On 09/16/2016 02:29 PM, LABBE Corentin wrote:
> Hello
>
> I have some minor comment below:
>
> On Fri, Sep 16, 2016 at 12:39:25PM +0200, Cédric Le Goater wrote:
>> From: Alistair Popple <alistair@xxxxxxxxxxxx>
>>
>> This patch adds a simple device driver to expose the iBT interface on
>> Aspeed SOCs (AST2400 and AST2500) as a character device. Such SOCs are
>> commonly used as BMCs (BaseBoard Management Controllers) and this
>> driver implements the BMC side of the BT interface.
>>
>> The BT (Block Transfer) interface is used to perform in-band IPMI
>> communication between a host and its BMC. Entire messages are buffered
>> before sending a notification to the other end, host or BMC, that
>> there is data to be read. Usually, the host emits requests and the BMC
>> responses but the specification provides a mean for the BMC to send
>> SMS Attention (BMC-to-Host attention or System Management Software
>> attention) messages.
>>
>> For this purpose, the driver introduces a specific ioctl on the
>> device: 'BT_BMC_IOCTL_SMS_ATN' that can be used by the system running
>> on the BMC to signal the host of such an event.
>>
>> The device name defaults to '/dev/ipmi-bt-host'
>>
>> Signed-off-by: Alistair Popple <alistair@xxxxxxxxxxxx>
>> Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxx>
>> Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
>> [clg: - checkpatch fixes
>> - added a devicetree binding documentation
>> - replace 'bt_host' by 'bt_bmc' to reflect that the driver is
>> the BMC side of the IPMI BT interface
>> - renamed the device to 'ipmi-bt-host'
>> - introduced a temporary buffer to copy_{to,from}_user
>> - used platform_get_irq()
>> - moved the driver under drivers/char/ipmi/ but kept it as a misc
>> device
>> - changed the compatible cell to "aspeed,ast2400-bt-bmc"
>> ]
>> Signed-off-by: Cédric Le Goater <clg@xxxxxxxx>
>> ---
>>
>> Changes since v1:
>>
>> - replace 'bt_host' by 'bt_bmc' to reflect that the driver is
>> the BMC side of the IPMI BT interface
>> - renamed the device to 'ipmi-bt-host'
>> - introduced a temporary buffer to copy_{to,from}_user
>> - used platform_get_irq()
>> - moved the driver under drivers/char/ipmi/ but kept it as a misc
>> device
>> - changed the compatible cell to "aspeed,ast2400-bt-bmc"
>>
>> .../bindings/char/ipmi/aspeed,ast2400-bt-bmc.txt | 23 +
>> drivers/Makefile | 2 +-
>> drivers/char/ipmi/Kconfig | 7 +
>> drivers/char/ipmi/Makefile | 1 +
>> drivers/char/ipmi/bt-bmc.c | 486 +++++++++++++++++++++
>> include/uapi/linux/Kbuild | 1 +
>> include/uapi/linux/bt-bmc.h | 18 +
>> 7 files changed, 537 insertions(+), 1 deletion(-)
>> create mode 100644 Documentation/devicetree/bindings/char/ipmi/aspeed,ast2400-bt-bmc.txt
>> create mode 100644 drivers/char/ipmi/bt-bmc.c
>> create mode 100644 include/uapi/linux/bt-bmc.h
>>
>> diff --git a/Documentation/devicetree/bindings/char/ipmi/aspeed,ast2400-bt-bmc.txt b/Documentation/devicetree/bindings/char/ipmi/aspeed,ast2400-bt-bmc.txt
>> new file mode 100644
>> index 000000000000..fbbacd958240
>> --- /dev/null
>
> [..]
