Re: [PATCH v4 11/17] media: rzg2l-cru: Add register mapping support

From: Laurent Pinchart
Date: Thu Mar 27 2025 - 13:08:02 EST

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On Thu, Mar 27, 2025 at 05:45:39PM +0100, Tommaso Merciai wrote:
> Hi Laurent,
>
> Thanks for your comment.
>
> On Thu, Mar 27, 2025 at 12:15:54PM +0200, Laurent Pinchart wrote:
> > Hi Tommaso,
> >
> > Thanks for being patient (and reminding me about this). Apparently,
> > Embedded World is bad for e-mail backlogs.
>
> I can imagine.
> I skipped the EW this year, hope you had fun there :)
> No worries.
>
> >
> > On Thu, Mar 13, 2025 at 01:01:24PM +0100, Tommaso Merciai wrote:
> > > On Wed, Mar 12, 2025 at 01:37:25PM +0000, Biju Das wrote:
> > > > On 03 March 2025 16:08, Tommaso Merciai wrote:
> > > > >
> > > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > > > >
> > > > > Prepare for adding support for RZ/G3E and RZ/V2HP SoCs, which have a CRU-IP that is mostly identical
> > > > > to RZ/G2L but with different register offsets and additional registers. Introduce a flexible register
> > > > > mapping mechanism to handle these variations.
> > > > >
> > > > > Define the `rzg2l_cru_info` structure to store register mappings and pass it as part of the OF match
> > > > > data. Update the read/write functions to check out-of-bound accesses and use indexed register offsets
> > > > > from `rzg2l_cru_info`, ensuring compatibility across different SoC variants.
> > > > >
> > > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > > > > Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@xxxxxxxxxxxxxx>
> > > > > ---
> > > > > Changes since v2:
> > > > > - Implemented new rzg2l_cru_write/read() that now are checking out-of-bound
> > > > > accesses as suggested by LPinchart.
> > > > > - Fixed AMnMBxADDRL() and AMnMBxADDRH() as suggested by LPinchart.
> > > > > - Update commit body
> > > > >
> > > > > .../platform/renesas/rzg2l-cru/rzg2l-core.c | 46 ++++++++++++-
> > > > > .../renesas/rzg2l-cru/rzg2l-cru-regs.h | 66 ++++++++++---------
> > > > > .../platform/renesas/rzg2l-cru/rzg2l-cru.h | 4 ++
> > > > > .../platform/renesas/rzg2l-cru/rzg2l-video.c | 58 ++++++++++++++--
> > > > > 4 files changed, 139 insertions(+), 35 deletions(-)
> > > > >
> > > > > diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-core.c
> > > > > b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-core.c
> > > > > index eed9d2bd0841..abc2a979833a 100644
> > > > > --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-core.c
> > > > > +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-core.c
> > > > > @@ -22,6 +22,7 @@
> > > > > #include <media/v4l2-mc.h>
> > > > >
> > > > > #include "rzg2l-cru.h"
> > > > > +#include "rzg2l-cru-regs.h"
> > > > >
> > > > > static inline struct rzg2l_cru_dev *notifier_to_cru(struct v4l2_async_notifier *n) { @@ -269,6
> > > > > +270,9 @@ static int rzg2l_cru_probe(struct platform_device *pdev)
> > > > >
> > > > > cru->dev = dev;
> > > > > cru->info = of_device_get_match_data(dev);
> > > > > + if (!cru->info)
> > > > > + return dev_err_probe(dev, -EINVAL,
> > > > > + "Failed to get OF match data\n");
> > > > >
> > > > > irq = platform_get_irq(pdev, 0);
> > > > > if (irq < 0)
> > > > > @@ -317,8 +321,48 @@ static void rzg2l_cru_remove(struct platform_device *pdev)
