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soc: ixp4xx-npe: Access syscon regs using regmap 

If we access the syscon (expansion bus config registers) using the
syscon regmap instead of relying on direct accessor functions,
we do not need to call this static code in the machine
(arch/arm/mach-ixp4xx/common.c) which makes things less dependent
on custom machine-dependent code.

Look up the syscon regmap and handle the error: this will make
deferred probe work with relation to the syscon.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220211223238.648934-8-linus.walleij@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Linus Walleij 2022-02-11 23:32:32 +01:00
parent b50113cbdd
commit 8754a7e61c
3 changed files with 27 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/soc/ixp4xx/Kconfig
View File

@ -12,6 +12,7 @@ config IXP4XX_QMGR
config IXP4XX_NPE
tristate "IXP4xx Network Processor Engine support"
select FW_LOADER
select MFD_SYSCON
help
This driver supports IXP4xx built-in network coprocessors
and is automatically selected by Ethernet and HSS drivers.

33
drivers/soc/ixp4xx/ixp4xx-npe.c
View File

@ -16,6 +16,7 @@
#include <linux/firmware.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
@ -284,6 +285,7 @@ static int __must_check npe_logical_reg_write32(struct npe *npe, u32 addr,
static int npe_reset(struct npe *npe)
{
u32 reset_bit = (IXP4XX_FEATURE_RESET_NPEA << npe->id);
u32 val, ctl, exec_count, ctx_reg2;
int i;
@ -380,16 +382,19 @@ static int npe_reset(struct npe *npe)
__raw_writel(0, &npe->regs->action_points[3]);
__raw_writel(0, &npe->regs->watch_count);
val = ixp4xx_read_feature_bits();
/*
* We need to work on cached values here because the register
* will read inverted but needs to be written non-inverted.
*/
val = cpu_ixp4xx_features(npe->rmap);
/* reset the NPE */
ixp4xx_write_feature_bits(val &
~(IXP4XX_FEATURE_RESET_NPEA << npe->id));
regmap_write(npe->rmap, IXP4XX_EXP_CNFG2, val & ~reset_bit);
/* deassert reset */
ixp4xx_write_feature_bits(val |
(IXP4XX_FEATURE_RESET_NPEA << npe->id));
regmap_write(npe->rmap, IXP4XX_EXP_CNFG2, val | reset_bit);
for (i = 0; i < MAX_RETRIES; i++) {
if (ixp4xx_read_feature_bits() &
(IXP4XX_FEATURE_RESET_NPEA << npe->id))
val = cpu_ixp4xx_features(npe->rmap);
if (val & reset_bit)
break; /* NPE is back alive */
udelay(1);
}
@ -683,6 +688,14 @@ static int ixp4xx_npe_probe(struct platform_device *pdev)
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct resource *res;
struct regmap *rmap;
u32 val;
/* This system has only one syscon, so fetch it */
rmap = syscon_regmap_lookup_by_compatible("syscon");
if (IS_ERR(rmap))
return dev_err_probe(dev, PTR_ERR(rmap),
"failed to look up syscon\n");
for (i = 0; i < NPE_COUNT; i++) {
struct npe *npe = &npe_tab[i];
@ -691,8 +704,9 @@ static int ixp4xx_npe_probe(struct platform_device *pdev)
if (!res)
return -ENODEV;
if (!(ixp4xx_read_feature_bits() &
(IXP4XX_FEATURE_RESET_NPEA << i))) {
val = cpu_ixp4xx_features(rmap);
if (!(val & (IXP4XX_FEATURE_RESET_NPEA << i))) {
dev_info(dev, "NPE%d at %pR not available\n",
i, res);
continue; /* NPE already disabled or not present */
@ -700,6 +714,7 @@ static int ixp4xx_npe_probe(struct platform_device *pdev)
npe->regs = devm_ioremap_resource(dev, res);
if (IS_ERR(npe->regs))
return PTR_ERR(npe->regs);
npe->rmap = rmap;
if (npe_reset(npe)) {
dev_info(dev, "NPE%d at %pR does not reset\n",

2
include/linux/soc/ixp4xx/npe.h
View File

@ -3,6 +3,7 @@
#define __IXP4XX_NPE_H
#include <linux/kernel.h>
#include <linux/regmap.h>
extern const char *npe_names[];
@ -17,6 +18,7 @@ struct npe_regs {
struct npe {
struct npe_regs __iomem *regs;
struct regmap *rmap;
int id;
int valid;
};