Re: [PATCH] hw/misc/pfsoc: add fabric clocks to ioscb

[Philippe Mathieu-Daudé]

Hi Conor,

On 9/11/22 20:08, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
>
> On PolarFire SoC, some peripherals (eg the PCI root port) are clocked by
> "Clock Conditioning Circuitry" in the FPGA. The specific clock depends
> on the FPGA bitstream & can be locked to one particular {D,P}LL - in the
> Icicle Kit Reference Design v2022.09 or later this is/will be the case.
>
> Linux v6.1+ will have a driver for this peripheral and devicetrees that
> previously relied on "fixed-frequency" clock nodes have been switched
> over to clock-controller nodes. The IOSCB region is represented in QEMU,
> but the specific region of it that the CCCs occupy has not so v6.1-rcN
> kernels fail to boot in QEMU.
>
> Add the regions as unimplemented so that the status-quo in terms of boot
> is maintained.
>
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
> The last line there is a white lie. v6.1-rcN has both v2022.09 and
> v2022.10 reference design changes. This patch only accounts for the
> v2022.09 changes. The FPGA design is a moving target and I am not
> really sure how to handle that in QEMU. For v2022.10 a bunch of stuff
> got changed, including the addresses that DDR lies at which I am not
> sure how to handle yet.
>
> That puts my todo list of broken things to:
> - MMC (only direct kernel boot works), pre v2022.09 reference issue

How do you start without 'direct kernel boot'?

> - PCI root port address, address changed in v2022.09 but from a cursory
>    check, I didn't see any PCI support in the first place. It's connected
>    to a FIC, so I think it can just be made into an unimplemented region.
> - DDR address changes, 2022.10 issue. Looks like a straightforward
>    change to hw/riscv/pfsoc.c but I don't think it'll be backwards
>    compatible.
> - hwrng breaks boot. Tipping away at this one, hopefully I'll have a fix
>    for it soon. Need to implement the irq side of the mailbox for it.
>
> I'll send some more patches as I work through them.
>
>   hw/misc/mchp_pfsoc_ioscb.c         | 6 ++++++
>   include/hw/misc/mchp_pfsoc_ioscb.h | 1 +
>   2 files changed, 7 insertions(+)
>
> diff --git a/hw/misc/mchp_pfsoc_ioscb.c b/hw/misc/mchp_pfsoc_ioscb.c
> index f4fd55a0e5..f976e42f72 100644
> --- a/hw/misc/mchp_pfsoc_ioscb.c
> +++ b/hw/misc/mchp_pfsoc_ioscb.c
> @@ -33,6 +33,7 @@
>    */
>   #define IOSCB_WHOLE_REG_SIZE        0x10000000
>   #define IOSCB_SUBMOD_REG_SIZE       0x1000
> +#define IOSCB_CCC_REG_SIZE          0x2000000
>   
>   /*
>    * There are many sub-modules in the IOSCB module.
> @@ -45,6 +46,7 @@
>   #define IOSCB_LANE23_BASE           0x06510000
>   #define IOSCB_CTRL_BASE             0x07020000
>   #define IOSCB_CFG_BASE              0x07080000
> +#define IOSCB_CCC_BASE              0x08000000
>   #define IOSCB_PLL_MSS_BASE          0x0E001000
>   #define IOSCB_CFM_MSS_BASE          0x0E002000
>   #define IOSCB_PLL_DDR_BASE          0x0E010000
> @@ -168,6 +170,10 @@ static void mchp_pfsoc_ioscb_realize(DeviceState *dev, 
> Error **errp)
>                             "mchp.pfsoc.ioscb.cfg", IOSCB_SUBMOD_REG_SIZE);
>       memory_region_add_subregion(&s->container, IOSCB_CFG_BASE, &s->cfg);
>   
> +    memory_region_init_io(&s->ccc, OBJECT(s), &mchp_pfsoc_dummy_ops, s,
> +                          "mchp.pfsoc.ioscb.ccc", IOSCB_CCC_REG_SIZE);
> +    memory_region_add_subregion(&s->container, IOSCB_CCC_BASE, &s->ccc);

Unrelated but using the TYPE_UNIMPLEMENTED_DEVICE would ease tracing all
these block accesses, as the block name would appear before the 
address/size. See for example aspeed_mmio_map_unimplemented();

Otherwise LGTM.

Regards,

Phil.

>       memory_region_init_io(&s->pll_mss, OBJECT(s), &mchp_pfsoc_pll_ops, s,
>                             "mchp.pfsoc.ioscb.pll_mss", IOSCB_SUBMOD_REG_SIZE);
>       memory_region_add_subregion(&s->container, IOSCB_PLL_MSS_BASE, 
> &s->pll_mss);
> diff --git a/include/hw/misc/mchp_pfsoc_ioscb.h 
> b/include/hw/misc/mchp_pfsoc_ioscb.h
> index 9235523e33..687b213742 100644
> --- a/include/hw/misc/mchp_pfsoc_ioscb.h
> +++ b/include/hw/misc/mchp_pfsoc_ioscb.h
> @@ -30,6 +30,7 @@ typedef struct MchpPfSoCIoscbState {
>       MemoryRegion lane23;
>       MemoryRegion ctrl;
>       MemoryRegion cfg;
> +    MemoryRegion ccc;
>       MemoryRegion pll_mss;
>       MemoryRegion cfm_mss;
>       MemoryRegion pll_ddr;