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Message-ID: <6bc91742-66d8-425b-ba40-fe5fa6ba18c4@linaro.org>
Date: Tue, 13 Feb 2024 08:46:46 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Christophe Kerello <christophe.kerello@...s.st.com>,
miquel.raynal@...tlin.com, richard@....at, vigneshr@...com,
robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org
Cc: linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-stm32@...md-mailman.stormreply.com, devicetree@...r.kernel.org
Subject: Re: [PATCH 05/12] memory: stm32-fmc2-ebi: update the driver to
support revision 2
On 12/02/2024 18:48, Christophe Kerello wrote:
> Add the support of the revision 2 of FMC2 IP.
> - PCSCNTR register has been removed,
> - CFGR register has been added,
> - the bit used to enable the IP has moved from BCR1 to CFGR,
> - the timeout for CEx deassertion has moved from PCSCNTR to BCRx,
> - the continuous clock enable has moved from BCR1 to CFGR,
> - the clk divide ratio has moved from BCR1 to CFGR.
>
> Signed-off-by: Christophe Kerello <christophe.kerello@...s.st.com>
> ---
> drivers/memory/stm32-fmc2-ebi.c | 206 +++++++++++++++++++++++++-------
> 1 file changed, 163 insertions(+), 43 deletions(-)
>
> diff --git a/drivers/memory/stm32-fmc2-ebi.c b/drivers/memory/stm32-fmc2-ebi.c
> index d79dcb6c239a..066722274a45 100644
> --- a/drivers/memory/stm32-fmc2-ebi.c
> +++ b/drivers/memory/stm32-fmc2-ebi.c
> @@ -20,8 +20,10 @@
> #define FMC2_BCR(x) ((x) * 0x8 + FMC2_BCR1)
> #define FMC2_BTR(x) ((x) * 0x8 + FMC2_BTR1)
> #define FMC2_PCSCNTR 0x20
> +#define FMC2_CFGR 0x20
> #define FMC2_BWTR1 0x104
> #define FMC2_BWTR(x) ((x) * 0x8 + FMC2_BWTR1)
> +#define FMC2_VERR 0x3f4
>
> /* Register: FMC2_BCR1 */
> #define FMC2_BCR1_CCLKEN BIT(20)
> @@ -42,6 +44,7 @@
> #define FMC2_BCR_ASYNCWAIT BIT(15)
> #define FMC2_BCR_CPSIZE GENMASK(18, 16)
> #define FMC2_BCR_CBURSTRW BIT(19)
> +#define FMC2_BCR_CSCOUNT GENMASK(21, 20)
> #define FMC2_BCR_NBLSET GENMASK(23, 22)
>
> /* Register: FMC2_BTRx/FMC2_BWTRx */
> @@ -58,6 +61,15 @@
> #define FMC2_PCSCNTR_CSCOUNT GENMASK(15, 0)
> #define FMC2_PCSCNTR_CNTBEN(x) BIT((x) + 16)
>
> +/* Register: FMC2_CFGR */
> +#define FMC2_CFGR_CLKDIV GENMASK(19, 16)
> +#define FMC2_CFGR_CCLKEN BIT(20)
> +#define FMC2_CFGR_FMC2EN BIT(31)
> +
> +/* Register: FMC2_VERR */
> +#define FMC2_VERR_MAJREV GENMASK(7, 4)
> +#define FMC2_VERR_MAJREV_2 2
> +
> #define FMC2_MAX_EBI_CE 4
> #define FMC2_MAX_BANKS 5
>
> @@ -74,6 +86,11 @@
> #define FMC2_BCR_MTYP_PSRAM 0x1
> #define FMC2_BCR_MTYP_NOR 0x2
>
> +#define FMC2_BCR_CSCOUNT_0 0x0
> +#define FMC2_BCR_CSCOUNT_1 0x1
> +#define FMC2_BCR_CSCOUNT_64 0x2
> +#define FMC2_BCR_CSCOUNT_256 0x3
> +
> #define FMC2_BXTR_EXTMOD_A 0x0
> #define FMC2_BXTR_EXTMOD_B 0x1
> #define FMC2_BXTR_EXTMOD_C 0x2
> @@ -85,7 +102,7 @@
> #define FMC2_BXTR_DATAST_MAX 0xff
> #define FMC2_BXTR_BUSTURN_MAX 0xf
> #define FMC2_BXTR_DATAHLD_MAX 0x3
> -#define FMC2_BTR_CLKDIV_MAX 0xf
> +#define FMC2_REG_CLKDIV_MAX 0xf
Why?
