2021-11-17 09:37:25

by Wolfram Sang

[permalink] [raw]
Subject: [PATCH] memory: renesas-rpc-if: avoid use of undocumented bits

Instead of writing fixed values with undocumented bits which happen to
be set on some SoCs, better switch to read-modify-write operations
changing only bits which are documented. This is way more future-proof
as we don't know yet how these bits may be on upcoming SoCs.

Signed-off-by: Wolfram Sang <[email protected]>
---

This patch is based on the Krzysztof's for-next branch as it depends on
Prabhakar's G2L additions.

Tested on a V3U with some debug code verifying that the same values are
written before and after the patch.

@Prabhakar: would you be so kind and test this patch on G2L?

drivers/memory/renesas-rpc-if.c | 58 +++++++++++++--------------------
1 file changed, 22 insertions(+), 36 deletions(-)

diff --git a/drivers/memory/renesas-rpc-if.c b/drivers/memory/renesas-rpc-if.c
index 8c51145c0f5c..a9f3e7bdddf8 100644
--- a/drivers/memory/renesas-rpc-if.c
+++ b/drivers/memory/renesas-rpc-if.c
@@ -20,7 +20,6 @@

#define RPCIF_CMNCR 0x0000 /* R/W */
#define RPCIF_CMNCR_MD BIT(31)
-#define RPCIF_CMNCR_SFDE BIT(24) /* undocumented but must be set */
#define RPCIF_CMNCR_MOIIO3(val) (((val) & 0x3) << 22)
#define RPCIF_CMNCR_MOIIO2(val) (((val) & 0x3) << 20)
#define RPCIF_CMNCR_MOIIO1(val) (((val) & 0x3) << 18)
@@ -290,49 +289,36 @@ int rpcif_hw_init(struct rpcif *rpc, bool hyperflash)
rpcif_rzg2l_timing_adjust_sdr(rpc);
}

- /*
- * NOTE: The 0x260 are undocumented bits, but they must be set.
- * RPCIF_PHYCNT_STRTIM is strobe timing adjustment bits,
- * 0x0 : the delay is biggest,
- * 0x1 : the delay is 2nd biggest,
- * On H3 ES1.x, the value should be 0, while on others,
- * the value should be 7.
- */
- if (rpc->type == RPCIF_RCAR_GEN3) {
- regmap_write(rpc->regmap, RPCIF_PHYCNT, RPCIF_PHYCNT_STRTIM(7) |
- RPCIF_PHYCNT_PHYMEM(hyperflash ? 3 : 0) | 0x260);
- } else {
- regmap_read(rpc->regmap, RPCIF_PHYCNT, &dummy);
- dummy &= ~RPCIF_PHYCNT_PHYMEM_MASK;
- dummy |= RPCIF_PHYCNT_PHYMEM(hyperflash ? 3 : 0) | 0x260;
- regmap_write(rpc->regmap, RPCIF_PHYCNT, dummy);
- }
+ regmap_update_bits(rpc->regmap, RPCIF_PHYCNT, RPCIF_PHYCNT_PHYMEM_MASK,
+ RPCIF_PHYCNT_PHYMEM(hyperflash ? 3 : 0));
+
+ if (rpc->type == RPCIF_RCAR_GEN3)
+ regmap_update_bits(rpc->regmap, RPCIF_PHYCNT,
+ RPCIF_PHYCNT_STRTIM(7), RPCIF_PHYCNT_STRTIM(7));

