Messages in this thread | | | From | Andy Shevchenko <> | Date | Wed, 16 May 2018 00:00:00 +0300 | Subject | Re: [patch v21 2/4] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver |
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On Tue, May 15, 2018 at 5:21 PM, Oleksandr Shamray <oleksandrs@mellanox.com> wrote: > Driver adds support of Aspeed 2500/2400 series SOC JTAG master controller. > > Driver implements the following jtag ops: > - freq_get; > - freq_set; > - status_get; > - idle; > - xfer; > > It has been tested on Mellanox system with BMC equipped with > Aspeed 2520 SoC for programming CPLD devices.
> +#define ASPEED_JTAG_DATA 0x00 > +#define ASPEED_JTAG_INST 0x04 > +#define ASPEED_JTAG_CTRL 0x08 > +#define ASPEED_JTAG_ISR 0x0C > +#define ASPEED_JTAG_SW 0x10 > +#define ASPEED_JTAG_TCK 0x14 > +#define ASPEED_JTAG_EC 0x18 > + > +#define ASPEED_JTAG_DATA_MSB 0x01 > +#define ASPEED_JTAG_DATA_CHUNK_SIZE 0x20
> +#define ASPEED_JTAG_IOUT_LEN(len) (ASPEED_JTAG_CTL_ENG_EN |\ > + ASPEED_JTAG_CTL_ENG_OUT_EN |\ > + ASPEED_JTAG_CTL_INST_LEN(len))
Better to read
#define MY_COOL_CONST_OR_MACRO(xxx) \ ...
> +#define ASPEED_JTAG_DOUT_LEN(len) (ASPEED_JTAG_CTL_ENG_EN |\ > + ASPEED_JTAG_CTL_ENG_OUT_EN |\ > + ASPEED_JTAG_CTL_DATA_LEN(len))
Ditto.
> +static char *end_status_str[] = {"idle", "ir pause", "drpause"};
> +static int aspeed_jtag_freq_set(struct jtag *jtag, u32 freq) > +{ > + struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag); > + unsigned long apb_frq; > + u32 tck_val; > + u16 div; > + > + apb_frq = clk_get_rate(aspeed_jtag->pclk);
> + div = (apb_frq % freq == 0) ? (apb_frq / freq) - 1 : (apb_frq / freq);
Isn't it the same as
div = (apb_frq - 1) / freq;
?
> + tck_val = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK); > + aspeed_jtag_write(aspeed_jtag, > + (tck_val & ASPEED_JTAG_TCK_DIVISOR_MASK) | div, > + ASPEED_JTAG_TCK); > + return 0; > +}
> +static void aspeed_jtag_sw_delay(struct aspeed_jtag *aspeed_jtag, int cnt) > +{ > + int i; > + > + for (i = 0; i < cnt; i++) > + aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW);
Isn't it readsl() (or how it's called, I don't remember).
> +}
> +static void aspeed_jtag_wait_instruction_pause(struct aspeed_jtag *aspeed_jtag) > +{ > + wait_event_interruptible(aspeed_jtag->jtag_wq, aspeed_jtag->flag & > + ASPEED_JTAG_ISR_INST_PAUSE);
In such cases I prefer to see a new line with a parameter in full. Check all places.
> + aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_PAUSE; > +}
> +static void aspeed_jtag_sm_cycle(struct aspeed_jtag *aspeed_jtag, const u8 *tms, > + int len) > +{ > + int i; > + > + for (i = 0; i < len; i++) > + aspeed_jtag_tck_cycle(aspeed_jtag, tms[i], 0); > +} > + > +static void aspeed_jtag_run_test_idle_sw(struct aspeed_jtag *aspeed_jtag, > + struct jtag_run_test_idle *runtest) > +{ > + static const u8 sm_pause_irpause[] = {1, 1, 1, 1, 0, 1, 0}; > + static const u8 sm_pause_drpause[] = {1, 1, 1, 0, 1, 0}; > + static const u8 sm_idle_irpause[] = {1, 1, 0, 1, 0}; > + static const u8 sm_idle_drpause[] = {1, 0, 1, 0}; > + static const u8 sm_pause_idle[] = {1, 1, 0}; > + int i; > + > + /* SW mode from idle/pause-> to pause/idle */ > + if (runtest->reset) { > + for (i = 0; i < ASPEED_JTAG_RESET_CNTR; i++) > + aspeed_jtag_tck_cycle(aspeed_jtag, 1, 0); > + }
I would rather split this big switch to a few helper functions per each status of surrounding switch.