> #define FMC2_BTR_DATLAT_MAX 0xf
> #define FMC2_PCSCNTR_CSCOUNT_MAX 0xff
>
> @@ -101,7 +118,8 @@ enum stm32_fmc2_ebi_register_type {
> FMC2_REG_BCR = 1,
> FMC2_REG_BTR,
> FMC2_REG_BWTR,
> - FMC2_REG_PCSCNTR
> + FMC2_REG_PCSCNTR,
> + FMC2_REG_CFGR,
> };
>
> enum stm32_fmc2_ebi_transaction_type {
> @@ -132,6 +150,13 @@ enum stm32_fmc2_ebi_cpsize {
> FMC2_CPSIZE_1024 = 1024
> };
>
> +enum stm32_fmc2_ebi_cscount {
> + FMC2_CSCOUNT_0 = 0,
> + FMC2_CSCOUNT_1 = 1,
> + FMC2_CSCOUNT_64 = 64,
> + FMC2_CSCOUNT_256 = 256
> +};
> +
> struct stm32_fmc2_ebi_data {
> bool rnb_for_nand;
> };
> @@ -142,11 +167,13 @@ struct stm32_fmc2_ebi {
> struct regmap *regmap;
> const struct stm32_fmc2_ebi_data *data;
> u8 bank_assigned;
> + u8 majrev;
>
> u32 bcr[FMC2_MAX_EBI_CE];
> u32 btr[FMC2_MAX_EBI_CE];
> u32 bwtr[FMC2_MAX_EBI_CE];
> u32 pcscntr;
> + u32 cfgr;
> };
>
> /*
> @@ -274,15 +301,29 @@ static int stm32_fmc2_ebi_check_clk_period(struct stm32_fmc2_ebi *ebi,
> const struct stm32_fmc2_prop *prop,
> int cs)
> {
> - u32 bcr, bcr1;
> + u32 bcr, cfgr;
>
> regmap_read(ebi->regmap, FMC2_BCR(cs), &bcr);
> - if (cs)
> - regmap_read(ebi->regmap, FMC2_BCR1, &bcr1);
> - else
> - bcr1 = bcr;
>
> - if (bcr & FMC2_BCR_BURSTEN && (!cs || !(bcr1 & FMC2_BCR1_CCLKEN)))
> + if (ebi->majrev < FMC2_VERR_MAJREV_2) {
> + u32 bcr1;
> +
> + if (cs)
> + regmap_read(ebi->regmap, FMC2_BCR1, &bcr1);
> + else
> + bcr1 = bcr;
> +
> + if (bcr & FMC2_BCR_BURSTEN &&
> + (!cs || !(bcr1 & FMC2_BCR1_CCLKEN)))
> + return 0;
> +
> + return -EINVAL;
> + }
The function is not really readable anymore. Please split it into three
functions: for v1 (so original code), v2 and wrapper choosing it based
on revision). Or two functions and some sort of ops with function
pointers (so you call ops->check_clk_period). Or just parametrize the
registers with two different "struct reg_field" and use appropriate one
for given revision (the code looks the same!)
Or just two set of stm32_fmc2_child_props...
Anyway the duplicated code just two read different register is it not
the way to go.
