Re: [PATCH] spi: spi-nxp-fspi: don't depend on a specific node name erratum workaround
From: Michael Walle
Date: Sat Oct 02 2021 - 04:59:50 EST
Am 2021-10-02 03:37, schrieb Vladimir Oltean:
On Fri, Oct 01, 2021 at 11:27:26PM +0200, Michael Walle wrote:
Make the workaround more reliable and just drop the unneeded sysclk
lookup.
For reference, the error during the bootup is the following:
[ 4.898400] nxp-fspi 20c0000.spi: Errata cannot be executed. Read
via IP bus may not work
Well, in Kuldeep's defence, at least this part is sane, right? I mean
we
cannot prove an issue => we don't disable reads via the AHB. So it's
just the error message (which I didn't notice TBH, sorry).
Its just an error message in case the platform clock is 400Mhz. But
if you have a 300MHz platform clock the workaround wouldn't be applied.
The reference is just there if someone stumbles over this error and
searches for it on google.
On the other hand, is anyone using LS1028A with a platform clock of 300
MHz? :)
Fixes: 82ce7d0e74b6 ("spi: spi-nxp-fspi: Implement errata workaround
for LS1028A")
Cc: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Signed-off-by: Michael Walle <michael@xxxxxxxx>
---
drivers/spi/spi-nxp-fspi.c | 26 +++++++-------------------
1 file changed, 7 insertions(+), 19 deletions(-)
diff --git a/drivers/spi/spi-nxp-fspi.c b/drivers/spi/spi-nxp-fspi.c
index a66fa97046ee..2b0301fc971c 100644
--- a/drivers/spi/spi-nxp-fspi.c
+++ b/drivers/spi/spi-nxp-fspi.c
@@ -33,6 +33,7 @@
#include <linux/acpi.h>
#include <linux/bitops.h>
+#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
@@ -315,6 +316,7 @@
#define NXP_FSPI_MIN_IOMAP SZ_4M
#define DCFG_RCWSR1 0x100
+#define SYS_PLL_RAT GENMASK(6, 2)
Ugh. So your solution still makes a raw read of the platform PLL value
from the DCFG, now it just adds a nice definition for it. Not nice.
Keep in mind that this is intended to be a fixes commit. I agree with
you that having a new clock in the device tree and checking that would
have been better. Feel free to change the workaround after this fix
is applied (without a fixes tag), but I don't think introducing a new
clock (and you forgot to update the bindings) will qualify as a fixes
commit. Esp. when you change the compatible string.
/* Access flash memory using IP bus only */
#define FSPI_QUIRK_USE_IP_ONLY BIT(0)
@@ -926,9 +928,8 @@ static void erratum_err050568(struct nxp_fspi *f)
{ .family = "QorIQ LS1028A" },
{ /* sentinel */ }
};
- struct device_node *np;
struct regmap *map;
- u32 val = 0, sysclk = 0;
+ u32 val, sys_pll_ratio;
int ret;
/* Check for LS1028A family */
@@ -937,7 +938,6 @@ static void erratum_err050568(struct nxp_fspi *f)
return;
}
- /* Compute system clock frequency multiplier ratio */
map = syscon_regmap_lookup_by_compatible("fsl,ls1028a-dcfg");
if (IS_ERR(map)) {
dev_err(f->dev, "No syscon regmap\n");
@@ -948,23 +948,11 @@ static void erratum_err050568(struct nxp_fspi
*f)
if (ret < 0)
goto err;
- /* Strap bits 6:2 define SYS_PLL_RAT i.e frequency multiplier ratio
*/
- val = (val >> 2) & 0x1F;
- WARN(val == 0, "Strapping is zero: Cannot determine ratio");
+ sys_pll_ratio = FIELD_GET(SYS_PLL_RAT, val);
+ dev_dbg(f->dev, "val: 0x%08x, sys_pll_ratio: %d\n", val,
sys_pll_ratio);
Do we really feel that this dev_dbg is valuable?
No, I just briefly looked at it to see it prints 4 ;)
- /* Compute system clock frequency */
- np = of_find_node_by_name(NULL, "clock-sysclk");
- if (!np)
- goto err;
-
- if (of_property_read_u32(np, "clock-frequency", &sysclk))
- goto err;
-
- sysclk = (sysclk * val) / 1000000; /* Convert sysclk to Mhz */
- dev_dbg(f->dev, "val: 0x%08x, sysclk: %dMhz\n", val, sysclk);
-
- /* Use IP bus only if PLL is 300MHz */
- if (sysclk == 300)
+ /* Use IP bus only if platform clock is 300MHz */
+ if (sys_pll_ratio == 3)
f->devtype_data->quirks |= FSPI_QUIRK_USE_IP_ONLY;
return;
--
2.30.2
How about:
diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
index 343ecf0e8973..ffe820c22719 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
+++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
@@ -326,15 +326,17 @@ i2c7: i2c@2070000 {
};
fspi: spi@20c0000 {
- compatible = "nxp,lx2160a-fspi";
+ compatible = "nxp,ls1028a-fspi";
Why not
compatible = "nxp,ls1028a-fspi", "nxp,lx2160a-fspi";
to keep at least some compatibility.
