > + dev_err(priv->dev, "Unrecognized access_type %d\n",
> > access_type);
>
> and here

Ack on the specifier changes. Thanks.

>
>