Re: [PATCH v4 2/4] fpga: dfl: Add DFHv1 Register Definitions

Ilpo Järvinen
2022-10-21T08:06:22Z

On Thu, 20 Oct 2022, matthew.gerlach@linux.intel.com wrote:

> From: Basheer Ahmed Muddebihal <basheer.ahmed.muddebihal@linux.intel.com>
>
> This patch adds the definitions for DFHv1 header and related register
> bitfields.
>
> Signed-off-by: Basheer Ahmed Muddebihal <basheer.ahmed.muddebihal@linux.intel.com>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> ---
> v4: s/MSIX/MSI_X/g
> move kerneldoc to implementation
> don't change copyright date
>
> v3:
> keep DFHv1 definitions "hidden" in drivers/fpga/dfl.h
>
> v2: clean up whitespace and one line comments
> remove extra space in commit
> use uniform number of digits in constants
> don't change copyright date because of removed content
>
> dfl.h s/MSIX/MSI_X/g move kerneldoc
> ---
> drivers/fpga/dfl.h | 33 +++++++++++++++++++++++++++++++++
> include/linux/dfl.h | 11 +++++++++++
> 2 files changed, 44 insertions(+)
>
> diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
> index 06cfcd5e84bb..45e6e1359a67 100644
> --- a/drivers/fpga/dfl.h
> +++ b/drivers/fpga/dfl.h
> @@ -74,11 +74,44 @@
> #define DFH_REVISION GENMASK_ULL(15, 12) /* Feature revision */
> #define DFH_NEXT_HDR_OFST GENMASK_ULL(39, 16) /* Offset to next DFH */
> #define DFH_EOL BIT_ULL(40) /* End of list */
> +#define DFH_VERSION GENMASK_ULL(59, 52) /* DFH version */
> #define DFH_TYPE GENMASK_ULL(63, 60) /* Feature type */
> #define DFH_TYPE_AFU 1
> #define DFH_TYPE_PRIVATE 3
> #define DFH_TYPE_FIU 4
>
> +/*
> + * DFHv1 Register Offset definitons
> + * In DHFv1, DFH + GUID + CSR_START + CSR_SIZE_GROUP + PARAM_HDR + PARAM_DATA
> + * as common header registers
> + */
> +#define DFHv1_CSR_ADDR 0x18 /* CSR Register start address */
> +#define DFHv1_CSR_SIZE_GRP 0x20 /* Size of Reg Block and Group/tag */
> +#define DFHv1_PARAM_HDR 0x28 /* Optional First Param header */
> +
> +/*
> + * CSR Rel Bit, 1'b0 = relative (offset from feature DFH start),
> + * 1'b1 = absolute (ARM or other non-PCIe use)
> + */
> +#define DFHv1_CSR_ADDR_REL BIT_ULL(0)
> +
> +/* CSR Header Register Bit Definitions */
> +#define DFHv1_CSR_ADDR_MASK GENMASK_ULL(63, 1) /* 63:1 of CSR address */
> +
> +/* CSR SIZE Goup Register Bit Definitions */
> +#define DFHv1_CSR_SIZE_GRP_INSTANCE_ID GENMASK_ULL(15, 0) /* Enumeration instantiated IP */
> +#define DFHv1_CSR_SIZE_GRP_GROUPING_ID GENMASK_ULL(30, 16) /* Group Features/interfaces */
> +#define DFHv1_CSR_SIZE_GRP_HAS_PARAMS BIT_ULL(31) /* Presence of Parameters */
> +#define DFHv1_CSR_SIZE_GRP_SIZE GENMASK_ULL(63, 32) /* Size of CSR Block in bytes */

SIZE -> SZ would remove two letters w/o loss of info (remember to
rename the offset too if you make this change).

> +/* PARAM Header Register Bit Definitions */
> +#define DFHv1_PARAM_HDR_ID GENMASK_ULL(15, 0) /* Id of this Param */
> +#define DFHv1_PARAM_HDR_VERSION GENMASK_ULL(31, 16) /* Version Param */
> +#define DFHv1_PARAM_HDR_NEXT_OFFSET GENMASK_ULL(63, 32) /* Offset of next Param */
> +#define DFHv1_PARAM_HDR_NEXT_EOL BIT_ULL(0)
> +#define DFHv1_PARAM_HDR_NEXT_MASK GENMASK_ULL(1, 0)
> +#define DFHv1_PARAM_DATA 0x08 /* Offset of Param data from Param header */
> +
> /* Next AFU Register Bitfield */
> #define NEXT_AFU_NEXT_DFH_OFST GENMASK_ULL(23, 0) /* Offset to next AFU */
>
> diff --git a/include/linux/dfl.h b/include/linux/dfl.h
> index 431636a0dc78..fea9e16d35b6 100644
> --- a/include/linux/dfl.h
> +++ b/include/linux/dfl.h
> @@ -11,6 +11,17 @@
> #include <linux/device.h>
> #include <linux/mod_devicetable.h>
>
> +#define DFHv1_PARAM_ID_MSI_X 0x1
> +#define DFHv1_PARAM_MSI_X_STARTV 0x0
> +#define DFHv1_PARAM_MSI_X_NUMV 0x4
> +
> +#define DFHv1_PARAM_ID_CLK_FRQ 0x2
> +#define DFHv1_PARAM_ID_FIFO_LEN 0x3
> +
> +#define DFHv1_PARAM_ID_REG_LAYOUT 0x4
> +#define DFHv1_PARAM_ID_REG_WIDTH GENMASK_ULL(63, 32)
> +#define DFHv1_PARAM_ID_REG_SHIFT GENMASK_ULL(31, 0)

Any particular reason why MSI_X parameters are given as offsets and
these REG_LAYOUT ones as bitfields (both are 32-bit)?

The naming here would indicate that DFHv1_PARAM_ID_REG_WIDTH is one of the
parameters but it's part of param data instead. I suppose you'd want
DFHv1_PARAM_REG_LAYOUT_WIDTH instead.

--
i.