> + > + /* Stay on IDLE for at least TCK cycle */ > + for (i = 0; i < runtest->tck; i++) > + aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0); > +}
> +/** > + * aspeed_jtag_run_test_idle: > + * JTAG reset: generates at least 9 TMS high and 1 TMS low to force > + * devices into Run-Test/Idle State. > + */
It's rather broken kernel doc.
> + aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN | > + ASPEED_JTAG_CTL_ENG_OUT_EN | > + ASPEED_JTAG_CTL_FORCE_TMS, ASPEED_JTAG_CTRL);
> + aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_EC_GO_IDLE, > + ASPEED_JTAG_EC);
> + aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN | > + ASPEED_JTAG_SW_MODE_TDIO, ASPEED_JTAG_SW);
Here you have permutations of flag some of which are repeatetive in the code. Perhaps make additional definitions instead. Check other similar places.
> + char tdo;
Indentation.
> + if (xfer->direction == JTAG_READ_XFER) > + tdi = UINT_MAX; > + else > + tdi = data[index];
> + if (xfer->direction == JTAG_READ_XFER) > + tdi = UINT_MAX; > + else > + tdi = data[index];
Take your time to think how the above duplication can be avoided.
> + } > + } > + > + tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 1, tdi & ASPEED_JTAG_DATA_MSB); > + data[index] |= tdo << (shift_bits % ASPEED_JTAG_DATA_CHUNK_SIZE); > +}
> + if (endstate != JTAG_STATE_IDLE) {
Why not to use positive check?
> + int i; > + > + for (i = 0; i <= xfer->length / BITS_PER_BYTE; i++) { > + pos += snprintf(&dbg_str[pos], sizeof(dbg_str) - pos, > + "0x%02x ", xfer_data[i]); > + }
Oh, NO! Consider reading printk-formats (for %*ph) and other documentation about available APIs.
> + if (!(aspeed_jtag->mode & JTAG_XFER_HW_MODE)) { > + /* SW mode */
This is rather too complex to be in one function.
> + } else {
> + /* hw mode */ > + aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW); > + aspeed_jtag_xfer_hw(aspeed_jtag, xfer, data);
For symmetry it might be another function.
> + }
> + dev_dbg(aspeed_jtag->dev, "status %x\n", status);
Perhaps someone should become familiar with tracepoints?
> + dev_err(aspeed_jtag->dev, "irq status:%x\n", > + status);
Huh, really?! SPAM.
(I would drop it completely, though you may use ratelimited variant)
> + ret = IRQ_NONE; > + } > + return ret; > +}
> + clk_prepare_enable(aspeed_jtag->pclk);
This might fail.
> + dev_dbg(&pdev->dev, "IRQ %d.\n", aspeed_jtag->irq);
Noise even for debug.
> + err = jtag_register(jtag);
Perhaps we might have devm_ variant of this. Check how SPI framework deal with a such.
> +static int aspeed_jtag_remove(struct platform_device *pdev) > +{
> + struct jtag *jtag; > + > + jtag = platform_get_drvdata(pdev);
Usually we put this on one line
> + aspeed_jtag_deinit(pdev, jtag_priv(jtag)); > + jtag_unregister(jtag); > + jtag_free(jtag); > + return 0; > +}
-- With Best Regards, Andy Shevchenko
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