> > > > > rzg2l_cru_dma_unregister(cru);
> > > > > }
> > > > >
> > > > > +static const u16 rzg2l_cru_regs[] = {
> > > > > + [CRUnCTRL] = 0x0,
> > > > > + [CRUnIE] = 0x4,
> > > > > + [CRUnINTS] = 0x8,
> > > > > + [CRUnRST] = 0xc,
> > > > > + [AMnMB1ADDRL] = 0x100,
> > > > > + [AMnMB1ADDRH] = 0x104,
> > > > > + [AMnMB2ADDRL] = 0x108,
> > > > > + [AMnMB2ADDRH] = 0x10c,
> > > > > + [AMnMB3ADDRL] = 0x110,
> > > > > + [AMnMB3ADDRH] = 0x114,
> > > > > + [AMnMB4ADDRL] = 0x118,
> > > > > + [AMnMB4ADDRH] = 0x11c,
> > > > > + [AMnMB5ADDRL] = 0x120,
> > > > > + [AMnMB5ADDRH] = 0x124,
> > > > > + [AMnMB6ADDRL] = 0x128,
> > > > > + [AMnMB6ADDRH] = 0x12c,
> > > > > + [AMnMB7ADDRL] = 0x130,
> > > > > + [AMnMB7ADDRH] = 0x134,
> > > > > + [AMnMB8ADDRL] = 0x138,
> > > > > + [AMnMB8ADDRH] = 0x13c,
> > > > > + [AMnMBVALID] = 0x148,
> > > > > + [AMnMBS] = 0x14c,
> > > > > + [AMnAXIATTR] = 0x158,
> > > > > + [AMnFIFOPNTR] = 0x168,
> > > > > + [AMnAXISTP] = 0x174,
> > > > > + [AMnAXISTPACK] = 0x178,
> > > > > + [ICnEN] = 0x200,
> > > > > + [ICnMC] = 0x208,
> > > > > + [ICnMS] = 0x254,
> > > > > + [ICnDMR] = 0x26c,
> > > > > +};
> > > > > +
> > > > > +static const struct rzg2l_cru_info rzgl2_cru_info = {
> > > > > + .regs = rzg2l_cru_regs,
> > > > > +};
> > > > > +
> > > > > static const struct of_device_id rzg2l_cru_of_id_table[] = {
> > > > > - { .compatible = "renesas,rzg2l-cru", },
> > > > > + {
> > > > > + .compatible = "renesas,rzg2l-cru",
> > > > > + .data = &rzgl2_cru_info,
> > > > > + },
> > > > > { /* sentinel */ }
> > > > > };
> > > > > MODULE_DEVICE_TABLE(of, rzg2l_cru_of_id_table); diff --git a/drivers/media/platform/renesas/rzg2l-
> > > > > cru/rzg2l-cru-regs.h b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru-regs.h
> > > > > index 1c9f22118a5d..86c320286246 100644
> > > > > --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru-regs.h
> > > > > +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru-regs.h
> > > > > @@ -10,71 +10,77 @@
> > > > >
> > > > > /* HW CRU Registers Definition */
> > > > >
> > > > > -/* CRU Control Register */
> > > > > -#define CRUnCTRL 0x0
> > > > > #define CRUnCTRL_VINSEL(x) ((x) << 0)
> > > > >
> > > > > -/* CRU Interrupt Enable Register */
> > > > > -#define CRUnIE 0x4
> > > > > #define CRUnIE_EFE BIT(17)
> > > > >
> > > > > -/* CRU Interrupt Status Register */
> > > > > -#define CRUnINTS 0x8
> > > > > #define CRUnINTS_SFS BIT(16)
> > > > >
> > > > > -/* CRU Reset Register */
> > > > > -#define CRUnRST 0xc
> > > > > #define CRUnRST_VRESETN BIT(0)
> > > > >
> > > > > /* Memory Bank Base Address (Lower) Register for CRU Image Data */
> > > > > -#define AMnMBxADDRL(x) (0x100 + ((x) * 8))
> > > > > +#define AMnMBxADDRL(x) (AMnMB1ADDRL + (x) * 2)
> > > > >
> > > > > /* Memory Bank Base Address (Higher) Register for CRU Image Data */
> > > > > -#define AMnMBxADDRH(x) (0x104 + ((x) * 8))
> > > > > +#define AMnMBxADDRH(x) (AMnMB1ADDRH + (x) * 2)
> > > > >
> > > > > -/* Memory Bank Enable Register for CRU Image Data */
> > > > > -#define AMnMBVALID 0x148
> > > > > #define AMnMBVALID_MBVALID(x) GENMASK(x, 0)
> > > > >
> > > > > -/* Memory Bank Status Register for CRU Image Data */
> > > > > -#define AMnMBS 0x14c
> > > > > #define AMnMBS_MBSTS 0x7
> > > > >
