[U-Boot] [PATCH v3 1/7] riscv: Add a SYSCON driver for Andestech's PLIC

Auer, Lukas lukas.auer at aisec.fraunhofer.de
Mon Apr 1 09:08:49 UTC 2019


Hi Rick,

On Mon, 2019-04-01 at 16:24 +0800, Andes wrote:
> From: Rick Chen <rick at andestech.com>
> 
> The Platform-Level Interrupt Controller (PLIC)
> block holds memory-mapped claim and pending registers
> associated with software interrupt. It is required
> for handling IPI.
> 
> Signed-off-by: Rick Chen <rick at andestech.com>
> Cc: Greentime Hu <greentime at andestech.com>
> ---
> V3:
>  - Rename plic_init() as enable_ipi().
>  - Declase as static.
>  - Remove PLIC_BASE_GET() from enable_ipi().
> 

Take a look at patman [1], it makes it really easy to handle different
versions of a patch series. :)

[1]: https://github.com/u-boot/u-boot/blob/master/tools/patman/README

>  arch/riscv/Kconfig                   |   9 +++
>  arch/riscv/include/asm/global_data.h |   3 +
>  arch/riscv/include/asm/syscon.h      |   2 +-
>  arch/riscv/lib/Makefile              |   1 +
>  arch/riscv/lib/andes_plic.c          | 110 +++++++++++++++++++++++++++++++++++
>  5 files changed, 124 insertions(+), 1 deletion(-)
>  create mode 100644 arch/riscv/lib/andes_plic.c
> 
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 3a4470d..511768b 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -109,6 +109,15 @@ config SIFIVE_CLINT
>  	  The SiFive CLINT block holds memory-mapped control and status registers
>  	  associated with software and timer interrupts.
>  
> +config ANDES_PLIC
> +	bool
> +	depends on RISCV_MMODE
> +	select REGMAP
> +	select SYSCON
> +	help
> +	  The Andes PLIC block holds memory-mapped claim and pending registers
> +	  associated with software interrupt.
> +
>  config RISCV_RDTIME
>  	bool
>  	default y if RISCV_SMODE
> diff --git a/arch/riscv/include/asm/global_data.h b/arch/riscv/include/asm/global_data.h
> index 80e3165..b867910 100644
> --- a/arch/riscv/include/asm/global_data.h
> +++ b/arch/riscv/include/asm/global_data.h
> @@ -18,6 +18,9 @@ struct arch_global_data {
>  #ifdef CONFIG_SIFIVE_CLINT
>  	void __iomem *clint;	/* clint base address */
>  #endif
> +#ifdef CONFIG_ANDES_PLIC
> +	void __iomem *plic;	/* plic base address */
> +#endif
>  #ifdef CONFIG_SMP
>  	struct ipi_data ipi[CONFIG_NR_CPUS];
>  #endif
> diff --git a/arch/riscv/include/asm/syscon.h b/arch/riscv/include/asm/syscon.h
> index d311ee6..c1b4b86 100644
> --- a/arch/riscv/include/asm/syscon.h
> +++ b/arch/riscv/include/asm/syscon.h
> @@ -9,11 +9,11 @@
>  /*
>   * System controllers in a RISC-V system
>   *

nit: can you also drop the empty comment line above?

