RE: [PATCH 3/3] edac: Supporting AST2400 and AST2600 edac driver

[Troy Lee <troy_lee@aspeedtech.com>]

Hi Andrew,

Great suggestion, responses inline below. We'll remove build-time SoC dependency driver code and submit an updated v2 patch.

Thanks,
Troy Lee

> -----Original Message-----
> From: Andrew Jeffery <andrew@aj.id.au>
> Sent: Tuesday, December 1, 2020 9:12 AM
> To: Troy Lee <troy_lee@aspeedtech.com>; Stefan M Schaeckeler
> <sschaeck@cisco.com>; Rob Herring <robh+dt@kernel.org>; Joel Stanley
> <joel@jms.id.au>; Borislav Petkov <bp@alien8.de>; Mauro Carvalho Chehab
> <mchehab@kernel.org>; Tony Luck <tony.luck@intel.com>; James Morse
> <james.morse@arm.com>; Robert Richter <rrichter@marvell.com>; open
> list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS
> <devicetree@vger.kernel.org>; moderated list:ARM/ASPEED MACHINE
> SUPPORT <linux-arm-kernel@lists.infradead.org>; moderated
> list:ARM/ASPEED MACHINE SUPPORT <linux-aspeed@lists.ozlabs.org>; open
> list <linux-kernel@vger.kernel.org>; open list:EDAC-CORE
> <linux-edac@vger.kernel.org>
> Cc: leetroy@gmail.com; Ryan Chen <ryan_chen@aspeedtech.com>
> Subject: Re: [PATCH 3/3] edac: Supporting AST2400 and AST2600 edac driver
> 
> Hi Troy,
> 
> I like the idea of expanding the driver's support to cover the other SoC
> generations, but not at the cost of making the build of the driver SoC-specific.
> I've made some comments below in this regard.
> 
> On Mon, 30 Nov 2020, at 19:03, Troy Lee wrote:
> > Adding AST2400 and AST2600 edac driver support.
> >
> > Signed-off-by: Troy Lee <troy_lee@aspeedtech.com>
> > ---
> >  drivers/edac/Kconfig       |   6 +-
> >  drivers/edac/aspeed_edac.c | 114
> > +++++++++++++++++++++++++++++--------
> >  2 files changed, 94 insertions(+), 26 deletions(-)
> >
> > diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig index
> > fc30f2ef9782..8ea70746d0bf 100644
> > --- a/drivers/edac/Kconfig
> > +++ b/drivers/edac/Kconfig
> > @@ -508,10 +508,10 @@ config EDAC_QCOM
> >  	  health, you should probably say 'Y' here.
> >
> >  config EDAC_ASPEED
> > -	tristate "Aspeed AST 2500 SoC"
> > -	depends on MACH_ASPEED_G5
> > +	tristate "Aspeed AST BMC SoC"
> > +	depends on (MACH_ASPEED_G4 || MACH_ASPEED_G5 ||
> MACH_ASPEED_G6)
> >  	help
> > -	  Support for error detection and correction on the Aspeed AST 2500 SoC.
> > +	  Support for error detection and correction on the Aspeed AST BMC SoC.
> >
> >  	  First, ECC must be configured in the bootloader. Then, this driver
> >  	  will expose error counters via the EDAC kernel framework.
> > diff --git a/drivers/edac/aspeed_edac.c b/drivers/edac/aspeed_edac.c
> > index fbec28dc661d..03a3c12f6bf6 100644
> > --- a/drivers/edac/aspeed_edac.c
> > +++ b/drivers/edac/aspeed_edac.c
> > @@ -14,12 +14,11 @@
> >  #include <linux/regmap.h>
> >  #include "edac_module.h"
> >
> > -
> >  #define DRV_NAME "aspeed-edac"
> >
> > -
> >  #define ASPEED_MCR_PROT        0x00 /* protection key register */
> >  #define ASPEED_MCR_CONF        0x04 /* configuration register */
> > +#define ASPEED_MCR_REQ         0x08 /* Graphics Memory Protection
> register */
> >  #define ASPEED_MCR_INTR_CTRL   0x50 /* interrupt control/status
> register */
> >  #define ASPEED_MCR_ADDR_UNREC  0x58 /* address of first
> un-recoverable error */
> >  #define ASPEED_MCR_ADDR_REC    0x5c /* address of last recoverable
> error */
> > @@ -34,10 +33,8 @@
> >  #define ASPEED_MCR_INTR_CTRL_CNT_UNREC GENMASK(15, 12)
> #define
> > ASPEED_MCR_INTR_CTRL_ENABLE  (BIT(0) | BIT(1))
> >
> > -
> >  static struct regmap *aspeed_regmap;
> >
> > -
> >  static int regmap_reg_write(void *context, unsigned int reg, unsigned
> > int val)  {
> >  	void __iomem *regs = (void __iomem *)context; @@ -53,7 +50,6 @@
> > static int regmap_reg_write(void *context, unsigned int reg, unsigned
> > int val)
> >  	return 0;
> >  }
> >
> > -
> >  static int regmap_reg_read(void *context, unsigned int reg, unsigned
> > int *val)  {
> >  	void __iomem *regs = (void __iomem *)context; @@ -63,6 +59,76 @@
> > static int regmap_reg_read(void *context, unsigned int reg, unsigned
> > int *val)
> >  	return 0;
> >  }
> >
> > +extern void aspeed_sdmc_disable_mem_protection(u8 req) {
> > +	u32 req_val = 0;
> > +
> > +	regmap_read(aspeed_regmap, ASPEED_MCR_REQ, &req_val);
> > +
> > +	req_val &= ~BIT(req);
> > +
> > +	regmap_write(aspeed_regmap, ASPEED_MCR_REQ, req_val); }
> > +EXPORT_SYMBOL(aspeed_sdmc_disable_mem_protection);
> > +
> > +static const u32 ast2400_dram_table[] = {
> > +	0x04000000,	//64MB
> > +	0x08000000,	//128MB
> > +	0x10000000,	//256MB
> > +	0x20000000,	//512MB
> > +};
> 
> You could perhaps save us from the size comments here by using e.g.
> 
> static const u32 ast2400_dram_table[] = {
>     64 << 20,
>     128 << 20,
>     256 << 20,
>     512 << 20,
> };
> 
Fixed all in v2.

