Re: [PATCH v11 3/9] ARM: l2c: Refactor the driver to use commit-like interface

Nishanth Menon
2015-01-05T17:23:30Z

On 13:19-20150105, Marek Szyprowski wrote:
> From: Tomasz Figa <t.figa@samsung.com>
>
> Certain implementations of secure hypervisors (namely the one found on
> Samsung Exynos-based boards) do not provide access to individual L2C
> registers. This makes the .write_sec()-based interface insufficient and
> provoking ugly hacks.
>
> This patch is first step to make the driver not rely on availability of
> writes to individual registers. This is achieved by refactoring the
> driver to use a commit-like operation scheme: all register values are
> prepared first and stored in an instance of l2x0_regs struct and then a
> single callback is responsible to flush those values to the hardware.
>
> Signed-off-by: Tomasz Figa <t.figa@samsung.com>
> [mszyprow: rebased onto 'ARM: l2c: use l2c_write_sec() for restoring
> latency and filter regs' patch]
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
> arch/arm/mm/cache-l2x0.c | 210 ++++++++++++++++++++++++++---------------------
> 1 file changed, 115 insertions(+), 95 deletions(-)
>
> diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
> index 0aeeaa95c42d..f9013320c8ce 100644
> --- a/arch/arm/mm/cache-l2x0.c
> +++ b/arch/arm/mm/cache-l2x0.c
> @@ -41,12 +41,14 @@ struct l2c_init_data {
> void (*enable)(void __iomem *, u32, unsigned);
> void (*fixup)(void __iomem *, u32, struct outer_cache_fns *);
> void (*save)(void __iomem *);
> + void (*configure)(void __iomem *);
> struct outer_cache_fns outer_cache;
> };
>
> #define CACHE_LINE_SIZE 32
>
> static void __iomem *l2x0_base;
> +static const struct l2c_init_data *l2x0_data;
> static DEFINE_RAW_SPINLOCK(l2x0_lock);
> static u32 l2x0_way_mask; /* Bitmask of active ways */
> static u32 l2x0_size;
> @@ -106,6 +108,14 @@ static inline void l2c_unlock(void __iomem *base, unsigned num)
> }
> }
>
> +static void l2c_configure(void __iomem *base)
> +{
> + if (l2x0_data->configure)
> + l2x0_data->configure(base);
> +
> + l2c_write_sec(l2x0_saved_regs.aux_ctrl, base, L2X0_AUX_CTRL);
> +}
> +
> /*
> * Enable the L2 cache controller. This function must only be
> * called when the cache controller is known to be disabled.
> @@ -114,7 +124,12 @@ static void l2c_enable(void __iomem *base, u32 aux, unsigned num_lock)
> {
> unsigned long flags;
>
> - l2c_write_sec(aux, base, L2X0_AUX_CTRL);
> + /* Do not touch the controller if already enabled. */
> + if (readl_relaxed(base + L2X0_CTRL) & L2X0_CTRL_EN)
> + return;
> +
> + l2x0_saved_regs.aux_ctrl = aux;
> + l2c_configure(base);
>
> l2c_unlock(base, num_lock);
>
> @@ -208,6 +223,11 @@ static void l2c_save(void __iomem *base)
> l2x0_saved_regs.aux_ctrl = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
> }
>
> +static void l2c_resume(void)
> +{
> + l2c_enable(l2x0_base, l2x0_saved_regs.aux_ctrl, l2x0_data->num_lock);
> +}
> +
> /*
> * L2C-210 specific code.
