[PATCH v2] soc: imx8m: Probe the SoC driver as platform driver
Saravana Kannan
saravanak at google.com
Wed Sep 25 16:03:22 PDT 2024
On Wed, Sep 25, 2024 at 3:06 PM Marek Vasut <marex at denx.de> wrote:
>
> With driver_async_probe=* on kernel command line, the following trace is
> produced because on i.MX8M Plus hardware because the soc-imx8m.c driver
> calls of_clk_get_by_name() which returns -EPROBE_DEFER because the clock
> driver is not yet probed. This was not detected during regular testing
> without driver_async_probe.
>
> Convert the SoC code to platform driver and instantiate a platform device
> in its current device_initcall() to probe the platform driver. Rework
> .soc_revision callback to always return valid error code and return SoC
> revision via parameter. This way, if anything in the .soc_revision callback
> return -EPROBE_DEFER, it gets propagated to .probe and the .probe will get
> retried later.
I'm assuming you tested this patch and it works? Did you see any other
issues with driver_async_probe=* ?
Does this improve your probe/boot time? Some stats on that would be nice.
>
> "
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 1 at drivers/soc/imx/soc-imx8m.c:115 imx8mm_soc_revision+0xdc/0x180
> CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.11.0-next-20240924-00002-g2062bb554dea #603
> Hardware name: DH electronics i.MX8M Plus DHCOM Premium Developer Kit (3) (DT)
> pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : imx8mm_soc_revision+0xdc/0x180
> lr : imx8mm_soc_revision+0xd0/0x180
> sp : ffff8000821fbcc0
> x29: ffff8000821fbce0 x28: 0000000000000000 x27: ffff800081810120
> x26: ffff8000818a9970 x25: 0000000000000006 x24: 0000000000824311
> x23: ffff8000817f42c8 x22: ffff0000df8be210 x21: fffffffffffffdfb
> x20: ffff800082780000 x19: 0000000000000001 x18: ffffffffffffffff
> x17: ffff800081fff418 x16: ffff8000823e1000 x15: ffff0000c03b65e8
> x14: ffff0000c00051b0 x13: ffff800082790000 x12: 0000000000000801
> x11: ffff80008278ffff x10: ffff80008209d3a6 x9 : ffff80008062e95c
> x8 : ffff8000821fb9a0 x7 : 0000000000000000 x6 : 00000000000080e3
> x5 : ffff0000df8c03d8 x4 : 0000000000000000 x3 : 0000000000000000
> x2 : 0000000000000000 x1 : fffffffffffffdfb x0 : fffffffffffffdfb
> Call trace:
> imx8mm_soc_revision+0xdc/0x180
> imx8_soc_init+0xb0/0x1e0
> do_one_initcall+0x94/0x1a8
> kernel_init_freeable+0x240/0x2a8
> kernel_init+0x28/0x140
> ret_from_fork+0x10/0x20
> ---[ end trace 0000000000000000 ]---
> SoC: i.MX8MP revision 1.1
> "
>
> Signed-off-by: Marek Vasut <marex at denx.de>
> ---
> Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
> Cc: Arnd Bergmann <arnd at arndb.de>
> Cc: Fabio Estevam <festevam at gmail.com>
> Cc: Jeff Johnson <quic_jjohnson at quicinc.com>
> Cc: Neil Armstrong <neil.armstrong at linaro.org>
> Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
> Cc: Saravana Kannan <saravanak at google.com>
> Cc: Sascha Hauer <s.hauer at pengutronix.de>
> Cc: Shawn Guo <shawnguo at kernel.org>
> Cc: imx at lists.linux.dev
> Cc: linux-arm-kernel at lists.infradead.org
> Cc: linux-kernel at vger.kernel.org
> ---
> V2: Use the platform device approach instead of late_initcall
> ---
> drivers/soc/imx/soc-imx8m.c | 92 ++++++++++++++++++++++++++++---------
> 1 file changed, 70 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/soc/imx/soc-imx8m.c b/drivers/soc/imx/soc-imx8m.c
> index fe111bae38c8e..170970d4955c6 100644
> --- a/drivers/soc/imx/soc-imx8m.c
> +++ b/drivers/soc/imx/soc-imx8m.c
> @@ -30,7 +30,7 @@
>
> struct imx8_soc_data {
> char *name;
> - u32 (*soc_revision)(void);
> + int (*soc_revision)(u32 *socrev);
> };
>
> static u64 soc_uid;
> @@ -51,24 +51,29 @@ static u32 imx8mq_soc_revision_from_atf(void)
> static inline u32 imx8mq_soc_revision_from_atf(void) { return 0; };
> #endif
>
> -static u32 __init imx8mq_soc_revision(void)
> +static int imx8mq_soc_revision(u32 *socrev)
> {
> struct device_node *np;
> void __iomem *ocotp_base;
> u32 magic;
> u32 rev;
> struct clk *clk;
> + int ret;
>
> np = of_find_compatible_node(NULL, NULL, "fsl,imx8mq-ocotp");
> if (!np)
> - return 0;
> + return -EINVAL;
>
> ocotp_base = of_iomap(np, 0);
> - WARN_ON(!ocotp_base);
> + if (!ocotp_base) {
> + ret = -EINVAL;
> + goto err_iomap;
> + }
> +
> clk = of_clk_get_by_name(np, NULL);
> if (IS_ERR(clk)) {
> - WARN_ON(IS_ERR(clk));
> - return 0;
> + ret = PTR_ERR(clk);
> + goto err_clk;
> }
>
> clk_prepare_enable(clk);
> @@ -88,32 +93,45 @@ static u32 __init imx8mq_soc_revision(void)
> soc_uid <<= 32;
> soc_uid |= readl_relaxed(ocotp_base + OCOTP_UID_LOW);
>
> + *socrev = rev;
> +
> clk_disable_unprepare(clk);
> clk_put(clk);
> iounmap(ocotp_base);
> of_node_put(np);
>
> - return rev;
> + return 0;
> +
> +err_clk:
> + iounmap(ocotp_base);
> +err_iomap:
> + of_node_put(np);
> + return ret;
> }
>
> -static void __init imx8mm_soc_uid(void)
> +static int imx8mm_soc_uid(void)
> {
> void __iomem *ocotp_base;
> struct device_node *np;
> struct clk *clk;
> + int ret = 0;
> u32 offset = of_machine_is_compatible("fsl,imx8mp") ?