> > +
> > +static const u32 ast2500_dram_table[] = {
> > +	0x08000000,	//128MB
> > +	0x10000000,	//256MB
> > +	0x20000000,	//512MB
> > +	0x40000000,	//1024MB
> > +};
> > +
> > +static const u32 ast2600_dram_table[] = {
> > +	0x10000000,	//256MB
> > +	0x20000000,	//512MB
> > +	0x40000000,	//1024MB
> > +	0x80000000,	//2048MB
> > +};
> > +
> > +extern u32 aspeed_get_dram_size(void) {
> > +	u32 reg04;
> > +	u32 size;
> > +
> > +	regmap_read(aspeed_regmap, ASPEED_MCR_CONF, &reg04);
> > +
> > +#if defined(CONFIG_MACH_ASPEED_G6)
> > +	size = ast2600_dram_table[reg04 & 0x3]; #elif
> > +defined(CONFIG_MACH_ASPEED_G5)
> > +	size = ast2500_dram_table[reg04 & 0x3]; #else
> > +	size = ast2400_dram_table[reg04 & 0x3]; #endif
> > +	return size;
> > +}
> > +EXPORT_SYMBOL(aspeed_get_dram_size);
> 
> The driver must support running on any of the SoC generations without being
> recompiled. This requires the driver be compiled for a specific SoC generation.
> 
> The right way to do this is to use the OF match table data. Please fix it.
> 
Fixed in v2, driver can check the DRAM controller hardware version from MCR_CONF [31:28].

> > +
> > +static const u32 aspeed_vga_table[] = {
> > +	0x800000,	//8MB
> > +	0x1000000,	//16MB
> > +	0x2000000,	//32MB
> > +	0x4000000,	//64MB
> > +};
> > +
> > +extern u32 aspeed_get_vga_size(void)
> > +{
> > +	u32 reg04;
> > +	u32 size;
> > +
> > +	regmap_read(aspeed_regmap, ASPEED_MCR_CONF, &reg04);
> > +
> > +	size = aspeed_vga_table[((reg04 & 0xC) >> 2)];
> > +	return size;
> > +}
> > +EXPORT_SYMBOL(aspeed_get_vga_size);
> > +
> >  static bool regmap_is_volatile(struct device *dev, unsigned int reg)
> > {
> >  	switch (reg) {
> > @@ -209,8 +275,8 @@ static int config_irq(void *ctx, struct
> > platform_device *pdev)
> >  	/* register interrupt handler */
> >  	irq = platform_get_irq(pdev, 0);
> >  	dev_dbg(&pdev->dev, "got irq %d\n", irq);
> > -	if (irq < 0)
> > -		return irq;
> > +	if (!irq)
> > +		return -ENODEV;
> 
> The documentation for platform_get_irq() says "Return: IRQ number on
> success, negative error number on failure."
> 
> So this change doesn't look right.
> 
Fixed in v2.