>
>> +#include <linux/module.h>
>> +#include <linux/moduleparam.h>
>> +#include <linux/errno.h>
>> +#include <linux/poll.h>
>> +#include <linux/sched.h>
>> +#include <linux/spinlock.h>
>> +#include <linux/slab.h>
>> +#include <linux/init.h>
>> +#include <linux/device.h>
>> +#include <linux/of.h>
>> +#include <linux/of_irq.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/io.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/delay.h>
>> +#include <linux/miscdevice.h>
>> +#include <linux/timer.h>
>> +#include <linux/jiffies.h>
>> +#include <linux/bt-bmc.h>
>
> Please sort them in alphabetical order, some of them seems not needed also (like spinlock.h)
sure. I will clean them up.
>> +
>> +/*
>> + * This is a BMC device used to communicate to the host
>> + */
>> +#define DEVICE_NAME "ipmi-bt-host"
>> +
>> +#define BT_IO_BASE 0xe4
>> +#define BT_IRQ 10
>> +
>> +#define BT_CR0 0x0
>> +#define BT_CR0_IO_BASE 16
>> +#define BT_CR0_IRQ 12
>> +#define BT_CR0_EN_CLR_SLV_RDP 0x8
>> +#define BT_CR0_EN_CLR_SLV_WRP 0x4
>> +#define BT_CR0_ENABLE_IBT 0x1
>> +#define BT_CR1 0x4
>> +#define BT_CR1_IRQ_H2B 0x01
>> +#define BT_CR1_IRQ_HBUSY 0x40
>> +#define BT_CR2 0x8
>> +#define BT_CR2_IRQ_H2B 0x01
>> +#define BT_CR2_IRQ_HBUSY 0x40
>> +#define BT_CR3 0xc
>> +#define BT_CTRL 0x10
>> +#define BT_CTRL_B_BUSY 0x80
>> +#define BT_CTRL_H_BUSY 0x40
>> +#define BT_CTRL_OEM0 0x20
>> +#define BT_CTRL_SMS_ATN 0x10
>> +#define BT_CTRL_B2H_ATN 0x08
>> +#define BT_CTRL_H2B_ATN 0x04
>> +#define BT_CTRL_CLR_RD_PTR 0x02
>> +#define BT_CTRL_CLR_WR_PTR 0x01
>> +#define BT_BMC2HOST 0x14
>> +#define BT_INTMASK 0x18
>> +#define BT_INTMASK_B2H_IRQEN 0x01
>> +#define BT_INTMASK_B2H_IRQ 0x02
>> +#define BT_INTMASK_BMC_HWRST 0x80
>
> Why to use 3 space after some define ?
The difference in alignment is to distinguish the register number from
the bits signification. Is that OK ?
> [..]
>
>> +
>> +#define BT_BMC_BUFFER_SIZE 256
>
> Put this define with others
>
> [..]
ok
>> +
>> +static irqreturn_t bt_bmc_irq(int irq, void *arg)
>> +{
>> + struct bt_bmc *bt_bmc = arg;
>> + uint32_t reg;
>
> u32 is prefered other uint32_t, do you have run checkpatch --strict ?
no. I just did and I see it is catching quite a few new issues. I will
send a v3 with fixes.
>> +
>> + reg = ioread32(bt_bmc->base + BT_CR2);
>> + reg &= BT_CR2_IRQ_H2B | BT_CR2_IRQ_HBUSY;
>> + if (!reg)
>> + return IRQ_NONE;
>> +
>> + /* ack pending IRQs */
>> + iowrite32(reg, bt_bmc->base + BT_CR2);
>> +
>> + wake_up(&bt_bmc->queue);
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
>> + struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + uint32_t reg;
>> + int rc;
>> +
>> + bt_bmc->irq = platform_get_irq(pdev, 0);
>> + if (!bt_bmc->irq)
>> + return -ENODEV;
>> +
>> + rc = devm_request_irq(dev, bt_bmc->irq, bt_bmc_irq, IRQF_SHARED,
>> + DEVICE_NAME, bt_bmc);
>> + if (rc < 0) {
>> + dev_warn(dev, "Unable to request IRQ %d\n", bt_bmc->irq);
>> + bt_bmc->irq = 0;
>> + return rc;
>> + }
>> +
>> + /* Configure IRQs on the bmc clearing the H2B and HBUSY bits;
>> + * H2B will be asserted when the bmc has data for us; HBUSY
>> + * will be cleared (along with B2H) when we can write the next
>> + * message to the BT buffer
>> + */
>
> This comment doesnt have the style recommended for new driver.
ah yes. I missed that one.