> *
> @@ -288,14 +308,6 @@ static void l2c210_sync(void)
> __l2c210_cache_sync(l2x0_base);
> }
>
> -static void l2c210_resume(void)
> -{
> - void __iomem *base = l2x0_base;
> -
> - if (!(readl_relaxed(base + L2X0_CTRL) & L2X0_CTRL_EN))
> - l2c_enable(base, l2x0_saved_regs.aux_ctrl, 1);
> -}
> -
> static const struct l2c_init_data l2c210_data __initconst = {
> .type = "L2C-210",
> .way_size_0 = SZ_8K,
> @@ -309,7 +321,7 @@ static const struct l2c_init_data l2c210_data __initconst = {
> .flush_all = l2c210_flush_all,
> .disable = l2c_disable,
> .sync = l2c210_sync,
> - .resume = l2c210_resume,
> + .resume = l2c_resume,
> },
> };
>
> @@ -466,7 +478,7 @@ static const struct l2c_init_data l2c220_data = {
> .flush_all = l2c220_flush_all,
> .disable = l2c_disable,
> .sync = l2c220_sync,
> - .resume = l2c210_resume,
> + .resume = l2c_resume,
> },
> };
>
> @@ -615,39 +627,29 @@ static void __init l2c310_save(void __iomem *base)
> L310_POWER_CTRL);
> }
>
> -static void l2c310_resume(void)
> +static void l2c310_configure(void __iomem *base)
> {
> - void __iomem *base = l2x0_base;
> + unsigned revision;
>
> - if (!(readl_relaxed(base + L2X0_CTRL) & L2X0_CTRL_EN)) {
> - unsigned revision;
> -
> - /* restore pl310 setup */
> - l2c_write_sec(l2x0_saved_regs.tag_latency, base,
> - L310_TAG_LATENCY_CTRL);
> - l2c_write_sec(l2x0_saved_regs.data_latency, base,
> - L310_DATA_LATENCY_CTRL);
> - l2c_write_sec(l2x0_saved_regs.filter_end, base,
> - L310_ADDR_FILTER_END);
> - l2c_write_sec(l2x0_saved_regs.filter_start, base,
> - L310_ADDR_FILTER_START);
> -
> - revision = readl_relaxed(base + L2X0_CACHE_ID) &
> - L2X0_CACHE_ID_RTL_MASK;
> -
> - if (revision >= L310_CACHE_ID_RTL_R2P0)
> - l2c_write_sec(l2x0_saved_regs.prefetch_ctrl, base,
> - L310_PREFETCH_CTRL);
> - if (revision >= L310_CACHE_ID_RTL_R3P0)
> - l2c_write_sec(l2x0_saved_regs.pwr_ctrl, base,
> - L310_POWER_CTRL);
> -
> - l2c_enable(base, l2x0_saved_regs.aux_ctrl, 8);
> -
> - /* Re-enable full-line-of-zeros for Cortex-A9 */
> - if (l2x0_saved_regs.aux_ctrl & L310_AUX_CTRL_FULL_LINE_ZERO)
> - set_auxcr(get_auxcr() | BIT(3) | BIT(2) | BIT(1));
> - }
> + /* restore pl310 setup */
> + l2c_write_sec(l2x0_saved_regs.tag_latency, base,
> + L310_TAG_LATENCY_CTRL);
> + l2c_write_sec(l2x0_saved_regs.data_latency, base,
> + L310_DATA_LATENCY_CTRL);
> + l2c_write_sec(l2x0_saved_regs.filter_end, base,
> + L310_ADDR_FILTER_END);
> + l2c_write_sec(l2x0_saved_regs.filter_start, base,
> + L310_ADDR_FILTER_START);
> +
> + revision = readl_relaxed(base + L2X0_CACHE_ID) &
> + L2X0_CACHE_ID_RTL_MASK;
> +
> + if (revision >= L310_CACHE_ID_RTL_R2P0)
> + l2c_write_sec(l2x0_saved_regs.prefetch_ctrl, base,
> + L310_PREFETCH_CTRL);
> + if (revision >= L310_CACHE_ID_RTL_R3P0)
> + l2c_write_sec(l2x0_saved_regs.pwr_ctrl, base,
> + L310_POWER_CTRL);
> }
>
> static int l2c310_cpu_enable_flz(struct notifier_block *nb, unsigned long act, void *data)
> @@ -699,6 +701,23 @@ static void __init l2c310_enable(void __iomem *base, u32 aux, unsigned num_lock)
> aux &= ~(L310_AUX_CTRL_FULL_LINE_ZERO | L310_AUX_CTRL_EARLY_BRESP);
> }
>
> + /* r3p0 or later has power control register */
> + if (rev >= L310_CACHE_ID_RTL_R3P0)
> + l2x0_saved_regs.pwr_ctrl = L310_DYNAMIC_CLK_GATING_EN |
> + L310_STNDBY_MODE_EN;
> +
> + /*
> + * Always enable non-secure access to the lockdown registers -
> + * we write to them as part of the L2C enable sequence so they
> + * need to be accessible.