> > > > > -/* AXI Master Transfer Setting Register for CRU Image Data */
> > > > > -#define AMnAXIATTR 0x158
> > > > > #define AMnAXIATTR_AXILEN_MASK GENMASK(3, 0)
> > > > > #define AMnAXIATTR_AXILEN (0xf)
> > > > >
> > > > > -/* AXI Master FIFO Pointer Register for CRU Image Data */
> > > > > -#define AMnFIFOPNTR 0x168
> > > > > #define AMnFIFOPNTR_FIFOWPNTR GENMASK(7, 0)
> > > > > #define AMnFIFOPNTR_FIFORPNTR_Y GENMASK(23, 16)
> > > > >
> > > > > -/* AXI Master Transfer Stop Register for CRU Image Data */
> > > > > -#define AMnAXISTP 0x174
> > > > > #define AMnAXISTP_AXI_STOP BIT(0)
> > > > >
> > > > > -/* AXI Master Transfer Stop Status Register for CRU Image Data */
> > > > > -#define AMnAXISTPACK 0x178
> > > > > #define AMnAXISTPACK_AXI_STOP_ACK BIT(0)
> > > > >
> > > > > -/* CRU Image Processing Enable Register */
> > > > > -#define ICnEN 0x200
> > > > > #define ICnEN_ICEN BIT(0)
> > > > >
> > > > > -/* CRU Image Processing Main Control Register */
> > > > > -#define ICnMC 0x208
> > > > > #define ICnMC_CSCTHR BIT(5)
> > > > > #define ICnMC_INF(x) ((x) << 16)
> > > > > #define ICnMC_VCSEL(x) ((x) << 22)
> > > > > #define ICnMC_INF_MASK GENMASK(21, 16)
> > > > >
> > > > > -/* CRU Module Status Register */
> > > > > -#define ICnMS 0x254
> > > > > #define ICnMS_IA BIT(2)
> > > > >
> > > > > -/* CRU Data Output Mode Register */
> > > > > -#define ICnDMR 0x26c
> > > > > #define ICnDMR_YCMODE_UYVY (1 << 4)
> > > > >
> > > > > +enum rzg2l_cru_common_regs {
> > > > > + CRUnCTRL, /* CRU Control */
> > > > > + CRUnIE, /* CRU Interrupt Enable */
> > > > > + CRUnINTS, /* CRU Interrupt Status */
> > > > > + CRUnRST, /* CRU Reset */
> > > > > + AMnMB1ADDRL, /* Bank 1 Address (Lower) for CRU Image Data */
> > > > > + AMnMB1ADDRH, /* Bank 1 Address (Higher) for CRU Image Data */
> > > > > + AMnMB2ADDRL, /* Bank 2 Address (Lower) for CRU Image Data */
> > > > > + AMnMB2ADDRH, /* Bank 2 Address (Higher) for CRU Image Data */
> > > > > + AMnMB3ADDRL, /* Bank 3 Address (Lower) for CRU Image Data */
> > > > > + AMnMB3ADDRH, /* Bank 3 Address (Higher) for CRU Image Data */
> > > > > + AMnMB4ADDRL, /* Bank 4 Address (Lower) for CRU Image Data */
> > > > > + AMnMB4ADDRH, /* Bank 4 Address (Higher) for CRU Image Data */
> > > > > + AMnMB5ADDRL, /* Bank 5 Address (Lower) for CRU Image Data */
> > > > > + AMnMB5ADDRH, /* Bank 5 Address (Higher) for CRU Image Data */
> > > > > + AMnMB6ADDRL, /* Bank 6 Address (Lower) for CRU Image Data */
> > > > > + AMnMB6ADDRH, /* Bank 6 Address (Higher) for CRU Image Data */
> > > > > + AMnMB7ADDRL, /* Bank 7 Address (Lower) for CRU Image Data */
> > > > > + AMnMB7ADDRH, /* Bank 7 Address (Higher) for CRU Image Data */
> > > > > + AMnMB8ADDRL, /* Bank 8 Address (Lower) for CRU Image Data */
> > > > > + AMnMB8ADDRH, /* Bank 8 Address (Higher) for CRU Image Data */
> > > > > + AMnMBVALID, /* Memory Bank Enable for CRU Image Data */
> > > > > + AMnMBS, /* Memory Bank Status for CRU Image Data */
> > > > > + AMnAXIATTR, /* AXI Master Transfer Setting Register for CRU Image Data */
> > > > > + AMnFIFOPNTR, /* AXI Master FIFO Pointer for CRU Image Data */
> > > > > + AMnAXISTP, /* AXI Master Transfer Stop for CRU Image Data */
> > > > > + AMnAXISTPACK, /* AXI Master Transfer Stop Status for CRU Image Data */
