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Message-ID: <CACPK8Xc7y3GtcJCVYYs-JKTqBZvqVeZaz5MUk=UX151SX1xEFw@mail.gmail.com>
Date: Thu, 29 Sep 2016 16:15:13 +0930
From: Joel Stanley <joel@....id.au>
To: Andrew Jeffery <andrew@...id.au>,
Linus Walleij <linus.walleij@...aro.org>
Cc: Mark Rutland <mark.rutland@....com>,
Rob Herring <robh+dt@...nel.org>, linux-gpio@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org,
OpenBMC Maillist <openbmc@...ts.ozlabs.org>
Subject: Re: [PATCH 5/8] pinctrl: aspeed: Enable capture of off-SCU pinmux state
On Wed, Sep 28, 2016 at 12:20 AM, Andrew Jeffery <andrew@...id.au> wrote:
> The System Control Unit IP in the Aspeed SoCs is typically where the
> pinmux configuration is found.
>
> But not always.
>
> On the AST2400 and AST2500 a number of pins depend on state in one of
> the SIO, LPC or GFX IP blocks, so add support to at least capture what
> that state is. The pinctrl engine for the Aspeed SoCs doesn't try to
> inspect or modify the state of the off-SCU IP blocks. Instead, it logs
> the state requirement with the expectation that the platform
> designer/maintainer arranges for the appropriate configuration to be
> applied through the associated drivers.
This is unfortunate.
This patch kicks the can down the road, but doesn't solve the problem
for a user who wants to configure some functionality that depends on
the non-SCU bits. Because of this I'm not sure if we want to put it in
the tree.
However, I'm not sure what a proper solution would look like. Perhaps
Linus can point out another SoC that has a similar problem?
Cheers,
Joel
>
> The IP block of interest is encoded in the reg member of struct
> aspeed_sig_desc. For compatibility with the existing code, the SCU is
> defined to have an IP value of 0.
>
> Signed-off-by: Andrew Jeffery <andrew@...id.au>
> ---
> drivers/pinctrl/aspeed/pinctrl-aspeed.c | 53 +++++++++++++++++++++++---
> drivers/pinctrl/aspeed/pinctrl-aspeed.h | 16 +++++++-
> 2 files changed, 61 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/pinctrl/aspeed/pinctrl-aspeed.c b/drivers/pinctrl/aspeed/pinctrl-aspeed.c
> index 49aeba912531..21ef195d586f 100644
> --- a/drivers/pinctrl/aspeed/pinctrl-aspeed.c
> +++ b/drivers/pinctrl/aspeed/pinctrl-aspeed.c
> @@ -14,6 +14,8 @@
> #include "../core.h"
> #include "pinctrl-aspeed.h"
>
> +const char *const aspeed_pinmux_ips[] = { "SCU", "SIO", "GFX", "LPC" };
> +
> int aspeed_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
> {
> struct aspeed_pinctrl_data *pdata = pinctrl_dev_get_drvdata(pctldev);
> @@ -78,7 +80,9 @@ int aspeed_pinmux_get_fn_groups(struct pinctrl_dev *pctldev,
> static inline void aspeed_sig_desc_print_val(
> const struct aspeed_sig_desc *desc, bool enable, u32 rv)
> {
> - pr_debug("SCU%x[0x%08x]=0x%x, got 0x%x from 0x%08x\n", desc->reg,
> + pr_debug("Want %s%lX[0x%08X]=0x%X, got 0x%X from 0x%08X\n",
> + aspeed_pinmux_ips[SIG_DESC_IP_FROM_REG(desc->reg)],
> + SIG_DESC_OFFSET_FROM_REG(desc->reg),
> desc->mask, enable ? desc->enable : desc->disable,
> (rv & desc->mask) >> __ffs(desc->mask), rv);
> }
> @@ -105,6 +109,8 @@ static bool aspeed_sig_desc_eval(const struct aspeed_sig_desc *desc,
> unsigned int raw;
> u32 want;
>
> + WARN_ON(SIG_DESC_IP_FROM_REG(desc->reg) != ASPEED_IP_SCU);
> +
> if (regmap_read(map, desc->reg, &raw) < 0)
> return false;
>
> @@ -142,9 +148,19 @@ static bool aspeed_sig_expr_eval(const struct aspeed_sig_expr *expr,
>
> for (i = 0; i < expr->ndescs; i++) {
> const struct aspeed_sig_desc *desc = &expr->descs[i];
> + size_t ip = SIG_DESC_IP_FROM_REG(desc->reg);
> +
> + if (ip == ASPEED_IP_SCU) {
> + if (!aspeed_sig_desc_eval(desc, enabled, map))
> + return false;
> + } else {
> + size_t offset = SIG_DESC_OFFSET_FROM_REG(desc->reg);
> + const char *ip_name = aspeed_pinmux_ips[ip];
> +
> + pr_debug("Ignoring configuration of field %s%X[0x%08X]\n",
> + ip_name, offset, desc->mask);
> + }
>
> - if (!aspeed_sig_desc_eval(desc, enabled, map))
> - return false;
> }
>
> return true;
> @@ -170,7 +186,14 @@ static bool aspeed_sig_expr_set(const struct aspeed_sig_expr *expr,
> for (i = 0; i < expr->ndescs; i++) {
> bool ret;
> const struct aspeed_sig_desc *desc = &expr->descs[i];
> +
> + size_t offset = SIG_DESC_OFFSET_FROM_REG(desc->reg);
> + size_t ip = SIG_DESC_IP_FROM_REG(desc->reg);
> + bool is_scu = (ip == ASPEED_IP_SCU);
> + const char *ip_name = aspeed_pinmux_ips[ip];
> +
> u32 pattern = enable ? desc->enable : desc->disable;
> + u32 val = (pattern << __ffs(desc->mask));
>
> /*
> * Strap registers are configured in hardware or by early-boot
> @@ -179,11 +202,27 @@ static bool aspeed_sig_expr_set(const struct aspeed_sig_expr *expr,
> * deconfigured and is the reason we re-evaluate after writing
> * all descriptor bits.