> IMX8MP_OCOTP_UID_OFFSET : 0;
>
> np = of_find_compatible_node(NULL, NULL, "fsl,imx8mm-ocotp");
> if (!np)
> - return;
> + return -EINVAL;
>
> ocotp_base = of_iomap(np, 0);
> - WARN_ON(!ocotp_base);
> + if (!ocotp_base) {
> + ret = -EINVAL;
> + goto err_iomap;
> + }
> +
> clk = of_clk_get_by_name(np, NULL);
> if (IS_ERR(clk)) {
> - WARN_ON(IS_ERR(clk));
> - return;
> + ret = PTR_ERR(clk);
> + goto err_clk;
> }
>
> clk_prepare_enable(clk);
> @@ -124,31 +142,41 @@ static void __init imx8mm_soc_uid(void)
>
> clk_disable_unprepare(clk);
> clk_put(clk);
> +
> +err_clk:
> iounmap(ocotp_base);
> +err_iomap:
> of_node_put(np);
> +
> + return ret;
> }
>
> -static u32 __init imx8mm_soc_revision(void)
> +static int imx8mm_soc_revision(u32 *socrev)
> {
> struct device_node *np;
> void __iomem *anatop_base;
> - u32 rev;
> + int ret;
>
> np = of_find_compatible_node(NULL, NULL, "fsl,imx8mm-anatop");
> if (!np)
> - return 0;
> + return -EINVAL;
>
> anatop_base = of_iomap(np, 0);
> - WARN_ON(!anatop_base);
> + if (!anatop_base) {
> + ret = -EINVAL;
> + goto err_iomap;
> + }
>
> - rev = readl_relaxed(anatop_base + ANADIG_DIGPROG_IMX8MM);
> + *socrev = readl_relaxed(anatop_base + ANADIG_DIGPROG_IMX8MM);
>
> iounmap(anatop_base);
> of_node_put(np);
>
> - imx8mm_soc_uid();
> + return imx8mm_soc_uid();
>
> - return rev;
> +err_iomap:
> + of_node_put(np);
> + return ret;
> }
>
> static const struct imx8_soc_data imx8mq_soc_data = {
> @@ -184,7 +212,7 @@ static __maybe_unused const struct of_device_id imx8_soc_match[] = {
> kasprintf(GFP_KERNEL, "%d.%d", (soc_rev >> 4) & 0xf, soc_rev & 0xf) : \
> "unknown"
>
> -static int __init imx8_soc_init(void)
> +static int imx8m_soc_probe(struct platform_device *pdev)
> {
> struct soc_device_attribute *soc_dev_attr;
> struct soc_device *soc_dev;
> @@ -212,8 +240,11 @@ static int __init imx8_soc_init(void)
> data = id->data;
> if (data) {
> soc_dev_attr->soc_id = data->name;
> - if (data->soc_revision)
> - soc_rev = data->soc_revision();
> + if (data->soc_revision) {
> + ret = data->soc_revision(&soc_rev);
> + if (ret)
> + goto free_soc;
> + }
> }
>
> soc_dev_attr->revision = imx8_revision(soc_rev);
> @@ -251,6 +282,23 @@ static int __init imx8_soc_init(void)
> kfree(soc_dev_attr);
> return ret;
> }
> +
> +static struct platform_driver imx8m_soc_driver = {
> + .probe = imx8m_soc_probe,
> + .driver = {
> + .name = "imx8m-soc",
> + },
> +};
> +module_platform_driver(imx8m_soc_driver);
This just translates to a module_init() when compiled as a module.
>
> +
> +static int __init imx8_soc_init(void)
> +{
> + struct platform_device *pdev;
> +
> + pdev = platform_device_register_simple("imx8m-soc", -1, NULL, 0);
> +
> + return IS_ERR(pdev) ? PTR_ERR(pdev) : 0;
> +}
> device_initcall(imx8_soc_init);
This also translates to a module_init() when compiled as a module.
I've never seen a module with two module_init()s and I'm pretty sure
that doesn't work. I'm guessing this driver doesn't support tristate
in its current state. But with this patch, it should work as a module
too. Why not add support for that too?
Why not just do both of these things in one initcall?
platform_create_bundle() doesn't work with deferred probing though. So
just do one initcall that adds the device and registers the platform
driver.
-Saravana
> MODULE_DESCRIPTION("NXP i.MX8M SoC driver");
> MODULE_LICENSE("GPL");
> --
> 2.45.2
>
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