> > > > > + ICnEN, /* CRU Image Processing Enable */
> > > > > + ICnMC, /* CRU Image Processing Main Control */
> > > > > + ICnMS, /* CRU Module Status */
> > > > > + ICnDMR, /* CRU Data Output Mode */
> > > > > + RZG2L_CRU_MAX_REG,
> > > > > +};
> > > > > +
> > > > > #endif /* __RZG2L_CRU_REGS_H__ */
> > > > > diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
> > > > > b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
> > > > > index 8b898ce05b84..00c3f7458e20 100644
> > > > > --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
> > > > > +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
> > > > > @@ -80,6 +80,10 @@ struct rzg2l_cru_ip_format {
> > > > > bool yuv;
> > > > > };
> > > > >
> > > > > +struct rzg2l_cru_info {
> > > > > + const u16 *regs;
> > > > > +};
> > > > > +
> > > > > /**
> > > > > * struct rzg2l_cru_dev - Renesas CRU device structure
> > > > > * @dev: (OF) device
> > > > > diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> > > > > b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> > > > > index cd69c8a686d3..792f0df51a4b 100644
> > > > > --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> > > > > +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> > > > > @@ -42,16 +42,66 @@ struct rzg2l_cru_buffer {
> > > > > /* -----------------------------------------------------------------------------
> > > > > * DMA operations
> > > > > */
> > > > > -static void rzg2l_cru_write(struct rzg2l_cru_dev *cru, u32 offset, u32 value)
> > > > > +static void __rzg2l_cru_write(struct rzg2l_cru_dev *cru, u32 offset,
> > > > > +u32 value)
> > > > > {
> > > > > - iowrite32(value, cru->base + offset);
> > > > > + const u16 *regs = cru->info->regs;
> > > > > +
> > > > > + /*
> > > > > + * CRUnCTRL is a first register on all CRU supported SoCs so validate
> > > > > + * rest of the registers have valid offset being set in cru->info->regs.
> > > > > + */
> > > > > + if (WARN_ON(offset >= RZG2L_CRU_MAX_REG) ||
> > > > > + WARN_ON(offset != CRUnCTRL && regs[offset] == 0))
> > > > > + return;
> > > > > +
> > > > > + iowrite32(value, cru->base + regs[offset]); }
> > > > > +
> > > > > +static u32 __rzg2l_cru_read(struct rzg2l_cru_dev *cru, u32 offset) {
> > > > > + const u16 *regs = cru->info->regs;
> > > > > +
> > > > > + /*
> > > > > + * CRUnCTRL is a first register on all CRU supported SoCs so validate
> > > > > + * rest of the registers have valid offset being set in cru->info->regs.
> > > > > + */
> > > > > + if (WARN_ON(offset >= RZG2L_CRU_MAX_REG) ||
> > > > > + WARN_ON(offset != CRUnCTRL && regs[offset] == 0))
> > > > > + return 0;
> > > > > +
> > > > > + return ioread32(cru->base + regs[offset]);
> > > > > }
> > > > >
> > > > > -static u32 rzg2l_cru_read(struct rzg2l_cru_dev *cru, u32 offset)
> > > > > +static inline void
> > > > > +__rzg2l_cru_write_constant(struct rzg2l_cru_dev *cru, u32 offset, u32 value)
> > > > > {
> > > > > - return ioread32(cru->base + offset);
> > > > > + const u16 *regs = cru->info->regs;
> > > > > +
> > > > > + BUILD_BUG_ON(offset >= RZG2L_CRU_MAX_REG);
> > > > > +
> > > > > + iowrite32(value, cru->base + regs[offset]);
> > > >
> > > > Do you need this code as the purpose is to test compile time constant and
> > > > It won't execute at run time?