- /*
- * NOTE: The 0x1511144 are undocumented bits, but they must be set
- * for RPCIF_PHYOFFSET1.
- * The 0x31 are undocumented bits, but they must be set
- * for RPCIF_PHYOFFSET2.
- */
- regmap_write(rpc->regmap, RPCIF_PHYOFFSET1, 0x1511144 |
- RPCIF_PHYOFFSET1_DDRTMG(3));
- regmap_write(rpc->regmap, RPCIF_PHYOFFSET2, 0x31 |
- RPCIF_PHYOFFSET2_OCTTMG(4));
+ regmap_update_bits(rpc->regmap, RPCIF_PHYOFFSET1, RPCIF_PHYOFFSET1_DDRTMG(3),
+ RPCIF_PHYOFFSET1_DDRTMG(3));
+ regmap_update_bits(rpc->regmap, RPCIF_PHYOFFSET2, RPCIF_PHYOFFSET2_OCTTMG(7),
+ RPCIF_PHYOFFSET2_OCTTMG(4));

if (hyperflash)
regmap_update_bits(rpc->regmap, RPCIF_PHYINT,
RPCIF_PHYINT_WPVAL, 0);

if (rpc->type == RPCIF_RCAR_GEN3)
- regmap_write(rpc->regmap, RPCIF_CMNCR, RPCIF_CMNCR_SFDE |
- RPCIF_CMNCR_MOIIO_HIZ | RPCIF_CMNCR_IOFV_HIZ |
- RPCIF_CMNCR_BSZ(hyperflash ? 1 : 0));
+ regmap_update_bits(rpc->regmap, RPCIF_CMNCR,
+ RPCIF_CMNCR_MOIIO_HIZ | RPCIF_CMNCR_BSZ(3),
+ RPCIF_CMNCR_MOIIO_HIZ |
+ RPCIF_CMNCR_BSZ(hyperflash ? 1 : 0));
else
- regmap_write(rpc->regmap, RPCIF_CMNCR, RPCIF_CMNCR_SFDE |
- RPCIF_CMNCR_MOIIO3(1) | RPCIF_CMNCR_MOIIO2(1) |
- RPCIF_CMNCR_MOIIO1(1) | RPCIF_CMNCR_MOIIO0(1) |
- RPCIF_CMNCR_IO3FV(2) | RPCIF_CMNCR_IO2FV(2) |
- RPCIF_CMNCR_IO0FV(2) | RPCIF_CMNCR_BSZ(hyperflash ? 1 : 0));
+ regmap_update_bits(rpc->regmap, RPCIF_CMNCR,
+ RPCIF_CMNCR_MOIIO_HIZ | RPCIF_CMNCR_IOFV_HIZ |
+ RPCIF_CMNCR_BSZ(3),
+ RPCIF_CMNCR_MOIIO3(1) | RPCIF_CMNCR_MOIIO2(1) |
+ RPCIF_CMNCR_MOIIO1(1) | RPCIF_CMNCR_MOIIO0(1) |
+ RPCIF_CMNCR_IO3FV(2) | RPCIF_CMNCR_IO2FV(2) |
+ RPCIF_CMNCR_IO0FV(2) |
+ RPCIF_CMNCR_BSZ(hyperflash ? 1 : 0));

/* Set RCF after BSZ update */
regmap_write(rpc->regmap, RPCIF_DRCR, RPCIF_DRCR_RCF);
--
2.30.2



2021-11-18 02:54:18

by Prabhakar Mahadev Lad

[permalink] [raw]
Subject: RE: [PATCH] memory: renesas-rpc-if: avoid use of undocumented bits

Hi Wolfram,

Thank you for the patch.

> -----Original Message-----
> From: Wolfram Sang <[email protected]>
> Sent: 17 November 2021 09:37
> To: [email protected]
> Cc: Prabhakar Mahadev Lad <[email protected]>; Wolfram Sang <wsa+renesas@sang-
> engineering.com>; Krzysztof Kozlowski <[email protected]>; linux-
> [email protected]
> Subject: [PATCH] memory: renesas-rpc-if: avoid use of undocumented bits
>
> Instead of writing fixed values with undocumented bits which happen to be set on some SoCs, better
> switch to read-modify-write operations changing only bits which are documented. This is way more
> future-proof as we don't know yet how these bits may be on upcoming SoCs.
>
> Signed-off-by: Wolfram Sang <[email protected]>
> ---
>
> This patch is based on the Krzysztof's for-next branch as it depends on Prabhakar's G2L additions.
>
> Tested on a V3U with some debug code verifying that the same values are written before and after the
> patch.
>
> @Prabhakar: would you be so kind and test this patch on G2L?
>
Dumped the registers before and after patch, register values do match. Also tested read/write operation on RZ/G2L.

