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Date: Mon, 7 Jun 2010 16:05:15 +0100
From: Alan Cox <alan@...rguk.ukuu.org.uk>
To: Masayuki Ohtak <masa-korg@....okisemi.com>
Cc: LKML <linux-kernel@...r.kernel.org>,
Andrew <andrew.chih.howe.khor@...el.com>,
Intel OTC <joel.clark@...el.com>,
"Wang, Qi" <qi.wang@...el.com>,
"Wang, Yong Y" <yong.y.wang@...el.com>
Subject: Re: [PATCH] Topcliff PHUB: Generate PacketHub driver
O> +/* Status Register offset */
> +#define PHUB_STATUS (0x00)
> +/* Control Register offset */
> +#define PHUB_CONTROL (0x04)
> +/* Time out value for Status Register */
> +#define PHUB_TIMEOUT (0x05)
> +/* Enabling for writing ROM */
> +#define PCH_PHUB_ROM_WRITE_ENABLE (0x01)
> +/* Disabling for writing ROM */
> +#define PCH_PHUB_ROM_WRITE_DISABLE (0x00)
> +/* ROM data area start address offset */
> +#define PCH_PHUB_ROM_START_ADDR (0x14)
> +/* MAX number of INT_REDUCE_CONTROL registers */
> +#define MAX_NUM_INT_REDUCE_CONTROL_REG (128)
> +
> +#define PCI_DEVICE_ID_PCH1_PHUB (0x8801)
> +
> +#define PCH_MINOR_NOS (1)
> +#define CLKCFG_CAN_50MHZ (0x12000000)
> +#define CLKCFG_CANCLK_MASK (0xFF000000)
Style: constants don't need brackets - might also look more Linux like
tabbed out a bit
> +#define PCH_READ_REG(a) ioread32((pch_phub_base_address + a))
> +
> +#define PCH_WRITE_REG(a, b) iowrite32(a, (pch_phub_base_address + b))
These on the other hand do - but not where they are now
iowrite32((a), pcb_phub_base_address + (b))
(so that if a or b are expressions they are evaluated first)
> +struct pch_phub_reg {
> + u32 phub_id_reg; /* PHUB_ID register val */
> + u32 q_pri_val_reg; /* QUEUE_PRI_VAL register val */
> + u32 rc_q_maxsize_reg; /* RC_QUEUE_MAXSIZE register val */
> + u32 bri_q_maxsize_reg; /* BRI_QUEUE_MAXSIZE register val */
> + u32 comp_resp_timeout_reg; /* COMP_RESP_TIMEOUT register val */
> + u32 bus_slave_control_reg; /* BUS_SLAVE_CONTROL_REG register val */
> + u32 deadlock_avoid_type_reg; /* DEADLOCK_AVOID_TYPE register val */
> + u32 intpin_reg_wpermit_reg0; /* INTPIN_REG_WPERMIT register 0 val */
> + u32 intpin_reg_wpermit_reg1; /* INTPIN_REG_WPERMIT register 1 val */
> + u32 intpin_reg_wpermit_reg2; /* INTPIN_REG_WPERMIT register 2 val */
> + u32 intpin_reg_wpermit_reg3; /* INTPIN_REG_WPERMIT register 3 val */
> + /* INT_REDUCE_CONTROL registers val */
> + u32 int_reduce_control_reg[MAX_NUM_INT_REDUCE_CONTROL_REG];
> +#ifdef PCH_CAN_PCLK_50MHZ
> + u32 clkcfg_reg; /* CLK CFG register val */
> +#endif
> +} g_pch_phub_reg;
Stylewise the kernel doesn't use the g_ convention that many Windows
people do, so lose the g_
> +s32 pch_phub_opencount; /* check whether opened or not */
> +u32 pch_phub_base_address;
> +u32 pch_phub_extrom_base_address;
> +s32 pch_phub_suspended;
Any reason these can't be in the struct ?
> +
> +struct device *dev_dbg;
Not a good name for a global variable as it will clash with others
> +DEFINE_SPINLOCK(pch_phub_lock); /* for spin lock */
Can this be static or in the struct ?
> +
> +/**
> + * file_operations structure initialization
> + */
> +const struct file_operations pch_phub_fops = {
> + .owner = THIS_MODULE,
> + .open = pch_phub_open,
> + .release = pch_phub_release,
> + .ioctl = pch_phub_ioctl,
> +};
static const ?
> +/*--------------------------------------------
> + exported function prototypes
> +--------------------------------------------*/
They start 'static' I don't think they are exportdd !