> + */
> + aux |= L310_AUX_CTRL_NS_LOCKDOWN;
> +
> + l2c_enable(base, aux, num_lock);
> +
> + /* Read back resulting AUX_CTRL value as it could have been altered. */
> + aux = readl_relaxed(base + L2X0_AUX_CTRL);
> +
> if (aux & (L310_AUX_CTRL_DATA_PREFETCH | L310_AUX_CTRL_INSTR_PREFETCH)) {
> u32 prefetch = readl_relaxed(base + L310_PREFETCH_CTRL);
>
> @@ -712,23 +731,12 @@ static void __init l2c310_enable(void __iomem *base, u32 aux, unsigned num_lock)
> if (rev >= L310_CACHE_ID_RTL_R3P0) {
> u32 power_ctrl;
>
> - l2c_write_sec(L310_DYNAMIC_CLK_GATING_EN | L310_STNDBY_MODE_EN,
> - base, L310_POWER_CTRL);
> power_ctrl = readl_relaxed(base + L310_POWER_CTRL);
> pr_info("L2C-310 dynamic clock gating %sabled, standby mode %sabled\n",
> power_ctrl & L310_DYNAMIC_CLK_GATING_EN ? "en" : "dis",
> power_ctrl & L310_STNDBY_MODE_EN ? "en" : "dis");
> }
>
> - /*
> - * Always enable non-secure access to the lockdown registers -
> - * we write to them as part of the L2C enable sequence so they
> - * need to be accessible.
> - */
> - aux |= L310_AUX_CTRL_NS_LOCKDOWN;
> -
> - l2c_enable(base, aux, num_lock);
> -
> if (aux & L310_AUX_CTRL_FULL_LINE_ZERO) {
> set_auxcr(get_auxcr() | BIT(3) | BIT(2) | BIT(1));
> cpu_notifier(l2c310_cpu_enable_flz, 0);
> @@ -760,11 +768,11 @@ static void __init l2c310_fixup(void __iomem *base, u32 cache_id,
>
> if (revision >= L310_CACHE_ID_RTL_R3P0 &&
> revision < L310_CACHE_ID_RTL_R3P2) {
> - u32 val = readl_relaxed(base + L310_PREFETCH_CTRL);
> + u32 val = l2x0_saved_regs.prefetch_ctrl;
> /* I don't think bit23 is required here... but iMX6 does so */
> if (val & (BIT(30) | BIT(23))) {
> val &= ~(BIT(30) | BIT(23));
> - l2c_write_sec(val, base, L310_PREFETCH_CTRL);
> + l2x0_saved_regs.prefetch_ctrl = val;
> errata[n++] = "752271";
> }
> }
> @@ -800,6 +808,15 @@ static void l2c310_disable(void)
> l2c_disable();
> }
>
> +static void l2c310_resume(void)
> +{
> + l2c_resume();
> +
> + /* Re-enable full-line-of-zeros for Cortex-A9 */
> + if (l2x0_saved_regs.aux_ctrl & L310_AUX_CTRL_FULL_LINE_ZERO)
> + set_auxcr(get_auxcr() | BIT(3) | BIT(2) | BIT(1));
> +}
> +
> static const struct l2c_init_data l2c310_init_fns __initconst = {
> .type = "L2C-310",
> .way_size_0 = SZ_8K,
> @@ -807,6 +824,7 @@ static const struct l2c_init_data l2c310_init_fns __initconst = {
> .enable = l2c310_enable,
> .fixup = l2c310_fixup,
> .save = l2c310_save,
> + .configure = l2c310_configure,
> .outer_cache = {
> .inv_range = l2c210_inv_range,
> .clean_range = l2c210_clean_range,
> @@ -818,7 +836,7 @@ static const struct l2c_init_data l2c310_init_fns __initconst = {
> },
> };
>
> -static void __init __l2c_init(const struct l2c_init_data *data,
> +static int __init __l2c_init(const struct l2c_init_data *data,
> u32 aux_val, u32 aux_mask, u32 cache_id)
> {
> struct outer_cache_fns fns;
> @@ -826,6 +844,14 @@ static void __init __l2c_init(const struct l2c_init_data *data,
> u32 aux, old_aux;
>
> /*
> + * Save the pointer globally so that callbacks which do not receive
> + * context from callers can access the structure.
> + */
> + l2x0_data = kmemdup(data, sizeof(*data), GFP_KERNEL);
> + if (!l2x0_data)
> + return -ENOMEM;
> +
> + /*
> * Sanity check the aux values. aux_mask is the bits we preserve
> * from reading the hardware register, and aux_val is the bits we
> * set.