Tested-by: Lad Prabhakar <[email protected]>
Reviewed-by: Lad Prabhakar <[email protected]>

Cheers,
Prabhakar

> drivers/memory/renesas-rpc-if.c | 58 +++++++++++++--------------------
> 1 file changed, 22 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/memory/renesas-rpc-if.c b/drivers/memory/renesas-rpc-if.c index
> 8c51145c0f5c..a9f3e7bdddf8 100644
> --- a/drivers/memory/renesas-rpc-if.c
> +++ b/drivers/memory/renesas-rpc-if.c
> @@ -20,7 +20,6 @@
>
> #define RPCIF_CMNCR 0x0000 /* R/W */
> #define RPCIF_CMNCR_MD BIT(31)
> -#define RPCIF_CMNCR_SFDE BIT(24) /* undocumented but must be set */
> #define RPCIF_CMNCR_MOIIO3(val) (((val) & 0x3) << 22)
> #define RPCIF_CMNCR_MOIIO2(val) (((val) & 0x3) << 20)
> #define RPCIF_CMNCR_MOIIO1(val) (((val) & 0x3) << 18)
> @@ -290,49 +289,36 @@ int rpcif_hw_init(struct rpcif *rpc, bool hyperflash)
> rpcif_rzg2l_timing_adjust_sdr(rpc);
> }
>
> - /*
> - * NOTE: The 0x260 are undocumented bits, but they must be set.
> - * RPCIF_PHYCNT_STRTIM is strobe timing adjustment bits,
> - * 0x0 : the delay is biggest,
> - * 0x1 : the delay is 2nd biggest,
> - * On H3 ES1.x, the value should be 0, while on others,
> - * the value should be 7.
> - */
> - if (rpc->type == RPCIF_RCAR_GEN3) {
> - regmap_write(rpc->regmap, RPCIF_PHYCNT, RPCIF_PHYCNT_STRTIM(7) |
> - RPCIF_PHYCNT_PHYMEM(hyperflash ? 3 : 0) | 0x260);
> - } else {
> - regmap_read(rpc->regmap, RPCIF_PHYCNT, &dummy);
> - dummy &= ~RPCIF_PHYCNT_PHYMEM_MASK;
> - dummy |= RPCIF_PHYCNT_PHYMEM(hyperflash ? 3 : 0) | 0x260;
> - regmap_write(rpc->regmap, RPCIF_PHYCNT, dummy);
> - }
> + regmap_update_bits(rpc->regmap, RPCIF_PHYCNT, RPCIF_PHYCNT_PHYMEM_MASK,
> + RPCIF_PHYCNT_PHYMEM(hyperflash ? 3 : 0));
> +
> + if (rpc->type == RPCIF_RCAR_GEN3)
> + regmap_update_bits(rpc->regmap, RPCIF_PHYCNT,
> + RPCIF_PHYCNT_STRTIM(7), RPCIF_PHYCNT_STRTIM(7));
>
> - /*
> - * NOTE: The 0x1511144 are undocumented bits, but they must be set
> - * for RPCIF_PHYOFFSET1.
> - * The 0x31 are undocumented bits, but they must be set
> - * for RPCIF_PHYOFFSET2.
> - */
> - regmap_write(rpc->regmap, RPCIF_PHYOFFSET1, 0x1511144 |
> - RPCIF_PHYOFFSET1_DDRTMG(3));
> - regmap_write(rpc->regmap, RPCIF_PHYOFFSET2, 0x31 |
> - RPCIF_PHYOFFSET2_OCTTMG(4));
> + regmap_update_bits(rpc->regmap, RPCIF_PHYOFFSET1, RPCIF_PHYOFFSET1_DDRTMG(3),
> + RPCIF_PHYOFFSET1_DDRTMG(3));
> + regmap_update_bits(rpc->regmap, RPCIF_PHYOFFSET2, RPCIF_PHYOFFSET2_OCTTMG(7),