>> + reg = ioread32(bt_bmc->base + BT_CR1);
>> + reg |= BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY;
>> + iowrite32(reg, bt_bmc->base + BT_CR1);
>> +
>> + return 0;
>> +}
>> +
>> +static int bt_bmc_probe(struct platform_device *pdev)
>> +{
>> + struct bt_bmc *bt_bmc;
>> + struct device *dev;
>> + struct resource *res;
>> + int rc;
>> +
>> + if (!pdev || !pdev->dev.of_node)
>> + return -ENODEV;
>> +
>> + dev = &pdev->dev;
>> + dev_info(dev, "Found bt bmc device\n");
>> +
>> + bt_bmc = devm_kzalloc(dev, sizeof(*bt_bmc), GFP_KERNEL);
>> + if (!bt_bmc)
>> + return -ENOMEM;
>> +
>> + dev_set_drvdata(&pdev->dev, bt_bmc);
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + if (!res) {
>> + dev_err(dev, "Unable to find resources\n");
>> + rc = -ENXIO;
>> + goto out_free;
>> + }
>> +
>> + bt_bmc->base = devm_ioremap_resource(&pdev->dev, res);
>> + if (!bt_bmc->base) {
>> + rc = -ENOMEM;
>> + goto out_free;
>> + }
>> +
>> + init_waitqueue_head(&bt_bmc->queue);
>> +
>> + bt_bmc->miscdev.minor = MISC_DYNAMIC_MINOR,
>> + bt_bmc->miscdev.name = DEVICE_NAME,
>> + bt_bmc->miscdev.fops = &bt_bmc_fops,
>> + bt_bmc->miscdev.parent = dev;
>> + rc = misc_register(&bt_bmc->miscdev);
>> + if (rc) {
>> + dev_err(dev, "Unable to register device\n");
>
> Be more precise by saying misc device
ok
>
>> + goto out_unmap;
>> + }
>> +
>> + bt_bmc_config_irq(bt_bmc, pdev);
>> +
>> + if (bt_bmc->irq) {
>> + dev_info(dev, "Using IRQ %d\n", bt_bmc->irq);
>> + } else {
>> + dev_info(dev, "No IRQ; using timer\n");
>> + setup_timer(&bt_bmc->poll_timer, poll_timer,
>> + (unsigned long)bt_bmc);
>> + bt_bmc->poll_timer.expires = jiffies + msecs_to_jiffies(10);
>> + add_timer(&bt_bmc->poll_timer);
>> + }
>> +
>> + iowrite32((BT_IO_BASE << BT_CR0_IO_BASE) |
>> + (BT_IRQ << BT_CR0_IRQ) |
>> + BT_CR0_EN_CLR_SLV_RDP |
>> + BT_CR0_EN_CLR_SLV_WRP |
>> + BT_CR0_ENABLE_IBT,
>> + bt_bmc->base + BT_CR0);
>> +
>> + clr_b_busy(bt_bmc);
>> +
>> + return 0;
>> +
>> +out_unmap:
>> + devm_iounmap(&pdev->dev, bt_bmc->base);
>
> Why do you use devm_iounmap/devm_kfree since the interest with devm_ functions
> is that all cleanup is done when driver is removed.
Indeed. So I can cleanup bt_bmc_remove() also.
>> +
>> +out_free:
>> + devm_kfree(dev, bt_bmc);
>> + return rc;
>
> I think you should remove the space after this return
Thanks,
C.
> Regards
>
> Corentin Labbe
>
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