Hi Corey,
On Fri, 3 Sept 2021 at 05:10, Joel Stanley <j...@jms.id.au> wrote:
>
> This driver was originally written to use the regmap abstraction with no
> clear benefit. As the registers are always mmio and there is no sharing
> of the region with other devices, we can safely read and write without
> the locking that regmap provides.
>
> This reduces the code size of the driver by about 25%.
Do you have any feedback on this one?
Cheers,
Joel
>
> Signed-off-by: Joel Stanley <j...@jms.id.au>
> ---
> drivers/char/ipmi/bt-bmc.c | 68 +++++++++-----------------------------
> 1 file changed, 16 insertions(+), 52 deletions(-)
>
> diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
> index 6e3d247b55d1..fb771ce6f7bf 100644
> --- a/drivers/char/ipmi/bt-bmc.c
> +++ b/drivers/char/ipmi/bt-bmc.c
> @@ -8,13 +8,11 @@
> #include <linux/errno.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> -#include <linux/mfd/syscon.h>
> #include <linux/miscdevice.h>
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/platform_device.h>
> #include <linux/poll.h>
> -#include <linux/regmap.h>
> #include <linux/sched.h>
> #include <linux/timer.h>
>
> @@ -59,8 +57,7 @@
> struct bt_bmc {
> struct device dev;
> struct miscdevice miscdev;
> - struct regmap *map;
> - int offset;
> + void __iomem *base;
> int irq;
> wait_queue_head_t queue;
> struct timer_list poll_timer;
> @@ -69,29 +66,14 @@ struct bt_bmc {
>
> static atomic_t open_count = ATOMIC_INIT(0);
>
> -static const struct regmap_config bt_regmap_cfg = {
> - .reg_bits = 32,
> - .val_bits = 32,
> - .reg_stride = 4,
> -};
> -
> static u8 bt_inb(struct bt_bmc *bt_bmc, int reg)
> {
> - uint32_t val = 0;
> - int rc;
> -
> - rc = regmap_read(bt_bmc->map, bt_bmc->offset + reg, &val);
> - WARN(rc != 0, "regmap_read() failed: %d\n", rc);
> -
> - return rc == 0 ? (u8) val : 0;
> + return readb(bt_bmc->base + reg);
> }
>
> static void bt_outb(struct bt_bmc *bt_bmc, u8 data, int reg)
> {
> - int rc;
> -
> - rc = regmap_write(bt_bmc->map, bt_bmc->offset + reg, data);
> - WARN(rc != 0, "regmap_write() failed: %d\n", rc);
> + writeb(data, bt_bmc->base + reg);
> }
>
> static void clr_rd_ptr(struct bt_bmc *bt_bmc)
> @@ -376,18 +358,15 @@ static irqreturn_t bt_bmc_irq(int irq, void *arg)
> {
> struct bt_bmc *bt_bmc = arg;
> u32 reg;
> - int rc;
>
> - rc = regmap_read(bt_bmc->map, bt_bmc->offset + BT_CR2, ®);
> - if (rc)
> - return IRQ_NONE;
> + reg = readl(bt_bmc->base + BT_CR2);
>
> reg &= BT_CR2_IRQ_H2B | BT_CR2_IRQ_HBUSY;
> if (!reg)
> return IRQ_NONE;
>
> /* ack pending IRQs */
> - regmap_write(bt_bmc->map, bt_bmc->offset + BT_CR2, reg);
> + writel(reg, bt_bmc->base + BT_CR2);
>
> wake_up(&bt_bmc->queue);
> return IRQ_HANDLED;
> @@ -398,6 +377,7 @@ static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
> {
> struct device *dev = &pdev->dev;
> int rc;
> + u32 reg;
>
> bt_bmc->irq = platform_get_irq_optional(pdev, 0);
> if (bt_bmc->irq < 0)
> @@ -417,11 +397,11 @@ static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
> * will be cleared (along with B2H) when we can write the next
> * message to the BT buffer
> */
> - rc = regmap_update_bits(bt_bmc->map, bt_bmc->offset + BT_CR1,
> - (BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY),
> - (BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY));
> + reg = readl(bt_bmc->base + BT_CR1);
> + reg |= BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY;
> + writel(reg, bt_bmc->base + BT_CR1);
>
> - return rc;
> + return 0;
> }
>
> static int bt_bmc_probe(struct platform_device *pdev)
> @@ -439,25 +419,9 @@ static int bt_bmc_probe(struct platform_device *pdev)
>
> dev_set_drvdata(&pdev->dev, bt_bmc);
>
> - bt_bmc->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
> - if (IS_ERR(bt_bmc->map)) {
> - void __iomem *base;
> -
> - /*
> - * Assume it's not the MFD-based devicetree description, in
> - * which case generate a regmap ourselves
> - */
> - base = devm_platform_ioremap_resource(pdev, 0);
> - if (IS_ERR(base))
> - return PTR_ERR(base);
> -
> - bt_bmc->map = devm_regmap_init_mmio(dev, base,
> &bt_regmap_cfg);
> - bt_bmc->offset = 0;
> - } else {
> - rc = of_property_read_u32(dev->of_node, "reg",
> &bt_bmc->offset);
> - if (rc)
> - return rc;
> - }
> + bt_bmc->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(bt_bmc->base))
> + return PTR_ERR(bt_bmc->base);
>
> mutex_init(&bt_bmc->mutex);
> init_waitqueue_head(&bt_bmc->queue);
> @@ -483,12 +447,12 @@ static int bt_bmc_probe(struct platform_device *pdev)
> add_timer(&bt_bmc->poll_timer);
> }
>
> - regmap_write(bt_bmc->map, bt_bmc->offset + BT_CR0,
> - (BT_IO_BASE << BT_CR0_IO_BASE) |
> + writel((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_CR0_ENABLE_IBT,
> + bt_bmc->base + BT_CR0);
>
> clr_b_busy(bt_bmc);
>
> --
> 2.33.0
>
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