> + RPCIF_PHYOFFSET2_OCTTMG(4));
>
> if (hyperflash)
> regmap_update_bits(rpc->regmap, RPCIF_PHYINT,
> RPCIF_PHYINT_WPVAL, 0);
>
> if (rpc->type == RPCIF_RCAR_GEN3)
> - regmap_write(rpc->regmap, RPCIF_CMNCR, RPCIF_CMNCR_SFDE |
> - RPCIF_CMNCR_MOIIO_HIZ | RPCIF_CMNCR_IOFV_HIZ |
> - RPCIF_CMNCR_BSZ(hyperflash ? 1 : 0));
> + regmap_update_bits(rpc->regmap, RPCIF_CMNCR,
> + RPCIF_CMNCR_MOIIO_HIZ | RPCIF_CMNCR_BSZ(3),
> + RPCIF_CMNCR_MOIIO_HIZ |
> + RPCIF_CMNCR_BSZ(hyperflash ? 1 : 0));
> else
> - regmap_write(rpc->regmap, RPCIF_CMNCR, RPCIF_CMNCR_SFDE |
> - RPCIF_CMNCR_MOIIO3(1) | RPCIF_CMNCR_MOIIO2(1) |
> - RPCIF_CMNCR_MOIIO1(1) | RPCIF_CMNCR_MOIIO0(1) |
> - RPCIF_CMNCR_IO3FV(2) | RPCIF_CMNCR_IO2FV(2) |
> - RPCIF_CMNCR_IO0FV(2) | RPCIF_CMNCR_BSZ(hyperflash ? 1 : 0));
> + regmap_update_bits(rpc->regmap, RPCIF_CMNCR,
> + RPCIF_CMNCR_MOIIO_HIZ | RPCIF_CMNCR_IOFV_HIZ |
> + RPCIF_CMNCR_BSZ(3),
> + RPCIF_CMNCR_MOIIO3(1) | RPCIF_CMNCR_MOIIO2(1) |
> + RPCIF_CMNCR_MOIIO1(1) | RPCIF_CMNCR_MOIIO0(1) |
> + RPCIF_CMNCR_IO3FV(2) | RPCIF_CMNCR_IO2FV(2) |
> + RPCIF_CMNCR_IO0FV(2) |
> + RPCIF_CMNCR_BSZ(hyperflash ? 1 : 0));
>
> /* Set RCF after BSZ update */
> regmap_write(rpc->regmap, RPCIF_DRCR, RPCIF_DRCR_RCF);
> --
> 2.30.2


2021-11-18 13:07:07

by Wolfram Sang

[permalink] [raw]
Subject: Re: [PATCH] memory: renesas-rpc-if: avoid use of undocumented bits


> Dumped the registers before and after patch, register values do match. Also tested read/write operation on RZ/G2L.
>
> Tested-by: Lad Prabhakar <[email protected]>
> Reviewed-by: Lad Prabhakar <[email protected]>

Awesome, thanks for the lightning fast testing and review!


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2021-11-22 09:55:14

by Krzysztof Kozlowski

[permalink] [raw]
Subject: Re: [PATCH] memory: renesas-rpc-if: avoid use of undocumented bits

On Wed, 17 Nov 2021 10:37:10 +0100, Wolfram Sang wrote:
> Instead of writing fixed values with undocumented bits which happen to
> be set on some SoCs, better switch to read-modify-write operations
> changing only bits which are documented. This is way more future-proof
> as we don't know yet how these bits may be on upcoming SoCs.
>
>

Applied, thanks!

[1/1] memory: renesas-rpc-if: avoid use of undocumented bits
commit: 57ea9daad51f7707f61a602a743decf10cf9fea9

Best regards,
--
Krzysztof Kozlowski <[email protected]>