> >
> > Biju, I'm not sure to understan this comment.
> > __rzg2l_cru_write_constant() is called at runtime, with a compile-time
> > constant offset. The BUILD_BUG_ON() verifies at compile time that the
> > offset is valid, causing compilation errors if it isn't.
> >
> > __rzg2l_cru_write(), on the other hand, is called when the offset is not
> > known at compile time, because it's computed dynamically. That's a small
> > subset of the calls. It needs to check the offset at runtime for
> > overflows.
> >
> > What do you mean by "won't execute at runtime", and what code do you
> > think is not needed ?
> >
> > > It was suggested in a previous review.
> > >
> > > I've done some investigation on the above bot issue here.
> > > Using __always_inline for constant read/write issue seems solved.
> > >
> > > I found this link: https://www.kernel.org/doc/local/inline.html
> > >
> > > But tbh I'm not finding an example into the kernel that use both
> > > BUILD_BUG_ON and __always_inline.
> > >
> > > Laurent what do you think about? Do you have some hints?
> > > Thanks in advance.
> >
> > Do you mean that the compile-time assertions are caused by
> > __rzg2l_cru_write_constant() not being inlined ?
>
> Seems yes.
> Using __always_inline seems to solve the issue reported by the bot test.
>
> > The function could be
> > marked as __always_inline I suppose. Or the BUILD_BUG_ON() check could
> > be moved to the rzg2l_cru_write() macro.
>
> Mmm not sure that I completely got this way.
>
> Actually we have:
>
> #define rzg2l_cru_write(cru, offset, value) \
> (__builtin_constant_p(offset) ? \
> __rzg2l_cru_write_constant(cru, offset, value) : \
> __rzg2l_cru_write(cru, offset, value))
>
> And BUILD_BUG_ON() can only be user on constant offset.

There seems to be quite a few examples of usage of __always_inline with
BUILD_BUG_ON(), so we can go that way. Otherwise, you could write
something like (untested)

#define rzg2l_cru_write(cru, offset, value) \
({ \
u32 __offset = (offset); \
if (__builtin_constant_p(__offset)) { \
BUILD_BUG_ON(__offset >= RZG2L_CRU_MAX_REG); \
__rzg2l_cru_write_constant(cru, __offset, value); \
} else { \
__rzg2l_cru_write(cru, __offset, value)); \
} \
})

> > > > > }
> > > > >
> > > > > +static inline u32
> > > > > +__rzg2l_cru_read_constant(struct rzg2l_cru_dev *cru, u32 offset) {
> > > > > + const u16 *regs = cru->info->regs;
> > > > > +
> > > > > + BUILD_BUG_ON(offset >= RZG2L_CRU_MAX_REG);
> > > > > +
> > > > > + return ioread32(cru->base + regs[offset]);
> > > >
> > > > Do you need this code as the purpose is to test compile time constant and
> > > > It won't execute at run time?
> > > >
> > > > Not sure, maybe adding an entry with MAX_ID in LUT,
> > > > that will avoid buffer overflows and you can take out
> > > > All out of bound array checks?
> > > >
> > > > Cheers,
> > > > Biju
> > > >
> > > > }
> > > > > +
> > > > > +#define rzg2l_cru_write(cru, offset, value) \
> > > > > + (__builtin_constant_p(offset) ? \
> > > > > + __rzg2l_cru_write_constant(cru, offset, value) : \
> > > > > + __rzg2l_cru_write(cru, offset, value))
> > > > > +
> > > > > +#define rzg2l_cru_read(cru, offset) \
> > > > > + (__builtin_constant_p(offset) ? \
> > > > > + __rzg2l_cru_read_constant(cru, offset) : \
> > > > > + __rzg2l_cru_read(cru, offset))
> > > > > +
> > > > > /* Need to hold qlock before calling */ static void return_unused_buffers(struct rzg2l_cru_dev *cru,
> > > > > enum vb2_buffer_state state)

--
Regards,

Laurent Pinchart

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