> >
> >  	rc = devm_request_irq(&pdev->dev, irq, mcr_isr, IRQF_TRIGGER_HIGH,
> >  			      DRV_NAME, ctx);
> > @@ -239,7 +305,11 @@ static int init_csrows(struct mem_ctl_info *mci)
> >  	int rc;
> >
> >  	/* retrieve info about physical memory from device tree */
> > -	np = of_find_node_by_path("/memory");
> > +#ifdef CONFIG_MACH_ASPEED_G4
> > +	np = of_find_node_by_path("/memory@40000000");
> > +#else
> > +	np = of_find_node_by_path("/memory@80000000");
> > +#endif
> 
> Again, this makes the driver SoC-specific at compile time, and that's not going
> to fly. If we need it, this should be solved with a phandle to the appropriate
> memory node.
> 
Fixed in v2 by using of_find_node_by_name(NULL, "memory") instead.

> >  	if (!np) {
> >  		dev_err(mci->pdev, "dt: missing /memory node\n");
> >  		return -ENODEV;
> > @@ -281,11 +351,19 @@ static int aspeed_probe(struct platform_device
> *pdev)
> >  	struct device *dev = &pdev->dev;
> >  	struct edac_mc_layer layers[2];
> >  	struct mem_ctl_info *mci;
> > +	struct device_node *np;
> > +	struct resource *res;
> >  	void __iomem *regs;
> > -	u32 reg04;
> >  	int rc;
> >
> > -	regs = devm_platform_ioremap_resource(pdev, 0);
> > +	/* setup regmap */
> > +	np = dev->of_node;
> > +
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	if (!res)
> > +		return -ENOENT;
> > +
> > +	regs = devm_ioremap_resource(dev, res);
> >  	if (IS_ERR(regs))
> >  		return PTR_ERR(regs);
> 
> Why is this change necessary?
> 
Not necessary, so I'll reverted this part of change in v2.

> >
> > @@ -294,13 +372,6 @@ static int aspeed_probe(struct platform_device
> *pdev)
> >  	if (IS_ERR(aspeed_regmap))
> >  		return PTR_ERR(aspeed_regmap);
> >
> > -	/* bail out if ECC mode is not configured */
> > -	regmap_read(aspeed_regmap, ASPEED_MCR_CONF, &reg04);
> > -	if (!(reg04 & ASPEED_MCR_CONF_ECC)) {
> > -		dev_err(&pdev->dev, "ECC mode is not configured in u-boot\n");
> > -		return -EPERM;
> > -	}
> > -
> 
> Why shouldn't we do this check?
The driver can handle both ECC on and off, so this check might not be necessary.

> >  	edac_op_state = EDAC_OPSTATE_INT;
> >
> >  	/* allocate & init EDAC MC data structure */ @@ -373,13 +444,13 @@
> > static int aspeed_remove(struct platform_device *pdev)
> >  	return 0;
> >  }
> >
> > -
> >  static const struct of_device_id aspeed_of_match[] = {
> > +	{ .compatible = "aspeed,ast2400-sdram-edac" },
> >  	{ .compatible = "aspeed,ast2500-sdram-edac" },
> > +	{ .compatible = "aspeed,ast2600-sdram-edac" },
> 
> The .data member of struct of_device_id is where you need to attach your
> SoC-generation-specific data.
> 
> Cheers,
> 
> Andrew
> 
> >  	{},
> >  };
> >
> > -
> >  static struct platform_driver aspeed_driver = {
> >  	.driver		= {
> >  		.name	= DRV_NAME,
> > @@ -395,18 +466,15 @@ static int __init aspeed_init(void)
> >  	return platform_driver_register(&aspeed_driver);
> >  }
> >
> > -
> >  static void __exit aspeed_exit(void)
> >  {
> >  	platform_driver_unregister(&aspeed_driver);
> >  }
> >
> > -
> >  module_init(aspeed_init);
> >  module_exit(aspeed_exit);
> >
> > -
> >  MODULE_LICENSE("GPL");
> >  MODULE_AUTHOR("Stefan Schaeckeler <sschaeck@cisco.com>");
> > -MODULE_DESCRIPTION("Aspeed AST2500 EDAC driver");
> > +MODULE_DESCRIPTION("Aspeed EDAC driver");
> >  MODULE_VERSION("1.0");
> > --
> > 2.17.1
> >
> >