> @@ -910,6 +936,8 @@ static void __init __l2c_init(const struct l2c_init_data *data,
> data->type, ways, l2x0_size >> 10);
> pr_info("%s: CACHE_ID 0x%08x, AUX_CTRL 0x%08x\n",
> data->type, cache_id, aux);
> +
> + return 0;
> }
>
> void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
> @@ -936,6 +964,10 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
> break;
> }
>
> + /* Read back current (default) hardware configuration */
> + if (data->save)
> + data->save(l2x0_base);
> +
> __l2c_init(data, aux_val, aux_mask, cache_id);
> }
>
> @@ -1102,7 +1134,7 @@ static const struct l2c_init_data of_l2c210_data __initconst = {
> .flush_all = l2c210_flush_all,
> .disable = l2c_disable,
> .sync = l2c210_sync,
> - .resume = l2c210_resume,
> + .resume = l2c_resume,
> },
> };
>
> @@ -1120,7 +1152,7 @@ static const struct l2c_init_data of_l2c220_data __initconst = {
> .flush_all = l2c220_flush_all,
> .disable = l2c_disable,
> .sync = l2c220_sync,
> - .resume = l2c210_resume,
> + .resume = l2c_resume,
> },
> };
>
> @@ -1135,28 +1167,26 @@ static void __init l2c310_of_parse(const struct device_node *np,
>
> of_property_read_u32_array(np, "arm,tag-latency", tag, ARRAY_SIZE(tag));
> if (tag[0] && tag[1] && tag[2])
> - writel_relaxed(
> + l2x0_saved_regs.tag_latency =
> L310_LATENCY_CTRL_RD(tag[0] - 1) |
> L310_LATENCY_CTRL_WR(tag[1] - 1) |
> - L310_LATENCY_CTRL_SETUP(tag[2] - 1),
> - l2x0_base + L310_TAG_LATENCY_CTRL);
> + L310_LATENCY_CTRL_SETUP(tag[2] - 1);
>
> of_property_read_u32_array(np, "arm,data-latency",
> data, ARRAY_SIZE(data));
> if (data[0] && data[1] && data[2])
> - writel_relaxed(
> + l2x0_saved_regs.data_latency =
> L310_LATENCY_CTRL_RD(data[0] - 1) |
> L310_LATENCY_CTRL_WR(data[1] - 1) |
> - L310_LATENCY_CTRL_SETUP(data[2] - 1),
> - l2x0_base + L310_DATA_LATENCY_CTRL);
> + L310_LATENCY_CTRL_SETUP(data[2] - 1);
>
> of_property_read_u32_array(np, "arm,filter-ranges",
> filter, ARRAY_SIZE(filter));
> if (filter[1]) {
> - writel_relaxed(ALIGN(filter[0] + filter[1], SZ_1M),
> - l2x0_base + L310_ADDR_FILTER_END);
> - writel_relaxed((filter[0] & ~(SZ_1M - 1)) | L310_ADDR_FILTER_EN,
> - l2x0_base + L310_ADDR_FILTER_START);
> + l2x0_saved_regs.filter_end =
> + ALIGN(filter[0] + filter[1], SZ_1M);
> + l2x0_saved_regs.filter_start = (filter[0] & ~(SZ_1M - 1))
> + | L310_ADDR_FILTER_EN;
> }
>
> ret = l2x0_cache_size_of_parse(np, aux_val, aux_mask, &assoc, SZ_512K);
> @@ -1188,6 +1218,7 @@ static const struct l2c_init_data of_l2c310_data __initconst = {
> .enable = l2c310_enable,
> .fixup = l2c310_fixup,
> .save = l2c310_save,
> + .configure = l2c310_configure,
> .outer_cache = {
> .inv_range = l2c210_inv_range,
> .clean_range = l2c210_clean_range,
> @@ -1216,6 +1247,7 @@ static const struct l2c_init_data of_l2c310_coherent_data __initconst = {
> .enable = l2c310_enable,
> .fixup = l2c310_fixup,
> .save = l2c310_save,
> + .configure = l2c310_configure,
> .outer_cache = {
> .inv_range = l2c210_inv_range,
> .clean_range = l2c210_clean_range,
> @@ -1330,16 +1362,6 @@ static void aurora_save(void __iomem *base)
> l2x0_saved_regs.aux_ctrl = readl_relaxed(base + L2X0_AUX_CTRL);
> }
>
> -static void aurora_resume(void)
> -{
> - void __iomem *base = l2x0_base;
> -
> - if (!(readl(base + L2X0_CTRL) & L2X0_CTRL_EN)) {
> - writel_relaxed(l2x0_saved_regs.aux_ctrl, base + L2X0_AUX_CTRL);
> - writel_relaxed(l2x0_saved_regs.ctrl, base + L2X0_CTRL);
> - }
> -}
> -
> /*
> * For Aurora cache in no outer mode, enable via the CP15 coprocessor
> * broadcasting of cache commands to L2.
