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Date: Wed, 29 Jun 2016 17:17:09 +0100
From: Jon Hunter <jonathanh@...dia.com>
To: Stephen Warren <swarren@...dotorg.org>,
Thierry Reding <thierry.reding@...il.com>,
Alexandre Courbot <gnurou@...il.com>
CC: <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/6] soc/tegra: pmc: Fix early initialisation of PMC
On 28/06/16 11:38, Jon Hunter wrote:
> During early initialisation, the available power partitions for a given
> device is configured as well as the polarity of the PMC interrupt. Both
> of which should only be configured if there is a valid device node for
> the PMC device. This is because the soc data used for configuring the
> power partitions is only available if a device node for the PMC is found
> and the code to configure the interrupt polarity uses the device node
> pointer directly.
>
> Some early device-tree images may not have this device node and so fix
> this by ensuring the device node pointer is valid when configuring these
> items.
>
> Signed-off-by: Jon Hunter <jonathanh@...dia.com>
> ---
> drivers/soc/tegra/pmc.c | 34 ++++++++++++++++++----------------
> 1 file changed, 18 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
> index 52a9e9703668..2e031c4ad547 100644
> --- a/drivers/soc/tegra/pmc.c
> +++ b/drivers/soc/tegra/pmc.c
> @@ -1550,27 +1550,29 @@ static int __init tegra_pmc_early_init(void)
> return -ENXIO;
> }
>
> - /* Create a bit-map of the available and valid partitions */
> - for (i = 0; i < pmc->soc->num_powergates; i++)
> - if (pmc->soc->powergates[i])
> - set_bit(i, pmc->powergates_available);
> -
> mutex_init(&pmc->powergates_lock);
>
> - /*
> - * Invert the interrupt polarity if a PMC device tree node exists and
> - * contains the nvidia,invert-interrupt property.
> - */
> - invert = of_property_read_bool(np, "nvidia,invert-interrupt");
> + if (np) {
> + /* Create a bit-map of the available and valid partitions */
> + for (i = 0; i < pmc->soc->num_powergates; i++)
> + if (pmc->soc->powergates[i])
> + set_bit(i, pmc->powergates_available);
>
> - value = tegra_pmc_readl(PMC_CNTRL);
> + /*
> + * Invert the interrupt polarity if a PMC device tree node
> + * exists and contains the nvidia,invert-interrupt property.
> + */
> + invert = of_property_read_bool(np, "nvidia,invert-interrupt");
>
> - if (invert)
> - value |= PMC_CNTRL_INTR_POLARITY;
> - else
> - value &= ~PMC_CNTRL_INTR_POLARITY;
> + value = tegra_pmc_readl(PMC_CNTRL);
>
> - tegra_pmc_writel(value, PMC_CNTRL);
> + if (invert)
> + value |= PMC_CNTRL_INTR_POLARITY;
> + else
> + value &= ~PMC_CNTRL_INTR_POLARITY;
> +
> + tegra_pmc_writel(value, PMC_CNTRL);
> + }
>
> return 0;
> }
By the way, the more I think about this, if there is no valid 'pmc'
node in the device-tree blob, then I wonder if we should even bother
mapping the pmc address space at all? The reason being, if there is
no 'pmc' node then we cannot look-up the SoC data and so all the
public PMC APIs are pretty useless AFAICT. I wonder if we should do
something like ...
diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
index e09c7ed385f6..34d1385d7ef0 100644
--- a/drivers/soc/tegra/pmc.c
+++ b/drivers/soc/tegra/pmc.c
@@ -1510,7 +1510,6 @@ static int __init tegra_pmc_early_init(void)
{
const struct of_device_id *match;
struct device_node *np;
- struct resource regs;
unsigned int i;
bool invert;
u32 value;
@@ -1520,73 +1519,47 @@ static int __init tegra_pmc_early_init(void)
np = of_find_matching_node_and_match(NULL, tegra_pmc_match, &match);
if (!np) {
/*
- * Fall back to legacy initialization for 32-bit ARM only. All
- * 64-bit ARM device tree files for Tegra are required to have
- * a PMC node.
- *
- * This is for backwards-compatibility with old device trees
- * that didn't contain a PMC node. Note that in this case the
- * SoC data can't be matched and therefore powergating is
- * disabled.
+ * All 64-bit ARM device tree files for Tegra are required to
+ * have a PMC node. For old 32-bit Tegra device trees that
+ * don't contain a PMC node, the SoC data can't be matched
+ * and therefore powergating is disabled.
*/
- if (IS_ENABLED(CONFIG_ARM) && soc_is_tegra()) {
+ if (IS_ENABLED(CONFIG_ARM) && soc_is_tegra())
pr_warn("DT node not found, powergating disabled\n");
- regs.start = 0x7000e400;
- regs.end = 0x7000e7ff;
- regs.flags = IORESOURCE_MEM;
-
- pr_warn("Using memory region %pR\n", ®s);
- } else {
- /*
- * At this point we're not running on Tegra, so play
- * nice with multi-platform kernels.
- */
- return 0;
- }
- } else {
- /*
- * Extract information from the device tree if we've found a
- * matching node.
- */
- if (of_address_to_resource(np, 0, ®s) < 0) {
- pr_err("failed to get PMC registers\n");
- return -ENXIO;
- }
+ return 0;
}
- pmc->base = ioremap_nocache(regs.start, resource_size(®s));
+ pmc->base = of_iomap(np, 0);
if (!pmc->base) {
pr_err("failed to map PMC registers\n");
of_node_put(np);
return -ENXIO;
}
Cheers
Jon
--
nvpublic
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