> - * So far only SiFive's Core Local Interruptor (CLINT) is defined.
>   */
>  enum {
>  	RISCV_NONE,
>  	RISCV_SYSCON_CLINT,	/* Core Local Interruptor (CLINT) */
> +	RISCV_SYSCON_PLIC,	/* Platform Level Interrupt Controller (PLIC) */
>  };
>  
>  #endif /* _ASM_SYSCON_H */
> diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
> index 35dbf64..1bf554b 100644
> --- a/arch/riscv/lib/Makefile
> +++ b/arch/riscv/lib/Makefile
> @@ -11,6 +11,7 @@ obj-$(CONFIG_CMD_GO) += boot.o
>  obj-y	+= cache.o
>  obj-$(CONFIG_RISCV_RDTIME) += rdtime.o
>  obj-$(CONFIG_SIFIVE_CLINT) += sifive_clint.o
> +obj-$(CONFIG_ANDES_PLIC) += andes_plic.o
>  obj-y	+= interrupts.o
>  obj-y	+= reset.o
>  obj-$(CONFIG_SBI_IPI) += sbi_ipi.o
> diff --git a/arch/riscv/lib/andes_plic.c b/arch/riscv/lib/andes_plic.c
> new file mode 100644
> index 0000000..67ab561
> --- /dev/null
> +++ b/arch/riscv/lib/andes_plic.c
> @@ -0,0 +1,110 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2019, Rick Chen <rick at andestech.com>
> + *
> + * U-Boot syscon driver for Andes's Platform Level Interrupt Controller (PLIC).
> + * The PLIC block holds memory-mapped claim and pending registers
> + * associated with software interrupt.
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <dm/device-internal.h>
> +#include <dm/lists.h>
> +#include <dm/uclass-internal.h>
> +#include <regmap.h>
> +#include <syscon.h>
> +#include <asm/io.h>
> +#include <asm/syscon.h>
> +#include <cpu.h>
> +
> +/* pending register */
> +#define PENDING_REG(base, hart)	((ulong)(base) + 0x1000 + (hart) * 8)
> +/* enable register */
> +#define ENABLE_REG(base, hart)	((ulong)(base) + 0x2000 + (hart) * 0x80)
> +/* claim register */
> +#define CLAIM_REG(base, hart)	((ulong)(base) + 0x200004 + (hart) * 0x1000)
> +
> +#define ENABLE_HART_IPI         (0x80808080)
> +#define SEND_IPI_TO_HART(hart)  (0x80>>hart)
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +static int init_plic(void);
> +
> +#define PLIC_BASE_GET(void)						\
> +	do {								\
> +		long *ret;						\
> +									\
> +		if (!gd->arch.plic) {					\
> +			ret = syscon_get_first_range(RISCV_SYSCON_PLIC); \
> +			if (IS_ERR(ret))				\
> +				return PTR_ERR(ret);			\
> +			gd->arch.plic = ret;				\
> +			init_plic();					\
> +		}							\
> +	} while (0)
> +
> +static int enable_ipi(int harts)
> +{
> +	int i;
> +	int en = ENABLE_HART_IPI;
> +
> +	for (i = 0; i < harts ;i++)
> +	{
> +		en = en >> i;
> +		writel(en, (void __iomem *)ENABLE_REG(gd->arch.plic, i));
> +	}
> +
> +	return 0;
> +}
> +
> +static int init_plic(void)
> +{
> +	struct udevice *dev;
> +	int ret;
> +
> +	ret = uclass_find_first_device(UCLASS_CPU, &dev);
> +	if (ret)
> +		return ret;
> +
> +	if (ret == 0 && dev != NULL) {
> +		ret = cpu_get_count(dev);

You should check first, if cpu_get_count() has returned an error before
using its return value.

> +		enable_ipi(ret);
> +		return 0;
> +	}
> +
> +	return -ENODEV;
> +}
> +
> +int riscv_send_ipi(int hart)
> +{
> +	PLIC_BASE_GET();
> +
> +	writel(SEND_IPI_TO_HART(hart), (void __iomem *)PENDING_REG(gd->arch.plic, gd->arch.boot_hart));
> +
> +	return 0;
> +}
> +
> +int riscv_clear_ipi(int hart)
> +{
> +	u32 source_id;
> +
> +	PLIC_BASE_GET();
> +
> +	source_id = readl((void __iomem *)CLAIM_REG(gd->arch.plic, hart));
> +	writel(source_id, (void __iomem *)CLAIM_REG(gd->arch.plic, hart));
> +
> +	return 0;
> +}
> +
> +static const struct udevice_id andes_plic_ids[] = {
> +	{ .compatible = "riscv,plic1", .data = RISCV_SYSCON_PLIC },

Would a compatible string of "andes,plic1" be more suitable?

> +	{ }
> +};
> +
> +U_BOOT_DRIVER(nds_plic) = {

nit: andes_plic

> +	.name		= "andes_plic",
> +	.id		= UCLASS_SYSCON,
> +	.of_match	= andes_plic_ids,
> +	.flags		= DM_FLAG_PRE_RELOC,
> +};

There are a couple of checkpatch issues in this patch. I have copied
the relevant ones below.

CHECK: spaces preferred around that '>>' (ctx:VxV)
#135: FILE: arch/riscv/lib/andes_plic.c:29:
+#define SEND_IPI_TO_HART(hart)  (0x80>>hart)

ERROR: that open brace { should be on the previous line
#158: FILE: arch/riscv/lib/andes_plic.c:52:
+	for (i = 0; i < harts ;i++)
+	{

ERROR: space required after that ';' (ctx:WxV)
#158: FILE: arch/riscv/lib/andes_plic.c:52:
+	for (i = 0; i < harts ;i++)

CHECK: Comparison to NULL could be written "dev"
#176: FILE: arch/riscv/lib/andes_plic.c:70:
+	if (ret == 0 && dev != NULL) {

WARNING: line over 80 characters
#189: FILE: arch/riscv/lib/andes_plic.c:83:
+	writel(SEND_IPI_TO_HART(hart), (void __iomem *)PENDING_REG(gd-
>arch.plic, gd->arch.boot_hart));

Thanks,
Lukas


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