#address-cells = <1>;
#size-cells = <0>;
reg = <0x0 0x20c0000 0x0 0x10000>,
<0x0 0x20000000 0x0 0x10000000>;
reg-names = "fspi_base", "fspi_mmap";
interrupts = <GIC_SPI 25 IRQ_TYPE_LEVEL_HIGH>;
- clocks = <&fspi_clk>, <&fspi_clk>;
- clock-names = "fspi_en", "fspi";
+ clocks = <&fspi_clk>, <&fspi_clk>,
+ <&clockgen QORIQ_CLK_PLATFORM_PLL
+ QORIQ_CLK_PLL_DIV(2)>;
+ clock-names = "fspi_en", "fspi", "base";
status = "disabled";
};
diff --git a/drivers/spi/spi-nxp-fspi.c b/drivers/spi/spi-nxp-fspi.c
index a66fa97046ee..f2815e6cae2c 100644
--- a/drivers/spi/spi-nxp-fspi.c
+++ b/drivers/spi/spi-nxp-fspi.c
@@ -314,8 +314,6 @@
#define NXP_FSPI_MAX_CHIPSELECT 4
#define NXP_FSPI_MIN_IOMAP SZ_4M
-#define DCFG_RCWSR1 0x100
-
/* Access flash memory using IP bus only */
#define FSPI_QUIRK_USE_IP_ONLY BIT(0)
@@ -922,55 +920,18 @@ static int nxp_fspi_adjust_op_size(struct
spi_mem *mem, struct spi_mem_op *op)
static void erratum_err050568(struct nxp_fspi *f)
{
- const struct soc_device_attribute ls1028a_soc_attr[] = {
- { .family = "QorIQ LS1028A" },
- { /* sentinel */ }
- };
Mh, I see how you came to the conclusion to rename the compatible
string. But normally, this also contains a revision check,
which is missing here IMHO. It might as well be fixed in the
next revision (though we both know, this is highly unlikely; its
still wrong). So while you could rename the compatible (oh no!)
you'd still have to do the rev 1.0 check here.
- struct device_node *np;
- struct regmap *map;
- u32 val = 0, sysclk = 0;
- int ret;
+ struct clk *clk_base;
- /* Check for LS1028A family */
- if (!soc_device_match(ls1028a_soc_attr)) {
- dev_dbg(f->dev, "Errata applicable only for LS1028A\n");
+ clk_base = clk_get(f->dev, "base");
+ if (IS_ERR(clk_base)) {
+ dev_err(f->dev, "Errata cannot be executed. Read via IP bus may not
work\n");
return;
}
- /* Compute system clock frequency multiplier ratio */
- map = syscon_regmap_lookup_by_compatible("fsl,ls1028a-dcfg");
- if (IS_ERR(map)) {
- dev_err(f->dev, "No syscon regmap\n");
- goto err;
- }
-
- ret = regmap_read(map, DCFG_RCWSR1, &val);
- if (ret < 0)
- goto err;
-
- /* Strap bits 6:2 define SYS_PLL_RAT i.e frequency multiplier ratio
*/
- val = (val >> 2) & 0x1F;
- WARN(val == 0, "Strapping is zero: Cannot determine ratio");
-
- /* Compute system clock frequency */
- np = of_find_node_by_name(NULL, "clock-sysclk");
- if (!np)
- goto err;
-
- if (of_property_read_u32(np, "clock-frequency", &sysclk))
- goto err;
-
- sysclk = (sysclk * val) / 1000000; /* Convert sysclk to Mhz */
- dev_dbg(f->dev, "val: 0x%08x, sysclk: %dMhz\n", val, sysclk);
-
- /* Use IP bus only if PLL is 300MHz */
- if (sysclk == 300)
+ /* Use IP bus only if platform PLL is configured for 300 MHz, hence
we get 150 MHz */
+ if (clk_get_rate(clk_base) == 150000000)
f->devtype_data->quirks |= FSPI_QUIRK_USE_IP_ONLY;
-
- return;
-
-err:
- dev_err(f->dev, "Errata cannot be executed. Read via IP bus may not
work\n");
+ clk_put(clk_base);
}
static int nxp_fspi_default_setup(struct nxp_fspi *f)
@@ -994,10 +955,8 @@ static int nxp_fspi_default_setup(struct nxp_fspi
*f)
/*
* ERR050568: Flash access by FlexSPI AHB command may not work with
* platform frequency equal to 300 MHz on LS1028A.
- * LS1028A reuses LX2160A compatible entry. Make errata applicable
for
- * Layerscape LS1028A platform.
*/
- if (of_device_is_compatible(f->dev->of_node, "nxp,lx2160a-fspi"))
+ if (of_device_is_compatible(f->dev->of_node, "nxp,ls1028a-fspi"))
erratum_err050568(f);
/* Reset the module */
--
-michael