> +static int __devinit pch_phub_probe(struct pci_dev *pdev, const
> + struct pci_device_id *id);
> +static void __devexit pch_phub_remove(struct pci_dev *pdev);
> +static int pch_phub_suspend(struct pci_dev *pdev, pm_message_t state);
> +static int pch_phub_resume(struct pci_dev *pdev);
> +static struct pci_driver pch_phub_driver = {
> + .name = "pch_phub",
> + .id_table = pch_phub_pcidev_id,
> + .probe = pch_phub_probe,
> + .remove = __devexit_p(pch_phub_remove),
> +#ifdef CONFIG_PM
> + .suspend = pch_phub_suspend,
> + .resume = pch_phub_resume
> +#endif
> +};
> +
> +static int __init pch_phub_pci_init(void);
> +static void __exit pch_phub_pci_exit(void);
> +
> +MODULE_DESCRIPTION("PCH PACKET HUB PCI Driver");
> +MODULE_LICENSE("GPL");
> +module_init(pch_phub_pci_init);
> +module_exit(pch_phub_pci_exit);
> +module_param(pch_phub_major_no, int, S_IRUSR | S_IWUSR);
If you migrated the module registration/PCI registration to the bottom of
the file you could avoid the forward declations and make the code easier
to follow ?
> +void pch_phub_read_modify_write_reg(unsigned long reg_addr_offset,
> + unsigned long data, unsigned long mask)
> +{
> + unsigned long reg_addr = pch_phub_base_address + reg_addr_offset;
> + iowrite32(((ioread32((void __iomem *)reg_addr) & ~mask)) | data,
> + (void __iomem *)reg_addr);
When you have that many casts in a line it's perhaps a hint you have the
types wrong initially. At the very least reg_addr should be void __iomem,
and probably pch_phub_base_address should be
It would probably make sense to pass a pointer to your struct pch_hub_reg
and use that to hold the base address. Then if you ever get a box with
two in some future design it won't be a disaster
> +void pch_phub_save_reg_conf(void)
Ditto
> +#ifdef PCH_CAN_PCLK_50MHZ
> + /* save clk cfg register */
> + g_pch_phub_reg.clkcfg_reg = PCH_READ_REG(CLKCFG_REG_OFFSET);
> +#endif
This makes it hard to build one kernel for everything
> + return;
> +}
> +void pch_phub_restore_reg_conf(void)
> +{
> + u32 i = 0;
Why = 0, if you do that here you may hide initialisation errors from
future changes ?
> +/** pch_phub_read_serial_rom - Implements the functionality of reading Serial
> + * ROM.
> + * @offset_address: Contains the Serial ROM address offset value
> + * @data: Contains the Serial ROM value
> + */
> +int pch_phub_read_serial_rom(unsigned long offset_address, unsigned char *data)
> +{
> + unsigned long mem_addr = pch_phub_extrom_base_address + offset_address;
> +
> + dev_dbg(dev_dbg,
> + "pch_phub_read_serial_rom:mem_addr=0x%08x\n", (u32)mem_addr);
> + *data = ioread8((void __iomem *)mem_addr);
Same comments about casts
> +int pch_phub_ioctl(struct inode *inode, struct file *file,
> + unsigned int cmd, unsigned long arg)
> +{
> + int ret_value = 0;
> + struct pch_phub_reqt *p_pch_phub_reqt;
> + unsigned long addr_offset;
This will change size on 32/64bit boxes makign your copy a bit
problematic
> + p_pch_phub_reqt = (struct pch_phub_reqt *)arg;
> + ret_value = copy_from_user((void *)&addr_offset,
> + (void *)&p_pch_phub_reqt->addr_offset,
> + sizeof(addr_offset));
> + if (ret_value) {
> + /* End of Access area check */
Remember here ioctl isn't single threaded so you may want to double check
some of these
> +struct pch_phub_reqt {
> + unsigned long addr_offset; /*specifies the register address
> + offset */
> + unsigned long data; /*specifies the data */
> + unsigned long mask; /*specifies the mask */
If they may need to be long make them u64. That way 32 and 64bit systems
get the same ioctl structure and life is good.
> +};
> +
> +/* exported function prototypes */
> +int pch_phub_open(struct inode *inode, struct file *file);
> +int pch_phub_release(struct inode *inode, struct file *file);
> +int pch_phub_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
> + unsigned long arg);
You have various other functions that are not static - if they should be
then make them static
Alan
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