> @@ -1401,7 +1423,7 @@ static const struct l2c_init_data of_aurora_with_outer_data __initconst = {
> .flush_all = l2x0_flush_all,
> .disable = l2x0_disable,
> .sync = l2x0_cache_sync,
> - .resume = aurora_resume,
> + .resume = l2c_resume,
> },
> };
>
> @@ -1414,7 +1436,7 @@ static const struct l2c_init_data of_aurora_no_outer_data __initconst = {
> .fixup = aurora_fixup,
> .save = aurora_save,
> .outer_cache = {
> - .resume = aurora_resume,
> + .resume = l2c_resume,
> },
> };
>
> @@ -1562,6 +1584,7 @@ static const struct l2c_init_data of_bcm_l2x0_data __initconst = {
> .of_parse = l2c310_of_parse,
> .enable = l2c310_enable,
> .save = l2c310_save,
> + .configure = l2c310_configure,
> .outer_cache = {
> .inv_range = bcm_inv_range,
> .clean_range = bcm_clean_range,
> @@ -1583,18 +1606,12 @@ static void __init tauros3_save(void __iomem *base)
> readl_relaxed(base + L310_PREFETCH_CTRL);
> }
>
> -static void tauros3_resume(void)
> +static void tauros3_configure(void __iomem *base)
> {
> - void __iomem *base = l2x0_base;
> -
> - if (!(readl_relaxed(base + L2X0_CTRL) & L2X0_CTRL_EN)) {
> - writel_relaxed(l2x0_saved_regs.aux2_ctrl,
> - base + TAUROS3_AUX2_CTRL);
> - writel_relaxed(l2x0_saved_regs.prefetch_ctrl,
> - base + L310_PREFETCH_CTRL);
> -
> - l2c_enable(base, l2x0_saved_regs.aux_ctrl, 8);
> - }
> + writel_relaxed(l2x0_saved_regs.aux2_ctrl,
> + base + TAUROS3_AUX2_CTRL);
> + writel_relaxed(l2x0_saved_regs.prefetch_ctrl,
> + base + L310_PREFETCH_CTRL);
> }
>
> static const struct l2c_init_data of_tauros3_data __initconst = {
> @@ -1603,9 +1620,10 @@ static const struct l2c_init_data of_tauros3_data __initconst = {
> .num_lock = 8,
> .enable = l2c_enable,
> .save = tauros3_save,
> + .configure = tauros3_configure,
> /* Tauros3 broadcasts L1 cache operations to L2 */
> .outer_cache = {
> - .resume = tauros3_resume,
> + .resume = l2c_resume,
> },
> };
>
> @@ -1661,6 +1679,10 @@ int __init l2x0_of_init(u32 aux_val, u32 aux_mask)
> if (!of_property_read_bool(np, "cache-unified"))
> pr_err("L2C: device tree omits to specify unified cache\n");
>
> + /* Read back current (default) hardware configuration */
> + if (data->save)
> + data->save(l2x0_base);
> +
> /* L2 configuration can only be changed if the cache is disabled */
> if (!(readl_relaxed(l2x0_base + L2X0_CTRL) & L2X0_CTRL_EN))
> if (data->of_parse)
> @@ -1671,8 +1693,6 @@ int __init l2x0_of_init(u32 aux_val, u32 aux_mask)
> else
> cache_id = readl_relaxed(l2x0_base + L2X0_CACHE_ID);
>
> - __l2c_init(data, aux_val, aux_mask, cache_id);
> -
> - return 0;
> + return __l2c_init(data, aux_val, aux_mask, cache_id);
> }
> #endif
> --
> 1.9.2
>

Based on two painful debugs.. It would really be nice to have this patch
split up into tinier pieces.. I know I have no issues with this patch
anymore, but for others who might discover similar behavior, debug is a
little easier with a split up series.

--
Regards,
Nishanth Menon