> */
> - if (desc->reg == HW_STRAP1 || desc->reg == HW_STRAP2)
> + if (is_scu && (offset == HW_STRAP1 || offset == HW_STRAP2))
> continue;
>
> - ret = regmap_update_bits(map, desc->reg, desc->mask,
> - pattern << __ffs(desc->mask)) == 0;
> + /*
> + * Sometimes we need help from IP outside the SCU to activate a
> + * mux request. Report that we need its cooperation.
> + */
> + if (enable && !is_scu) {
> + pr_debug("Pinmux request for %s requires cooperation of %s IP: Need (%s%X[0x%08X] = 0x%08X\n",
> + expr->function, ip_name, ip_name, offset,
> + desc->mask, val);
> + }
> +
> + /* And only read/write SCU registers */
> + if (!is_scu) {
> + pr_debug("Skipping configuration of field %s%X[0x%08X]\n",
> + ip_name, offset, desc->mask);
> + continue;
> + }
> +
> + ret = regmap_update_bits(map, desc->reg, desc->mask, val) == 0;
>
> if (!ret)
> return ret;
> @@ -343,6 +382,8 @@ int aspeed_pinmux_set_mux(struct pinctrl_dev *pctldev, unsigned int function,
> const struct aspeed_sig_expr **funcs;
> const struct aspeed_sig_expr ***prios;
>
> + pr_debug("Muxing pin %d for %s\n", pin, pfunc->name);
> +
> if (!pdesc)
> return -EINVAL;
>
> diff --git a/drivers/pinctrl/aspeed/pinctrl-aspeed.h b/drivers/pinctrl/aspeed/pinctrl-aspeed.h
> index 3e72ef8c54bf..4384407d77fb 100644
> --- a/drivers/pinctrl/aspeed/pinctrl-aspeed.h
> +++ b/drivers/pinctrl/aspeed/pinctrl-aspeed.h
> @@ -232,6 +232,15 @@
> * group.
> */
>
> +#define ASPEED_IP_SCU 0
> +#define ASPEED_IP_SIO 1
> +#define ASPEED_IP_GFX 2
> +#define ASPEED_IP_LPC 3
> +
> +#define SIG_DESC_TO_REG(ip, offset) (((ip) << 24) | (offset))
> +#define SIG_DESC_IP_FROM_REG(reg) (((reg) >> 24) & GENMASK(7, 0))
> +#define SIG_DESC_OFFSET_FROM_REG(reg) ((reg) & GENMASK(11, 0))
> +
> /*
> * The "Multi-function Pins Mapping and Control" table in the SoC datasheet
> * references registers by the device/offset mnemonic. The register macros
> @@ -261,7 +270,10 @@
> * A signal descriptor, which describes the register, bits and the
> * enable/disable values that should be compared or written.
> *
> - * @reg: The register offset from base in bytes
> + * @reg: Split into three fields:
> + * 31:24: IP selector
> + * 23:12: Reserved
> + * 11:0: Register offset
> * @mask: The mask to apply to the register. The lowest set bit of the mask is
> * used to derive the shift value.
> * @enable: The value that enables the function. Value should be in the LSBs,
> @@ -270,7 +282,7 @@
> * LSBs, not at the position of the mask.
> */
> struct aspeed_sig_desc {
> - unsigned int reg;
> + u32 reg;
> u32 mask;
> u32 enable;
> u32 disable;
> --
> git-series 0.8.10
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