> +
> + regmap_read(ebi->regmap, FMC2_CFGR, &cfgr);
> +
> + if (bcr & FMC2_BCR_BURSTEN &&
> + (!cs || !(cfgr & FMC2_CFGR_CCLKEN)))
> return 0;
>
> return -EINVAL;
> @@ -311,15 +352,29 @@ static u32 stm32_fmc2_ebi_ns_to_clk_period(struct stm32_fmc2_ebi *ebi,
> int cs, u32 setup)
> {
> u32 nb_clk_cycles = stm32_fmc2_ebi_ns_to_clock_cycles(ebi, cs, setup);
> - u32 bcr, btr, clk_period;
> + u32 btr, clk_period;
>
> - regmap_read(ebi->regmap, FMC2_BCR1, &bcr);
> - if (bcr & FMC2_BCR1_CCLKEN || !cs)
> - regmap_read(ebi->regmap, FMC2_BTR1, &btr);
> - else
> - regmap_read(ebi->regmap, FMC2_BTR(cs), &btr);
> + if (ebi->majrev < FMC2_VERR_MAJREV_2) {
> + u32 bcr;
>
> - clk_period = FIELD_GET(FMC2_BTR_CLKDIV, btr) + 1;
> + regmap_read(ebi->regmap, FMC2_BCR1, &bcr);
> + if (bcr & FMC2_BCR1_CCLKEN || !cs)
> + regmap_read(ebi->regmap, FMC2_BTR1, &btr);
> + else
> + regmap_read(ebi->regmap, FMC2_BTR(cs), &btr);
> +
> + clk_period = FIELD_GET(FMC2_BTR_CLKDIV, btr) + 1;
> + } else {
> + u32 cfgr;
> +
> + regmap_read(ebi->regmap, FMC2_CFGR, &cfgr);
> + if (cfgr & FMC2_CFGR_CCLKEN) {
> + clk_period = FIELD_GET(FMC2_CFGR_CLKDIV, cfgr) + 1;
> + } else {
> + regmap_read(ebi->regmap, FMC2_BTR(cs), &btr);
> + clk_period = FIELD_GET(FMC2_BTR_CLKDIV, btr) + 1;
> + }
> + }
>
> return DIV_ROUND_UP(nb_clk_cycles, clk_period);
> }
> @@ -339,6 +394,9 @@ static int stm32_fmc2_ebi_get_reg(int reg_type, int cs, u32 *reg)
> case FMC2_REG_PCSCNTR:
> *reg = FMC2_PCSCNTR;
> break;
> + case FMC2_REG_CFGR:
> + *reg = FMC2_CFGR;
> + break;
> default:
> return -EINVAL;
> }
> @@ -672,10 +730,26 @@ static int stm32_fmc2_ebi_set_clk_period(struct stm32_fmc2_ebi *ebi,
> int cs, u32 setup)
> {
> u32 val;
> + u32 reg = FMC2_BTR(cs);
> + u32 mask = FMC2_BTR_CLKDIV;
>
> - val = setup ? clamp_val(setup - 1, 1, FMC2_BTR_CLKDIV_MAX) : 1;
> - val = FIELD_PREP(FMC2_BTR_CLKDIV, val);
> - regmap_update_bits(ebi->regmap, FMC2_BTR(cs), FMC2_BTR_CLKDIV, val);
> + if (ebi->majrev >= FMC2_VERR_MAJREV_2) {
> + u32 cfgr;
> +
> + regmap_read(ebi->regmap, FMC2_CFGR, &cfgr);
> +
> + if (cfgr & FMC2_CFGR_CCLKEN) {
> + reg = FMC2_CFGR;
> + mask = FMC2_CFGR_CLKDIV;
> + }
> + }
> +
> + val = setup ? clamp_val(setup - 1, 1, FMC2_REG_CLKDIV_MAX) : 1;
> + if (reg == FMC2_CFGR)
> + val = FIELD_PREP(FMC2_CFGR_CLKDIV, val);
> + else
> + val = FIELD_PREP(FMC2_BTR_CLKDIV, val);
This scales poorly for any new revision. You should really start using
reg_field per each version.
> + regmap_update_bits(ebi->regmap, reg, mask, val);
>
> return 0;
> }
> @@ -697,27 +771,58 @@ static int stm32_fmc2_ebi_set_max_low_pulse(struct stm32_fmc2_ebi *ebi,
> const struct stm32_fmc2_prop *prop,
> int cs, u32 setup)
> {
> - u32 old_val, new_val, pcscntr;
> + u32 val;
> + u32 reg = ebi->majrev < FMC2_VERR_MAJREV_2 ? FMC2_PCSCNTR :
> + FMC2_BCR(cs);
> + u32 mask = ebi->majrev < FMC2_VERR_MAJREV_2 ? FMC2_PCSCNTR_CSCOUNT :
> + FMC2_BCR_CSCOUNT;
You have such code everywhere... sorry, that's not readable at all. No
conditional assignmnents, that's a clear NAK.
Best regards,
Krzysztof
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